diff --git a/aio/aio-builds-setup/dockerbuild/scripts-js/lib/common/circle-ci-api.ts b/aio/aio-builds-setup/dockerbuild/scripts-js/lib/common/circle-ci-api.ts
index c416ca48414..592ddd7407c 100644
--- a/aio/aio-builds-setup/dockerbuild/scripts-js/lib/common/circle-ci-api.ts
+++ b/aio/aio-builds-setup/dockerbuild/scripts-js/lib/common/circle-ci-api.ts
@@ -1,5 +1,6 @@
 // Imports
 import fetch from 'node-fetch';
+
 import {assertNotMissingOrEmpty} from './utils';
 
 // Constants
@@ -22,8 +23,8 @@ export interface BuildInfo {
   username: string;
   build_num: number;
   has_artifacts: boolean;
-  outcome: string; // e.g. 'success'
-  vcs_revision: string; // HEAD SHA
+  outcome: string;       // e.g. 'success'
+  vcs_revision: string;  // HEAD SHA
   // there are other fields but they are not used in this code
 }
 
@@ -31,19 +32,19 @@ export interface BuildInfo {
  * A Helper that can interact with the CircleCI API.
  */
 export class CircleCiApi {
-
   private tokenParam = `circle-token=${this.circleCiToken}`;
 
   /**
    * Construct a helper that can interact with the CircleCI REST API.
-   * @param githubOrg The Github organisation whose repos we want to access in CircleCI (e.g. angular).
+   * @param githubOrg The Github organisation whose repos we want to access in CircleCI (e.g.
+   *     angular).
    * @param githubRepo The Github repo whose builds we want to access in CircleCI (e.g. angular).
    * @param circleCiToken The CircleCI API access token (secret).
    */
   constructor(
-    private githubOrg: string,
-    private githubRepo: string,
-    private circleCiToken: string,
+      private githubOrg: string,
+      private githubRepo: string,
+      private circleCiToken: string,
   ) {
     assertNotMissingOrEmpty('githubOrg', githubOrg);
     assertNotMissingOrEmpty('githubRepo', githubRepo);
@@ -64,7 +65,7 @@ export class CircleCiApi {
       }
       return response.json();
     } catch (error) {
-        throw new Error(`CircleCI build info request failed (${error.message})`);
+      throw new Error(`CircleCI build info request failed (${(error as Error).message})`);
     }
   }
 
@@ -84,7 +85,7 @@ export class CircleCiApi {
       }
       return artifact.url;
     } catch (error) {
-      throw new Error(`CircleCI artifact URL request failed (${error.message})`);
+      throw new Error(`CircleCI artifact URL request failed (${(error as Error).message})`);
     }
   }
 }
diff --git a/aio/aio-builds-setup/dockerbuild/scripts-js/lib/common/utils.ts b/aio/aio-builds-setup/dockerbuild/scripts-js/lib/common/utils.ts
index 870126ba955..ca1b7d83463 100644
--- a/aio/aio-builds-setup/dockerbuild/scripts-js/lib/common/utils.ts
+++ b/aio/aio-builds-setup/dockerbuild/scripts-js/lib/common/utils.ts
@@ -1,4 +1,5 @@
 import {basename, resolve as resolvePath} from 'path';
+
 import {SHORT_SHA_LEN} from './constants';
 
 /**
@@ -17,7 +18,8 @@ export function computeShortSha(sha: string) {
  * @param artifactPath The path to the artifact on CircleCI.
  * @returns The fully resolved location for the specified downloaded artifact.
  */
-export function computeArtifactDownloadPath(downloadsDir: string, pr: number, sha: string, artifactPath: string) {
+export function computeArtifactDownloadPath(
+    downloadsDir: string, pr: number, sha: string, artifactPath: string) {
   return resolvePath(downloadsDir, `${pr}-${computeShortSha(sha)}-${basename(artifactPath)}`);
 }
 
@@ -48,7 +50,7 @@ export function assert(value: boolean, message: string) {
  * @param name The name of the parameter.
  * @param value The value of the parameter.
  */
-export const assertNotMissingOrEmpty = (name: string, value: string | null | undefined) => {
+export const assertNotMissingOrEmpty = (name: string, value: string|null|undefined) => {
   assert(!!value, `Missing or empty required parameter '${name}'!`);
 };
 
@@ -64,9 +66,9 @@ export const getEnvVar = (name: string, isOptional = false): string => {
 
   if (!isOptional && !value) {
     try {
-     throw new Error(`ERROR: Missing required environment variable '${name}'!`);
+      throw new Error(`ERROR: Missing required environment variable '${name}'!`);
     } catch (error) {
-      console.error(error.stack);
+      console.error((error as Error).stack);
       process.exit(1);
     }
   }
@@ -76,7 +78,8 @@ export const getEnvVar = (name: string, isOptional = false): string => {
 
 /**
  * A basic logger implementation.
- * Delegates to `console`, but prepends each message with the current date and specified scope (i.e caller).
+ * Delegates to `console`, but prepends each message with the current date and specified scope (i.e
+ * caller).
  */
 export class Logger {
   private padding = ' '.repeat(20 - this.scope.length);
@@ -87,12 +90,20 @@ export class Logger {
    */
   constructor(private scope: string) {}
 
-  public error(...args: any[]) { this.callMethod('error', args); }
-  public info(...args: any[]) { this.callMethod('info', args); }
-  public log(...args: any[]) { this.callMethod('log', args); }
-  public warn(...args: any[]) { this.callMethod('warn', args); }
+  public error(...args: any[]) {
+    this.callMethod('error', args);
+  }
+  public info(...args: any[]) {
+    this.callMethod('info', args);
+  }
+  public log(...args: any[]) {
+    this.callMethod('log', args);
+  }
+  public warn(...args: any[]) {
+    this.callMethod('warn', args);
+  }
 
-  private callMethod(method: 'error' | 'info' | 'log' | 'warn', args: any[]) {
+  private callMethod(method: 'error'|'info'|'log'|'warn', args: any[]) {
     console[method](`[${new Date()}]`, `${this.scope}:${this.padding}`, ...args);
   }
 }
diff --git a/aio/aio-builds-setup/dockerbuild/scripts-js/lib/preview-server/build-retriever.ts b/aio/aio-builds-setup/dockerbuild/scripts-js/lib/preview-server/build-retriever.ts
index 2c29d6cd961..b06a770a12d 100644
--- a/aio/aio-builds-setup/dockerbuild/scripts-js/lib/preview-server/build-retriever.ts
+++ b/aio/aio-builds-setup/dockerbuild/scripts-js/lib/preview-server/build-retriever.ts
@@ -3,8 +3,10 @@ import fetch from 'node-fetch';
 import {dirname} from 'path';
 import {mkdir} from 'shelljs';
 import {promisify} from 'util';
+
 import {CircleCiApi} from '../common/circle-ci-api';
 import {assert, assertNotMissingOrEmpty, computeArtifactDownloadPath, Logger} from '../common/utils';
+
 import {PreviewServerError} from './preview-error';
 
 export interface GithubInfo {
@@ -20,8 +22,11 @@ export interface GithubInfo {
  */
 export class BuildRetriever {
   private logger = new Logger('BuildRetriever');
-  constructor(private api: CircleCiApi, private downloadSizeLimit: number, private downloadDir: string) {
-    assert(downloadSizeLimit > 0, 'Invalid parameter "downloadSizeLimit" should be a number greater than 0.');
+  constructor(
+      private api: CircleCiApi, private downloadSizeLimit: number, private downloadDir: string) {
+    assert(
+        downloadSizeLimit > 0,
+        'Invalid parameter "downloadSizeLimit" should be a number greater than 0.');
     assertNotMissingOrEmpty('downloadDir', downloadDir);
   }
 
@@ -50,25 +55,29 @@ export class BuildRetriever {
    * @param artifactPath the path on CircleCI where the artifact was stored.
    * @returns A promise to the file path where the downloaded file was stored.
    */
-  public async downloadBuildArtifact(buildNum: number, pr: number, sha: string, artifactPath: string): Promise<string> {
+  public async downloadBuildArtifact(
+      buildNum: number, pr: number, sha: string, artifactPath: string): Promise<string> {
     try {
       const outPath = computeArtifactDownloadPath(this.downloadDir, pr, sha, artifactPath);
-      const downloadExists = await new Promise(resolve => fs.exists(outPath, exists => resolve(exists)));
+      const downloadExists =
+          await new Promise(resolve => fs.exists(outPath, exists => resolve(exists)));
       if (!downloadExists) {
         const url = await this.api.getBuildArtifactUrl(buildNum, artifactPath);
         const response = await fetch(url, {size: this.downloadSizeLimit});
         if (response.status !== 200) {
-          throw new PreviewServerError(response.status, `Error ${response.status} - ${response.statusText}`);
+          throw new PreviewServerError(
+              response.status, `Error ${response.status} - ${response.statusText}`);
         }
         const buffer = await response.buffer();
         mkdir('-p', dirname(outPath));
         await promisify(fs.writeFile)(outPath, buffer);
       }
       return outPath;
-    } catch (error) {
+    } catch (error: any) {
       this.logger.warn(error);
       const status = (error.type === 'max-size') ? 413 : 500;
-      throw new PreviewServerError(status, `CircleCI artifact download failed (${error.message || error})`);
+      throw new PreviewServerError(
+          status, `CircleCI artifact download failed (${error.message || error})`);
     }
   }
 }
diff --git a/aio/aio-builds-setup/dockerbuild/scripts-js/test/preview-server/utils.spec.ts b/aio/aio-builds-setup/dockerbuild/scripts-js/test/preview-server/utils.spec.ts
index 993225711cd..5f0f36beaa2 100644
--- a/aio/aio-builds-setup/dockerbuild/scripts-js/test/preview-server/utils.spec.ts
+++ b/aio/aio-builds-setup/dockerbuild/scripts-js/test/preview-server/utils.spec.ts
@@ -1,4 +1,5 @@
 import * as express from 'express';
+
 import {PreviewServerError} from '../../lib/preview-server/preview-error';
 import {respondWithError, throwRequestError} from '../../lib/preview-server/utils';
 
@@ -37,11 +38,12 @@ describe('preview-server/utils', () => {
           originalUrl: 'some.domain.com/path',
         } as express.Request;
         throwRequestError(505, 'ERROR MESSAGE', request);
-      } catch (error) {
+      } catch (error: any) {
         caught = true;
         expect(error).toBeInstanceOf(PreviewServerError);
         expect(error.status).toEqual(505);
-        expect(error.message).toEqual(`ERROR MESSAGE in request: POST some.domain.com/path "The request body"`);
+        expect(error.message)
+            .toEqual(`ERROR MESSAGE in request: POST some.domain.com/path "The request body"`);
       }
       expect(caught).toEqual(true);
     });
diff --git a/aio/aio-builds-setup/dockerbuild/scripts-js/tsconfig.json b/aio/aio-builds-setup/dockerbuild/scripts-js/tsconfig.json
index 280fe4159c7..27847c75ae6 100644
--- a/aio/aio-builds-setup/dockerbuild/scripts-js/tsconfig.json
+++ b/aio/aio-builds-setup/dockerbuild/scripts-js/tsconfig.json
@@ -1,40 +1,36 @@
 {
   "compilerOptions": {
     /* Basic Options */
-    "target": "es5",                             /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', or 'ESNEXT'. */
-    "module": "commonjs",                        /* Specify module code generation: 'none', commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */
+    "target": "es5", /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', or 'ESNEXT'. */
+    "module": "commonjs", /* Specify module code generation: 'none', commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */
     "lib": [
       "es2015",
       "es2016.array.include"
-    ],                                        /* Specify library files to be included in the compilation:  */
+    ], /* Specify library files to be included in the compilation:  */
     // "allowJs": true,                          /* Allow javascript files to be compiled. */
     // "checkJs": true,                          /* Report errors in .js files. */
     // "jsx": "preserve",                        /* Specify JSX code generation: 'preserve', 'react-native', or 'react'. */
     // "declaration": true,                      /* Generates corresponding '.d.ts' file. */
     // "sourceMap": true,                        /* Generates corresponding '.map' file. */
     // "outFile": "./",                          /* Concatenate and emit output to single file. */
-    "outDir": "dist",                         /* Redirect output structure to the directory. */
+    "outDir": "dist", /* Redirect output structure to the directory. */
     // "rootDir": "./",                          /* Specify the root directory of input files. Use to control the output directory structure with --outDir. */
     // "removeComments": true,                   /* Do not emit comments to output. */
     // "noEmit": true,                           /* Do not emit outputs. */
-    "importHelpers": true,                    /* Import emit helpers from 'tslib'. */
+    "importHelpers": true, /* Import emit helpers from 'tslib'. */
     // "downlevelIteration": true,               /* Provide full support for iterables in 'for-of', spread, and destructuring when targeting 'ES5' or 'ES3'. */
     // "isolatedModules": true,                  /* Transpile each file as a separate module (similar to 'ts.transpileModule'). */
-
     /* Strict Type-Checking Options */
-    "strict": true,                              /* Enable all strict type-checking options. */
+    "strict": true, /* Enable all strict type-checking options. */
     // "noImplicitAny": true,                    /* Raise error on expressions and declarations with an implied 'any' type. */
     // "strictNullChecks": true,                 /* Enable strict null checks. */
     // "noImplicitThis": true,                   /* Raise error on 'this' expressions with an implied 'any' type. */
     // "alwaysStrict": true,                     /* Parse in strict mode and emit "use strict" for each source file. */
-
     /* Additional Checks */
-    "noUnusedLocals": true,                   /* Report errors on unused locals. */
-    "noUnusedParameters": true,               /* Report errors on unused parameters. */
-    "noImplicitReturns": true,                /* Report error when not all code paths in function return a value. */
+    "noUnusedLocals": true, /* Report errors on unused locals. */
+    "noUnusedParameters": true, /* Report errors on unused parameters. */
+    "noImplicitReturns": true, /* Report error when not all code paths in function return a value. */
     // "noFallthroughCasesInSwitch": true,       /* Report errors for fallthrough cases in switch statement. */
-    "useUnknownInCatchVariables": false,         /* Avoid having to cast error objects inside `catch` clauses. */
-
     /* Module Resolution Options */
     // "moduleResolution": "node",               /* Specify module resolution strategy: 'node' (Node.js) or 'classic' (TypeScript pre-1.6). */
     // "baseUrl": "./",                          /* Base directory to resolve non-absolute module names. */
@@ -42,29 +38,26 @@
     // "rootDirs": [],                           /* List of root folders whose combined content represents the structure of the project at runtime. */
     "typeRoots": [
       "node_modules/@types"
-    ],                                        /* List of folders to include type definitions from. */
+    ], /* List of folders to include type definitions from. */
     // "types": [],                              /* Type declaration files to be included in compilation. */
     // "allowSyntheticDefaultImports": true,     /* Allow default imports from modules with no default export. This does not affect code emit, just typechecking. */
     // "preserveSymlinks": true,                 /* Do not resolve the real path of symlinks. */
-
     /* Source Map Options */
     // "sourceRoot": "./",                       /* Specify the location where debugger should locate TypeScript files instead of source locations. */
     // "mapRoot": "./",                          /* Specify the location where debugger should locate map files instead of generated locations. */
-    "inlineSourceMap": true,                  /* Emit a single file with source maps instead of having a separate file. */
+    "inlineSourceMap": true, /* Emit a single file with source maps instead of having a separate file. */
     // "inlineSources": true,                    /* Emit the source alongside the sourcemaps within a single file; requires '--inlineSourceMap' or '--sourceMap' to be set. */
-
     /* Experimental Options */
     // "experimentalDecorators": true,           /* Enables experimental support for ES7 decorators. */
     // "emitDecoratorMetadata": true,            /* Enables experimental support for emitting type metadata for decorators. */
-
     /* Other */
     "forceConsistentCasingInFileNames": true, /* Disallow inconsistently-cased references to the same file. */
-    "newLine": "LF",                          /* Use the specified end of line sequence to be used when emitting files: "crlf" (windows) or "lf" (unix). */
-    "pretty": true,                           /* Stylize errors and messages using color and context. */
-    "skipLibCheck": true                      /* Skip type checking of all declaration files (*.d.ts). */
+    "newLine": "LF", /* Use the specified end of line sequence to be used when emitting files: "crlf" (windows) or "lf" (unix). */
+    "pretty": true, /* Stylize errors and messages using color and context. */
+    "skipLibCheck": true /* Skip type checking of all declaration files (*.d.ts). */
   },
   "include": [
     "lib/**/*",
     "test/**/*"
   ]
-}
+}
\ No newline at end of file
diff --git a/aio/src/app/layout/doc-viewer/doc-viewer.component.ts b/aio/src/app/layout/doc-viewer/doc-viewer.component.ts
index 2adff61ff75..4b42b0bd264 100644
--- a/aio/src/app/layout/doc-viewer/doc-viewer.component.ts
+++ b/aio/src/app/layout/doc-viewer/doc-viewer.component.ts
@@ -1,15 +1,13 @@
-import { Component, ElementRef, EventEmitter, Input, OnDestroy, Output } from '@angular/core';
-import { Title, Meta } from '@angular/platform-browser';
-
-import { asapScheduler, Observable, of, timer } from 'rxjs';
-import { catchError, observeOn, switchMap, takeUntil, tap } from 'rxjs/operators';
-import { EMPTY_HTML, unwrapHtmlForSink } from 'safevalues';
-
-import { DocumentContents, FILE_NOT_FOUND_ID, FETCHING_ERROR_ID } from 'app/documents/document.service';
-import { Logger } from 'app/shared/logger.service';
-import { TocService } from 'app/shared/toc.service';
-import { ElementsLoader } from 'app/custom-elements/elements-loader';
-import { fromInnerHTML } from 'app/shared/security';
+import {Component, ElementRef, EventEmitter, Input, OnDestroy, Output} from '@angular/core';
+import {Meta, Title} from '@angular/platform-browser';
+import {ElementsLoader} from 'app/custom-elements/elements-loader';
+import {DocumentContents, FETCHING_ERROR_ID, FILE_NOT_FOUND_ID} from 'app/documents/document.service';
+import {Logger} from 'app/shared/logger.service';
+import {fromInnerHTML} from 'app/shared/security';
+import {TocService} from 'app/shared/toc.service';
+import {asapScheduler, Observable, of, timer} from 'rxjs';
+import {catchError, observeOn, switchMap, takeUntil, tap} from 'rxjs/operators';
+import {EMPTY_HTML, unwrapHtmlForSink} from 'safevalues';
 
 
 // Constants
@@ -17,7 +15,8 @@ export const NO_ANIMATIONS = 'no-animations';
 
 // Initialization prevents flicker once pre-rendering is on
 const initialDocViewerElement = document.querySelector('aio-doc-viewer');
-const initialDocViewerContent = initialDocViewerElement ? fromInnerHTML(initialDocViewerElement) : EMPTY_HTML;
+const initialDocViewerContent =
+    initialDocViewerElement ? fromInnerHTML(initialDocViewerElement) : EMPTY_HTML;
 
 @Component({
   selector: 'aio-doc-viewer',
@@ -61,15 +60,13 @@ export class DocViewerComponent implements OnDestroy {
   @Output() docRendered = new EventEmitter<void>();
 
   constructor(
-    elementRef: ElementRef,
-    private logger: Logger,
-    private titleService: Title,
-    private metaService: Meta,
-    private tocService: TocService,
-    private elementsLoader: ElementsLoader) {
+      elementRef: ElementRef, private logger: Logger, private titleService: Title,
+      private metaService: Meta, private tocService: TocService,
+      private elementsLoader: ElementsLoader) {
     this.hostElement = elementRef.nativeElement;
 
-    // Security: the initialDocViewerContent comes from the prerendered DOM and is considered to be secure
+    // Security: the initialDocViewerContent comes from the prerendered DOM and is considered to be
+    // secure
     this.hostElement.innerHTML = unwrapHtmlForSink(initialDocViewerContent);
 
     if (this.hostElement.firstElementChild) {
@@ -81,7 +78,7 @@ export class DocViewerComponent implements OnDestroy {
             observeOn(asapScheduler),
             switchMap(newDoc => this.render(newDoc)),
             takeUntil(this.onDestroy$),
-        )
+            )
         .subscribe();
   }
 
@@ -151,7 +148,8 @@ export class DocViewerComponent implements OnDestroy {
         tap(() => this.docRendered.emit()),
         catchError(err => {
           const errorMessage = `${(err instanceof Error) ? err.stack : err}`;
-          this.logger.error(new Error(`[DocViewer] Error preparing document '${doc.id}': ${errorMessage}`));
+          this.logger.error(
+              new Error(`[DocViewer] Error preparing document '${doc.id}': ${errorMessage}`));
           this.nextViewContainer.textContent = '';
           this.setNoIndex(true);
 
@@ -172,7 +170,7 @@ export class DocViewerComponent implements OnDestroy {
    */
   private setNoIndex(val: boolean) {
     if (val) {
-      this.metaService.addTag({ name: 'robots', content: 'noindex' });
+      this.metaService.addTag({name: 'robots', content: 'noindex'});
     } else {
       this.metaService.removeTag('name="robots"');
     }
@@ -207,29 +205,33 @@ export class DocViewerComponent implements OnDestroy {
 
     // Some properties are not assignable and thus cannot be animated.
     // Example methods, readonly and CSS properties:
-    // "length", "parentRule", "getPropertyPriority", "getPropertyValue", "item", "removeProperty", "setProperty"
+    // "length", "parentRule", "getPropertyPriority", "getPropertyValue", "item", "removeProperty",
+    // "setProperty"
     type StringValueCSSStyleDeclaration = Exclude<
-      {
-        [K in keyof CSSStyleDeclaration]: CSSStyleDeclaration[K] extends string ? K : never;
-      }[keyof CSSStyleDeclaration],
-      number
-    >;
+        {[K in keyof CSSStyleDeclaration]:
+             CSSStyleDeclaration[K] extends string ? K : never;}[keyof CSSStyleDeclaration],
+        number>;
     const animateProp =
-        (elem: HTMLElement, prop: StringValueCSSStyleDeclaration, from: string, to: string, duration = 200) => {
+        (elem: HTMLElement, prop: StringValueCSSStyleDeclaration, from: string, to: string,
+         duration = 200) => {
           const animationsDisabled = this.hostElement.classList.contains(NO_ANIMATIONS);
           elem.style.transition = '';
-          return animationsDisabled
-              ? this.void$.pipe(tap(() => elem.style[prop] = to))
-              : this.void$.pipe(
-                    // In order to ensure that the `from` value will be applied immediately (i.e.
-                    // without transition) and that the `to` value will be affected by the
-                    // `transition` style, we need to ensure an animation frame has passed between
-                    // setting each style.
-                    switchMap(() => raf$), tap(() => elem.style[prop] = from),
-                    switchMap(() => raf$), tap(() => elem.style.transition = `all ${duration}ms ease-in-out`),
-                    switchMap(() => raf$), tap(() => elem.style[prop] = to),
-                    switchMap(() => timer(getActualDuration(elem))), switchMap(() => this.void$),
-                );
+          return animationsDisabled ?
+              this.void$.pipe(tap(() => elem.style[prop] = to)) :
+              this.void$.pipe(
+                  // In order to ensure that the `from` value will be applied immediately (i.e.
+                  // without transition) and that the `to` value will be affected by the
+                  // `transition` style, we need to ensure an animation frame has passed between
+                  // setting each style.
+                  switchMap(() => raf$),
+                  tap(() => elem.style[prop] = from),
+                  switchMap(() => raf$),
+                  tap(() => elem.style.transition = `all ${duration}ms ease-in-out`),
+                  switchMap(() => raf$),
+                  tap(() => elem.style[prop] = to),
+                  switchMap(() => timer(getActualDuration(elem))),
+                  switchMap(() => this.void$),
+              );
         };
 
     const animateLeave = (elem: HTMLElement) => animateProp(elem, 'opacity', '1', '0.1');
@@ -241,7 +243,8 @@ export class DocViewerComponent implements OnDestroy {
       done$ = done$.pipe(
           // Remove the current view from the viewer.
           switchMap(() => animateLeave(this.currViewContainer)),
-          tap(() => (this.currViewContainer.parentElement as HTMLElement).removeChild(this.currViewContainer)),
+          tap(() => (this.currViewContainer.parentElement as HTMLElement)
+                        .removeChild(this.currViewContainer)),
           tap(() => this.docRemoved.emit()),
       );
     }
@@ -304,7 +307,8 @@ async function printSwDebugInfo(): Promise<void> {
       }
       console.log(await res.text());
     } catch (err) {
-      console.log(`Failed to retrieve debug info from '/ngsw/state': ${err.message || err}`);
+      console.log(
+          `Failed to retrieve debug info from '/ngsw/state': ${(err as Error).message || err}`);
     }
   }
 
@@ -319,25 +323,25 @@ async function printSwDebugInfo(): Promise<void> {
     }
   }
 
-  async function getCacheEntries(
-      name: string, includeValues: boolean,
-      ignoredKeys: string[] = []): Promise<{key: string, value?: unknown}[]> {
+  async function getCacheEntries(name: string, includeValues: boolean, ignoredKeys: string[] = []):
+      Promise<{key: string, value?: unknown}[]> {
     const ignoredUrls = new Set(ignoredKeys.map(key => new Request(key).url));
 
     const cache = await caches.open(name);
     const keys = (await cache.keys()).map(req => req.url).filter(url => !ignoredUrls.has(url));
-    const entries = await Promise.all(keys.map(async key => ({
-      key,
-      value: !includeValues ? undefined : await (await cache.match(key))?.json(),
-    })));
+    const entries = await Promise.all(
+        keys.map(async key => ({
+                   key,
+                   value: !includeValues ? undefined : await (await cache.match(key))?.json(),
+                 })));
 
     return entries;
   }
 
   function printCacheEntries(name: string, entries: {key: string, value?: unknown}[]): void {
-    const entriesStr = entries
-        .map(({key, value}) => `  - ${key}${!value ? '' : `: ${JSON.stringify(value)}`}`)
-        .join('\n');
+    const entriesStr =
+        entries.map(({key, value}) => `  - ${key}${!value ? '' : `: ${JSON.stringify(value)}`}`)
+            .join('\n');
 
     console.log(`\nCache: ${name} (${entries.length} entries)\n${entriesStr}`);
   }
diff --git a/aio/tools/firebase-test-utils/FirebaseRedirectSource.ts b/aio/tools/firebase-test-utils/FirebaseRedirectSource.ts
index 94ba1196e95..5a963535a0e 100644
--- a/aio/tools/firebase-test-utils/FirebaseRedirectSource.ts
+++ b/aio/tools/firebase-test-utils/FirebaseRedirectSource.ts
@@ -2,7 +2,7 @@ import * as XRegExp from 'xregexp';
 
 // The `XRegExp` typings are not accurate.
 interface XRegExp extends RegExp {
-  xregexp: { captureNames?: string[] };
+  xregexp: {captureNames?: string[]};
 }
 
 export class FirebaseRedirectSource {
@@ -22,34 +22,36 @@ export class FirebaseRedirectSource {
   static fromGlobPattern(glob: string): FirebaseRedirectSource {
     const dot = /\./g;
     const star = /\*/g;
-    const doubleStar = /(^|\/)\*\*($|\/)/g;           // e.g. a/**/b or **/b or a/** but not a**b
-    const modifiedPatterns = /(.)\(([^)]+)\)/g;       // e.g. `@(a|b)
-    const restParam = /(\/?):([A-Za-z]+)\*/g;            // e.g. `:rest*`
-    const namedParam = /(\/?):([A-Za-z]+)/g;             // e.g. `:api`
+    const doubleStar = /(^|\/)\*\*($|\/)/g;             // e.g. a/**/b or **/b or a/** but not a**b
+    const modifiedPatterns = /(.)\(([^)]+)\)/g;         // e.g. `@(a|b)
+    const restParam = /(\/?):([A-Za-z]+)\*/g;           // e.g. `:rest*`
+    const namedParam = /(\/?):([A-Za-z]+)/g;            // e.g. `:api`
     const possiblyEmptyInitialSegments = /^\.🐷\//g;  // e.g. `**/a` can also match `a`
     const possiblyEmptySegments = /\/\.🐷\//g;        // e.g. `a/**/b` can also match `a/b`
     const willBeStar = /🐷/g;                         // e.g. `a**b` not matched by previous rule
 
     try {
       const restNamedGroups: string[] = [];
-      const pattern = glob
-          .replace(dot, '\\.')
-          .replace(modifiedPatterns, replaceModifiedPattern)
-          .replace(restParam, (_, leadingSlash, groupName) => {
-            // capture the rest of the string
-            restNamedGroups.push(groupName);
-            return `(?:${leadingSlash}(?<${groupName}>.🐷))?`;
-          })
-          .replace(namedParam, '$1(?<$2>[^/]+)')
-          .replace(doubleStar, '$1.🐷$2')                 // use the pig to avoid replacing ** in next rule
-          .replace(star, '[^/]*')                         // match a single segment
-          .replace(possiblyEmptyInitialSegments, '(?:.*)')// deal with **/ special cases
-          .replace(possiblyEmptySegments, '(?:/|/.*/)')   // deal with /**/ special cases
-          .replace(willBeStar, '*');                      // other ** matches
+      const pattern =
+          glob.replace(dot, '\\.')
+              .replace(modifiedPatterns, replaceModifiedPattern)
+              .replace(
+                  restParam,
+                  (_, leadingSlash, groupName) => {
+                    // capture the rest of the string
+                    restNamedGroups.push(groupName);
+                    return `(?:${leadingSlash}(?<${groupName}>.🐷))?`;
+                  })
+              .replace(namedParam, '$1(?<$2>[^/]+)')
+              .replace(doubleStar, '$1.🐷$2')  // use the pig to avoid replacing ** in next rule
+              .replace(star, '[^/]*')         // match a single segment
+              .replace(possiblyEmptyInitialSegments, '(?:.*)')  // deal with **/ special cases
+              .replace(possiblyEmptySegments, '(?:/|/.*/)')     // deal with /**/ special cases
+              .replace(willBeStar, '*');                        // other ** matches
 
       return new FirebaseRedirectSource(`^${pattern}$`, restNamedGroups);
     } catch (err) {
-      throw new Error(`Error in FirebaseRedirectSource: "${glob}" - ${err.message}`);
+      throw new Error(`Error in FirebaseRedirectSource: "${glob}" - ${(err as Error).message}`);
     }
   }
 
@@ -72,7 +74,7 @@ export class FirebaseRedirectSource {
       // capture groups.
       return new FirebaseRedirectSource(regex.replace(/(\(\?)P(<[^>]+>)/g, '$1$2'));
     } catch (err) {
-      throw new Error(`Error in FirebaseRedirectSource: "${regex}" - ${err.message}`);
+      throw new Error(`Error in FirebaseRedirectSource: "${regex}" - ${(err as Error).message}`);
     }
   }
 
@@ -80,14 +82,14 @@ export class FirebaseRedirectSource {
     return XRegExp.test(url, this.regex);
   }
 
-  match(url: string): { [key: string]: string } | undefined {
+  match(url: string): {[key: string]: string}|undefined {
     const match = XRegExp.exec(url, this.regex) as ReturnType<typeof XRegExp.exec>;
 
     if (!match) {
       return undefined;
     }
 
-    const result: { [key: string]: string } = {};
+    const result: {[key: string]: string} = {};
     const names = this.regex.xregexp.captureNames || [];
     // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
     names.forEach(name => result[name] = match.groups![name]);
diff --git a/aio/tsconfig.json b/aio/tsconfig.json
index 2f2071674f3..dca80c00f18 100644
--- a/aio/tsconfig.json
+++ b/aio/tsconfig.json
@@ -14,7 +14,6 @@
     "noFallthroughCasesInSwitch": true,
     "noUnusedLocals": true,
     "noUnusedParameters": true,
-    "useUnknownInCatchVariables": false,
     "sourceMap": true,
     "declaration": false,
     "downlevelIteration": true,
@@ -47,4 +46,4 @@
     "strictInputAccessModifiers": true,
     "strictTemplates": true
   }
-}
+}
\ No newline at end of file
diff --git a/packages/animations/browser/test/render/transition_animation_engine_spec.ts b/packages/animations/browser/test/render/transition_animation_engine_spec.ts
index 2283fe4d581..8bf274edc51 100644
--- a/packages/animations/browser/test/render/transition_animation_engine_spec.ts
+++ b/packages/animations/browser/test/render/transition_animation_engine_spec.ts
@@ -636,7 +636,7 @@ describe('TransitionAnimationEngine', () => {
       try {
         engine.flush();
       } catch (e) {
-        errorMessage = e.toString();
+        errorMessage = (e as Error).toString();
       }
 
       expect(errorMessage).toMatch(/Unable to animate due to the following errors:/);
diff --git a/packages/common/http/testing/test/request_spec.ts b/packages/common/http/testing/test/request_spec.ts
index 0f3679a2e51..4c468297bd2 100644
--- a/packages/common/http/testing/test/request_spec.ts
+++ b/packages/common/http/testing/test/request_spec.ts
@@ -39,7 +39,7 @@ describe('HttpClient TestRequest', () => {
       mock.expectOne('/some-url').flush(null);
       fail();
     } catch (error) {
-      expect(error.message)
+      expect((error as Error).message)
           .toBe(
               'Expected one matching request for criteria "Match URL: /some-url", found none.' +
               ' Requests received are: GET /some-other-url.');
@@ -61,7 +61,7 @@ describe('HttpClient TestRequest', () => {
       mock.expectOne('/some-url?query=world').flush(null);
       fail();
     } catch (error) {
-      expect(error.message)
+      expect((error as Error).message)
           .toBe(
               'Expected one matching request for criteria "Match URL: /some-url?query=world", found none.' +
               ' Requests received are: GET /some-url?query=hello.');
@@ -85,7 +85,7 @@ describe('HttpClient TestRequest', () => {
       mock.expectOne('/some-url').flush(null);
       fail();
     } catch (error) {
-      expect(error.message)
+      expect((error as Error).message)
           .toBe(
               'Expected one matching request for criteria "Match URL: /some-url", found none.' +
               ' Requests received are: GET /some-other-url?query=world, POST /and-another-url.');
diff --git a/packages/common/src/pipes/date_pipe.ts b/packages/common/src/pipes/date_pipe.ts
index 5c8b958239c..088a9fcc216 100644
--- a/packages/common/src/pipes/date_pipe.ts
+++ b/packages/common/src/pipes/date_pipe.ts
@@ -7,7 +7,9 @@
  */
 
 import {Inject, InjectionToken, LOCALE_ID, Optional, Pipe, PipeTransform} from '@angular/core';
+
 import {formatDate} from '../i18n/format_date';
+
 import {invalidPipeArgumentError} from './invalid_pipe_argument_error';
 
 /**
@@ -209,7 +211,7 @@ export class DatePipe implements PipeTransform {
       return formatDate(
           value, format, locale || this.locale, timezone ?? this.defaultTimezone ?? undefined);
     } catch (error) {
-      throw invalidPipeArgumentError(DatePipe, error.message);
+      throw invalidPipeArgumentError(DatePipe, (error as Error).message);
     }
   }
 }
diff --git a/packages/common/src/pipes/number_pipe.ts b/packages/common/src/pipes/number_pipe.ts
index 97899105375..fd379910d2a 100644
--- a/packages/common/src/pipes/number_pipe.ts
+++ b/packages/common/src/pipes/number_pipe.ts
@@ -7,6 +7,7 @@
  */
 
 import {DEFAULT_CURRENCY_CODE, Inject, LOCALE_ID, Pipe, PipeTransform} from '@angular/core';
+
 import {formatCurrency, formatNumber, formatPercent} from '../i18n/format_number';
 import {getCurrencySymbol} from '../i18n/locale_data_api';
 
@@ -100,7 +101,7 @@ export class DecimalPipe implements PipeTransform {
       const num = strToNumber(value);
       return formatNumber(num, locale, digitsInfo);
     } catch (error) {
-      throw invalidPipeArgumentError(DecimalPipe, error.message);
+      throw invalidPipeArgumentError(DecimalPipe, (error as Error).message);
     }
   }
 }
@@ -156,7 +157,7 @@ export class PercentPipe implements PipeTransform {
       const num = strToNumber(value);
       return formatPercent(num, locale, digitsInfo);
     } catch (error) {
-      throw invalidPipeArgumentError(PercentPipe, error.message);
+      throw invalidPipeArgumentError(PercentPipe, (error as Error).message);
     }
   }
 }
@@ -281,7 +282,7 @@ export class CurrencyPipe implements PipeTransform {
       const num = strToNumber(value);
       return formatCurrency(num, locale, currency, currencyCode, digitsInfo);
     } catch (error) {
-      throw invalidPipeArgumentError(CurrencyPipe, error.message);
+      throw invalidPipeArgumentError(CurrencyPipe, (error as Error).message);
     }
   }
 }
diff --git a/packages/common/upgrade/src/location_shim.ts b/packages/common/upgrade/src/location_shim.ts
index 4e46269a06c..274eb00a634 100644
--- a/packages/common/upgrade/src/location_shim.ts
+++ b/packages/common/upgrade/src/location_shim.ts
@@ -360,7 +360,7 @@ export class $locationShim {
       try {
         fn(url, state, oldUrl, oldState);
       } catch (e) {
-        err(e);
+        err(e as Error);
       }
     });
   }
diff --git a/packages/compiler-cli/linker/babel/src/es2015_linker_plugin.ts b/packages/compiler-cli/linker/babel/src/es2015_linker_plugin.ts
index cfe97b67100..b742d991fb5 100644
--- a/packages/compiler-cli/linker/babel/src/es2015_linker_plugin.ts
+++ b/packages/compiler-cli/linker/babel/src/es2015_linker_plugin.ts
@@ -92,7 +92,7 @@ export function createEs2015LinkerPlugin({fileSystem, logger, ...options}: Linke
           call.replaceWith(replacement);
         } catch (e) {
           const node = isFatalLinkerError(e) ? e.node as t.Node : call.node;
-          throw buildCodeFrameError(call.hub.file, e.message, node);
+          throw buildCodeFrameError(call.hub.file, (e as Error).message, node);
         }
       }
     }
diff --git a/packages/compiler-cli/ngcc/main-ngcc.ts b/packages/compiler-cli/ngcc/main-ngcc.ts
index a320fcffb63..fdfbb77c143 100644
--- a/packages/compiler-cli/ngcc/main-ngcc.ts
+++ b/packages/compiler-cli/ngcc/main-ngcc.ts
@@ -21,8 +21,8 @@ const options = parseCommandLineOptions(process.argv.slice(2));
       options.logger.debug(`Run ngcc in ${duration}s.`);
     }
     process.exitCode = 0;
-  } catch (e) {
-    console.error(e.stack || e.message);
+  } catch (e: any) {
+    console.error((e as Error).stack || (e as Error).message);
     process.exit(typeof e.code === 'number' ? e.code : 1);
   }
 })();
diff --git a/packages/compiler-cli/ngcc/src/execution/cluster/ngcc_cluster_worker.ts b/packages/compiler-cli/ngcc/src/execution/cluster/ngcc_cluster_worker.ts
index a7072fecaa8..2714ec6e88e 100644
--- a/packages/compiler-cli/ngcc/src/execution/cluster/ngcc_cluster_worker.ts
+++ b/packages/compiler-cli/ngcc/src/execution/cluster/ngcc_cluster_worker.ts
@@ -40,7 +40,7 @@ import {startWorker} from './worker';
     await startWorker(logger, createCompileFn);
     process.exitCode = 0;
   } catch (e) {
-    console.error(e.stack || e.message);
+    console.error((e as Error).stack || (e as Error).message);
     process.exit(1);
   }
 })();
diff --git a/packages/compiler-cli/ngcc/src/execution/cluster/worker.ts b/packages/compiler-cli/ngcc/src/execution/cluster/worker.ts
index 263e16d0907..81f2946183a 100644
--- a/packages/compiler-cli/ngcc/src/execution/cluster/worker.ts
+++ b/packages/compiler-cli/ngcc/src/execution/cluster/worker.ts
@@ -40,7 +40,7 @@ export async function startWorker(logger: Logger, createCompileFn: CreateCompile
           throw new Error(
               `[Worker #${cluster.worker.id}] Invalid message received: ${JSON.stringify(msg)}`);
       }
-    } catch (err) {
+    } catch (err: any) {
       switch (err && err.code) {
         case 'ENOMEM':
           // Not being able to allocate enough memory is not necessarily a problem with processing
diff --git a/packages/compiler-cli/ngcc/src/locking/async_locker.ts b/packages/compiler-cli/ngcc/src/locking/async_locker.ts
index 7e2f1dc7aad..61d7a6fffee 100644
--- a/packages/compiler-cli/ngcc/src/locking/async_locker.ts
+++ b/packages/compiler-cli/ngcc/src/locking/async_locker.ts
@@ -49,7 +49,7 @@ export class AsyncLocker {
     for (let attempts = 0; attempts < this.retryAttempts; attempts++) {
       try {
         return this.lockFile.write();
-      } catch (e) {
+      } catch (e: any) {
         if (e.code !== 'EEXIST') {
           throw e;
         }
diff --git a/packages/compiler-cli/ngcc/src/locking/lock_file_with_child_process/util.ts b/packages/compiler-cli/ngcc/src/locking/lock_file_with_child_process/util.ts
index d4870221b24..a80c85a77f6 100644
--- a/packages/compiler-cli/ngcc/src/locking/lock_file_with_child_process/util.ts
+++ b/packages/compiler-cli/ngcc/src/locking/lock_file_with_child_process/util.ts
@@ -26,7 +26,7 @@ export function removeLockFile(
       logger.debug(
           `PIDs do not match (${pid} and ${lockFilePid}), so not removing ${lockFilePath}.`);
     }
-  } catch (e) {
+  } catch (e: any) {
     if (e.code === 'ENOENT') {
       logger.debug(`The lock-file at ${lockFilePath} was already removed.`);
       // File already removed so quietly exit
diff --git a/packages/compiler-cli/ngcc/src/locking/sync_locker.ts b/packages/compiler-cli/ngcc/src/locking/sync_locker.ts
index 54cca4d4a51..51459fbad05 100644
--- a/packages/compiler-cli/ngcc/src/locking/sync_locker.ts
+++ b/packages/compiler-cli/ngcc/src/locking/sync_locker.ts
@@ -39,7 +39,7 @@ export class SyncLocker {
   protected create(): void {
     try {
       this.lockFile.write();
-    } catch (e) {
+    } catch (e: any) {
       if (e.code !== 'EEXIST') {
         throw e;
       }
diff --git a/packages/compiler-cli/ngcc/src/packages/configuration.ts b/packages/compiler-cli/ngcc/src/packages/configuration.ts
index 13f3c857534..0b7c8a674c7 100644
--- a/packages/compiler-cli/ngcc/src/packages/configuration.ts
+++ b/packages/compiler-cli/ngcc/src/packages/configuration.ts
@@ -415,7 +415,8 @@ export class NgccConfiguration {
       try {
         return this.evalSrcFile(configFilePath);
       } catch (e) {
-        throw new Error(`Invalid project configuration file at "${configFilePath}": ` + e.message);
+        throw new Error(
+            `Invalid project configuration file at "${configFilePath}": ` + (e as Error).message);
       }
     } else {
       return {packages: {}};
@@ -433,7 +434,8 @@ export class NgccConfiguration {
           versionRange: version || '*',
         };
       } catch (e) {
-        throw new Error(`Invalid package configuration file at "${configFilePath}": ` + e.message);
+        throw new Error(
+            `Invalid package configuration file at "${configFilePath}": ` + (e as Error).message);
       }
     } else {
       return null;
diff --git a/packages/compiler-cli/ngcc/src/packages/entry_point_manifest.ts b/packages/compiler-cli/ngcc/src/packages/entry_point_manifest.ts
index 1bf23464b51..e708955e2a8 100644
--- a/packages/compiler-cli/ngcc/src/packages/entry_point_manifest.ts
+++ b/packages/compiler-cli/ngcc/src/packages/entry_point_manifest.ts
@@ -95,7 +95,8 @@ export class EntryPointManifest {
       return entryPoints;
     } catch (e) {
       this.logger.warn(
-          `Unable to read the entry-point manifest for ${basePath}:\n`, e.stack || e.toString());
+          `Unable to read the entry-point manifest for ${basePath}:\n`,
+          (e as Error).stack || (e as Error).toString());
       return null;
     }
   }
diff --git a/packages/compiler-cli/ngcc/src/rendering/source_maps.ts b/packages/compiler-cli/ngcc/src/rendering/source_maps.ts
index 59098e45ddf..4c6c744414e 100644
--- a/packages/compiler-cli/ngcc/src/rendering/source_maps.ts
+++ b/packages/compiler-cli/ngcc/src/rendering/source_maps.ts
@@ -64,7 +64,7 @@ export function renderSourceAndMap(
     ];
   } catch (e) {
     logger.error(`Error when flattening the source-map "${sourceMapPath}" for "${
-        sourceFilePath}": ${e.toString()}`);
+        sourceFilePath}": ${(e as Error).toString()}`);
     return [
       {path: sourceFilePath, contents: generatedContent},
       {path: sourceMapPath, contents: mapHelpers.fromObject(generatedMap).toJSON()},
diff --git a/packages/compiler-cli/ngcc/src/writing/new_entry_point_file_writer.ts b/packages/compiler-cli/ngcc/src/writing/new_entry_point_file_writer.ts
index ea40506334d..cf5cc3e0581 100644
--- a/packages/compiler-cli/ngcc/src/writing/new_entry_point_file_writer.ts
+++ b/packages/compiler-cli/ngcc/src/writing/new_entry_point_file_writer.ts
@@ -113,7 +113,7 @@ export class NewEntryPointFileWriter extends InPlaceFileWriter {
         this.fs.writeFile(newSourceMapPath, JSON.stringify(sourceMap));
       } catch (e) {
         this.logger.warn(`Failed to process source-map at ${sourceMapPath}`);
-        this.logger.warn(e.message ?? e);
+        this.logger.warn((e as Error).message ?? e);
       }
     }
   }
diff --git a/packages/compiler-cli/ngcc/test/execution/cluster/executor_spec.ts b/packages/compiler-cli/ngcc/test/execution/cluster/executor_spec.ts
index 0741c4e6bb5..32e6cfd0de0 100644
--- a/packages/compiler-cli/ngcc/test/execution/cluster/executor_spec.ts
+++ b/packages/compiler-cli/ngcc/test/execution/cluster/executor_spec.ts
@@ -86,7 +86,7 @@ runInEachFileSystem(() => {
         try {
           await executor.execute(analyzeEntryPointsSpy, createCompilerFnSpy);
         } catch (e) {
-          error = e.message;
+          error = (e as Error).message;
         }
         expect(analyzeEntryPointsSpy).toHaveBeenCalledWith();
         expect(createCompilerFnSpy).not.toHaveBeenCalled();
@@ -101,7 +101,7 @@ runInEachFileSystem(() => {
         try {
           await executor.execute(anyFn, anyFn);
         } catch (e) {
-          error = e.message;
+          error = (e as Error).message;
         }
         expect(error).toEqual('master runner error');
         expect(lockFileLog).toEqual(['write()', 'remove()']);
@@ -121,7 +121,7 @@ runInEachFileSystem(() => {
         try {
           await executor.execute(anyFn, anyFn);
         } catch (e) {
-          error = e.message;
+          error = (e as Error).message;
         }
         expect(error).toEqual('LockFile.write() error');
         expect(masterRunSpy).not.toHaveBeenCalled();
@@ -141,7 +141,7 @@ runInEachFileSystem(() => {
         try {
           await executor.execute(anyFn, anyFn);
         } catch (e) {
-          error = e.message;
+          error = (e as Error).message;
         }
         expect(error).toEqual('LockFile.remove() error');
         expect(lockFileLog).toEqual(['write()', 'remove()']);
diff --git a/packages/compiler-cli/ngcc/test/execution/single_processor_executor_spec.ts b/packages/compiler-cli/ngcc/test/execution/single_processor_executor_spec.ts
index 81ff7a1ac2e..5f365949654 100644
--- a/packages/compiler-cli/ngcc/test/execution/single_processor_executor_spec.ts
+++ b/packages/compiler-cli/ngcc/test/execution/single_processor_executor_spec.ts
@@ -65,7 +65,7 @@ describe('SingleProcessExecutor', () => {
       try {
         executor.execute(errorFn, createCompileFn);
       } catch (e) {
-        error = e.message;
+        error = (e as Error).message;
       }
       expect(error).toEqual('analyze error');
       expect(lockFileLog).toEqual(['write()', 'remove()']);
@@ -79,7 +79,7 @@ describe('SingleProcessExecutor', () => {
       try {
         executor.execute(oneTask, createErrorCompileFn);
       } catch (e) {
-        error = e.message;
+        error = (e as Error).message;
       }
       expect(error).toEqual('compile error');
       expect(lockFileLog).toEqual(['write()', 'remove()']);
@@ -100,7 +100,7 @@ describe('SingleProcessExecutor', () => {
       try {
         executor.execute(analyzeFn, anyFn);
       } catch (e) {
-        error = e.message;
+        error = (e as Error).message;
       }
       expect(error).toEqual('LockFile.write() error');
       expect(lockFileLog).toEqual(['write()']);
@@ -118,7 +118,7 @@ describe('SingleProcessExecutor', () => {
       try {
         executor.execute(noTasks, anyFn);
       } catch (e) {
-        error = e.message;
+        error = (e as Error).message;
       }
       expect(error).toEqual('LockFile.remove() error');
       expect(lockFileLog).toEqual(['write()', 'remove()']);
diff --git a/packages/compiler-cli/ngcc/test/integration/ngcc_spec.ts b/packages/compiler-cli/ngcc/test/integration/ngcc_spec.ts
index 29d5a6311e5..721f45e14b8 100644
--- a/packages/compiler-cli/ngcc/test/integration/ngcc_spec.ts
+++ b/packages/compiler-cli/ngcc/test/integration/ngcc_spec.ts
@@ -1587,7 +1587,7 @@ runInEachFileSystem(() => {
              propertiesToConsider: ['esm2015', 'esm5'],
            });
            fail('should have thrown');
-         } catch (e) {
+         } catch (e: any) {
            expect(e.message).toContain(
                'Failed to compile entry-point test-package (`esm2015` as esm2015) due to compilation errors:');
            expect(e.message).toContain('NG1010');
@@ -2889,7 +2889,7 @@ runInEachFileSystem(() => {
                propertiesToConsider: ['es2015']
              });
              fail('should have thrown');
-           } catch (e) {
+           } catch (e: any) {
              expect(e.message).toContain(
                  'Failed to compile entry-point fatal-error (`es2015` as esm2015) due to compilation errors:');
              expect(e.message).toContain('NG2001');
diff --git a/packages/compiler-cli/ngcc/test/locking/async_locker_spec.ts b/packages/compiler-cli/ngcc/test/locking/async_locker_spec.ts
index cfee2cfd010..28812124cbb 100644
--- a/packages/compiler-cli/ngcc/test/locking/async_locker_spec.ts
+++ b/packages/compiler-cli/ngcc/test/locking/async_locker_spec.ts
@@ -44,7 +44,7 @@ runInEachFileSystem(() => {
                throw new Error('ERROR');
              });
            } catch (e) {
-             error = e.message;
+             error = (e as Error).message;
            }
            expect(error).toEqual('ERROR');
            expect(log).toEqual(['write()', 'fn()', 'remove()']);
diff --git a/packages/compiler-cli/ngcc/test/locking/sync_locker_spec.ts b/packages/compiler-cli/ngcc/test/locking/sync_locker_spec.ts
index b1445c40857..d8d7952b34e 100644
--- a/packages/compiler-cli/ngcc/test/locking/sync_locker_spec.ts
+++ b/packages/compiler-cli/ngcc/test/locking/sync_locker_spec.ts
@@ -38,7 +38,7 @@ runInEachFileSystem(() => {
                throw new Error('ERROR');
              });
            } catch (e) {
-             error = e.message;
+             error = (e as Error).message;
            }
            expect(error).toEqual('ERROR');
            expect(log).toEqual(['write()', 'fn()', 'remove()']);
diff --git a/packages/compiler-cli/src/ngtsc/sourcemaps/src/source_file_loader.ts b/packages/compiler-cli/src/ngtsc/sourcemaps/src/source_file_loader.ts
index b0d1016fe01..7e920929903 100644
--- a/packages/compiler-cli/src/ngtsc/sourcemaps/src/source_file_loader.ts
+++ b/packages/compiler-cli/src/ngtsc/sourcemaps/src/source_file_loader.ts
@@ -111,7 +111,7 @@ export class SourceFileLoader {
       return new SourceFile(sourcePath, contents, sourceMapInfo, sources, this.fs);
     } catch (e) {
       this.logger.warn(
-          `Unable to fully load ${sourcePath} for source-map flattening: ${e.message}`);
+          `Unable to fully load ${sourcePath} for source-map flattening: ${(e as Error).message}`);
       return null;
     } finally {
       // We are finished with this recursion so revert the paths being tracked
@@ -166,8 +166,8 @@ export class SourceFileLoader {
           origin: ContentOrigin.FileSystem,
         };
       } catch (e) {
-        this.logger.warn(
-            `Unable to fully load ${sourcePath} for source-map flattening: ${e.message}`);
+        this.logger.warn(`Unable to fully load ${sourcePath} for source-map flattening: ${
+            (e as Error).message}`);
         return null;
       }
     }
diff --git a/packages/compiler-cli/src/ngtsc/testing/src/mock_file_loading.ts b/packages/compiler-cli/src/ngtsc/testing/src/mock_file_loading.ts
index 63c86058b42..53804633ed9 100644
--- a/packages/compiler-cli/src/ngtsc/testing/src/mock_file_loading.ts
+++ b/packages/compiler-cli/src/ngtsc/testing/src/mock_file_loading.ts
@@ -12,6 +12,7 @@ import {resolve} from 'path';
 
 import {AbsoluteFsPath, FileSystem, getFileSystem} from '../../file_system';
 import {Folder, MockFileSystemPosix, TestFile} from '../../file_system/testing';
+
 import {getAngularPackagesFromRunfiles, resolveNpmTreeArtifact} from './runfile_helpers';
 
 export function loadTestFiles(files: TestFile[]) {
@@ -132,7 +133,7 @@ export function loadTestDirectory(
         fs.writeFile(targetPath, readFileSync(srcPath, 'utf-8'));
       }
     } catch (e) {
-      console.warn(`Failed to add ${srcPath} to the mock file-system: ${e.message}`);
+      console.warn(`Failed to add ${srcPath} to the mock file-system: ${(e as Error).message}`);
     }
   });
 }
diff --git a/packages/compiler-cli/src/perform_compile.ts b/packages/compiler-cli/src/perform_compile.ts
index 87c97652b7e..e6f23f51b3d 100644
--- a/packages/compiler-cli/src/perform_compile.ts
+++ b/packages/compiler-cli/src/perform_compile.ts
@@ -133,7 +133,7 @@ export function readConfiguration(
   } catch (e) {
     const errors: ts.Diagnostic[] = [{
       category: ts.DiagnosticCategory.Error,
-      messageText: e.stack,
+      messageText: (e as Error).stack ?? (e as Error).message,
       file: undefined,
       start: undefined,
       length: undefined,
@@ -267,7 +267,7 @@ export function performCompilation({
     program = undefined;
     allDiagnostics.push({
       category: ts.DiagnosticCategory.Error,
-      messageText: e.stack,
+      messageText: (e as Error).stack ?? (e as Error).message,
       code: api.UNKNOWN_ERROR_CODE,
       file: undefined,
       start: undefined,
diff --git a/packages/compiler-cli/test/compliance/test_helpers/get_compliance_tests.ts b/packages/compiler-cli/test/compliance/test_helpers/get_compliance_tests.ts
index e4747947063..f1ecd56e4e5 100644
--- a/packages/compiler-cli/test/compliance/test_helpers/get_compliance_tests.ts
+++ b/packages/compiler-cli/test/compliance/test_helpers/get_compliance_tests.ts
@@ -59,8 +59,8 @@ function loadTestCasesFile(
   try {
     return JSON.parse(fs.readFile(testCasesPath)) as {cases: TestCaseJson | TestCaseJson[]};
   } catch (e) {
-    throw new Error(
-        `Failed to load test-cases at "${fs.relative(basePath, testCasesPath)}":\n ${e.message}`);
+    throw new Error(`Failed to load test-cases at "${fs.relative(basePath, testCasesPath)}":\n ${
+        (e as Error).message}`);
   }
 }
 
diff --git a/packages/compiler-cli/test/test_support.ts b/packages/compiler-cli/test/test_support.ts
index e0dff2785bf..b724ff89783 100644
--- a/packages/compiler-cli/test/test_support.ts
+++ b/packages/compiler-cli/test/test_support.ts
@@ -142,7 +142,7 @@ export function setupBazelTo(tmpDirPath: string) {
     const rxjsSource = resolveNpmTreeArtifact('rxjs', 'index.js');
     const rxjsDest = path.join(nodeModulesPath, 'rxjs');
     fs.symlinkSync(rxjsSource, rxjsDest, 'junction');
-  } catch (e) {
+  } catch (e: any) {
     if (e.code !== 'MODULE_NOT_FOUND') throw e;
   }
 }
diff --git a/packages/core/schematics/tsconfig.json b/packages/core/schematics/tsconfig.json
index 19f7b0654d7..dbeb0be6f63 100644
--- a/packages/core/schematics/tsconfig.json
+++ b/packages/core/schematics/tsconfig.json
@@ -2,23 +2,34 @@
   "compilerOptions": {
     "noImplicitReturns": true,
     "noImplicitOverride": true,
-    "useUnknownInCatchVariables": false,
     "noFallthroughCasesInSwitch": true,
     "esModuleInterop": true,
     "strict": true,
     "moduleResolution": "node",
     "target": "es2019",
-    "lib": ["es2019"],
-    "types": ["jasmine"],
+    "lib": [
+      "es2019"
+    ],
+    "types": [
+      "jasmine"
+    ],
     "baseUrl": ".",
     "paths": {
-      "@angular/core": ["../"],
-      "@angular/compiler": ["../../compiler"],
-      "@angular/compiler-cli": ["../../compiler-cli"],
-      "@angular/compiler-cli/private/*": ["../../compiler-cli/private/*"]
+      "@angular/core": [
+        "../"
+      ],
+      "@angular/compiler": [
+        "../../compiler"
+      ],
+      "@angular/compiler-cli": [
+        "../../compiler-cli"
+      ],
+      "@angular/compiler-cli/private/*": [
+        "../../compiler-cli/private/*"
+      ]
     }
   },
   "bazelOptions": {
     "suppressTsconfigOverrideWarnings": true
   }
-}
+}
\ No newline at end of file
diff --git a/packages/core/src/di/r3_injector.ts b/packages/core/src/di/r3_injector.ts
index 641a348dcf8..48c36dfbe6b 100644
--- a/packages/core/src/di/r3_injector.ts
+++ b/packages/core/src/di/r3_injector.ts
@@ -222,7 +222,7 @@ export class R3Injector {
           null :
           notFoundValue;
       return nextInjector.get(token, notFoundValue);
-    } catch (e) {
+    } catch (e: any) {
       if (e.name === 'NullInjectorError') {
         const path: any[] = e[NG_TEMP_TOKEN_PATH] = e[NG_TEMP_TOKEN_PATH] || [];
         path.unshift(stringify(token));
diff --git a/packages/core/src/di/reflective_injector.ts b/packages/core/src/di/reflective_injector.ts
index 64b72a21055..031b68a1aca 100644
--- a/packages/core/src/di/reflective_injector.ts
+++ b/packages/core/src/di/reflective_injector.ts
@@ -362,7 +362,7 @@ export class ReflectiveInjector_ implements ReflectiveInjector {
     try {
       deps =
           ResolvedReflectiveFactory.dependencies.map(dep => this._getByReflectiveDependency(dep));
-    } catch (e) {
+    } catch (e: any) {
       if (e.addKey) {
         e.addKey(this, provider.key);
       }
@@ -373,7 +373,7 @@ export class ReflectiveInjector_ implements ReflectiveInjector {
     try {
       obj = factory(...deps);
     } catch (e) {
-      throw instantiationError(this, e, e.stack, provider.key);
+      throw instantiationError(this, e, (e as Error).stack, provider.key);
     }
 
     return obj;
diff --git a/packages/core/test/animation/animation_integration_spec.ts b/packages/core/test/animation/animation_integration_spec.ts
index 52b1337888b..5b126bba3f3 100644
--- a/packages/core/test/animation/animation_integration_spec.ts
+++ b/packages/core/test/animation/animation_integration_spec.ts
@@ -3843,7 +3843,7 @@ describe('animation tests', function() {
        try {
          fixture.detectChanges();
        } catch (e) {
-         errorMsg = e.message;
+         errorMsg = (e as Error).message;
        }
 
        expect(errorMsg).toMatch(/@foo has failed due to:/);
diff --git a/packages/core/test/compiler/compiler_facade_spec.ts b/packages/core/test/compiler/compiler_facade_spec.ts
index 6878c86442e..399a3301a20 100644
--- a/packages/core/test/compiler/compiler_facade_spec.ts
+++ b/packages/core/test/compiler/compiler_facade_spec.ts
@@ -20,8 +20,9 @@ describe('getCompilerFacade', () => {
         getCompilerFacade({usage: JitCompilerUsage.Decorator, kind: 'directive', type: TestClass});
         fail('Error expected as compiler facade is not available');
       } catch (e) {
-        expect(e.message).toEqual(
-            `The directive 'TestClass' needs to be compiled using the JIT compiler, but '@angular/compiler' is not available.
+        expect((e as Error).message)
+            .toEqual(
+                `The directive 'TestClass' needs to be compiled using the JIT compiler, but '@angular/compiler' is not available.
 
 JIT compilation is discouraged for production use-cases! Consider using AOT mode instead.
 Alternatively, the JIT compiler should be loaded by bootstrapping using '@angular/platform-browser-dynamic' or '@angular/platform-server',
@@ -35,8 +36,9 @@ or manually provide the compiler with 'import "@angular/compiler";' before boots
             {usage: JitCompilerUsage.PartialDeclaration, kind: 'directive', type: TestClass});
         fail('Error expected as compiler facade is not available');
       } catch (e) {
-        expect(e.message).toEqual(
-            `The directive 'TestClass' needs to be compiled using the JIT compiler, but '@angular/compiler' is not available.
+        expect((e as Error).message)
+            .toEqual(
+                `The directive 'TestClass' needs to be compiled using the JIT compiler, but '@angular/compiler' is not available.
 
 The directive is part of a library that has been partially compiled.
 However, the Angular Linker has not processed the library such that JIT compilation is used as fallback.
diff --git a/packages/core/test/di/reflective_injector_spec.ts b/packages/core/test/di/reflective_injector_spec.ts
index bc9a21928c4..f51e6cf5009 100644
--- a/packages/core/test/di/reflective_injector_spec.ts
+++ b/packages/core/test/di/reflective_injector_spec.ts
@@ -300,7 +300,7 @@ describe(`injector`, () => {
     try {
       injector.get(Car);
       throw 'Must throw';
-    } catch (e) {
+    } catch (e: any) {
       expect(e.message).toContain(
           `Error during instantiation of Engine! (${stringify(Car)} -> Engine)`);
       expect(getOriginalError(e) instanceof Error).toBeTruthy();
diff --git a/packages/core/test/linker/change_detection_integration_spec.ts b/packages/core/test/linker/change_detection_integration_spec.ts
index 990e9a9e879..a856d46dcb9 100644
--- a/packages/core/test/linker/change_detection_integration_spec.ts
+++ b/packages/core/test/linker/change_detection_integration_spec.ts
@@ -748,7 +748,7 @@ describe(`ChangeDetection`, () => {
            try {
              ctx.detectChanges(false);
            } catch (e) {
-             expect(e.message).toBe('Boom!');
+             expect((e as Error).message).toBe('Boom!');
              errored = true;
            }
            expect(errored).toBe(true);
@@ -760,7 +760,7 @@ describe(`ChangeDetection`, () => {
            try {
              ctx.detectChanges(false);
            } catch (e) {
-             expect(e.message).toBe('Boom!');
+             expect((e as Error).message).toBe('Boom!');
              throw new Error('Second detectChanges() should not have called ngOnInit.');
            }
            expect(directiveLog.filter(['ngOnInit'])).toEqual([]);
diff --git a/packages/core/test/linker/integration_spec.ts b/packages/core/test/linker/integration_spec.ts
index a348d7bf843..aed680db501 100644
--- a/packages/core/test/linker/integration_spec.ts
+++ b/packages/core/test/linker/integration_spec.ts
@@ -1426,8 +1426,8 @@ describe('integration tests', function() {
       try {
         TestBed.createComponent(ComponentWithoutView);
       } catch (e) {
-        expect(e.message).toContain(
-            `No template specified for component ${stringify(ComponentWithoutView)}`);
+        expect((e as Error).message)
+            .toContain(`No template specified for component ${stringify(ComponentWithoutView)}`);
       }
     });
   });
diff --git a/packages/localize/src/translate.ts b/packages/localize/src/translate.ts
index 838df1aedde..2d018d0a6cc 100644
--- a/packages/localize/src/translate.ts
+++ b/packages/localize/src/translate.ts
@@ -93,7 +93,7 @@ export function translate(messageParts: TemplateStringsArray, substitutions: rea
   try {
     return _translate($localize.TRANSLATIONS, messageParts, substitutions);
   } catch (e) {
-    console.warn(e.message);
+    console.warn((e as Error).message);
     return [messageParts, substitutions];
   }
 }
diff --git a/packages/localize/tools/src/source_file_utils.ts b/packages/localize/tools/src/source_file_utils.ts
index 6f43b0a7ba0..1dc5ef8eb70 100644
--- a/packages/localize/tools/src/source_file_utils.ts
+++ b/packages/localize/tools/src/source_file_utils.ts
@@ -374,7 +374,7 @@ export function translate(
     missingTranslation: DiagnosticHandlingStrategy): [TemplateStringsArray, readonly any[]] {
   try {
     return ɵtranslate(translations, messageParts, substitutions);
-  } catch (e) {
+  } catch (e: any) {
     if (ɵisMissingTranslationError(e)) {
       diagnostics.add(missingTranslation, e.message);
       // Return the parsed message because this will have the meta blocks stripped
diff --git a/packages/localize/tools/src/translate/asset_files/asset_translation_handler.ts b/packages/localize/tools/src/translate/asset_files/asset_translation_handler.ts
index 725cc512ad8..17576fd3374 100644
--- a/packages/localize/tools/src/translate/asset_files/asset_translation_handler.ts
+++ b/packages/localize/tools/src/translate/asset_files/asset_translation_handler.ts
@@ -42,7 +42,7 @@ export class AssetTranslationHandler implements TranslationHandler {
       this.fs.ensureDir(this.fs.dirname(outputPath));
       this.fs.writeFile(outputPath, contents);
     } catch (e) {
-      diagnostics.error(e.message);
+      diagnostics.error((e as Error).message);
     }
   }
 }
diff --git a/packages/localize/tools/src/translate/source_files/source_file_translation_handler.ts b/packages/localize/tools/src/translate/source_files/source_file_translation_handler.ts
index 2256042f806..3bd8a9cd7d7 100644
--- a/packages/localize/tools/src/translate/source_files/source_file_translation_handler.ts
+++ b/packages/localize/tools/src/translate/source_files/source_file_translation_handler.ts
@@ -6,8 +6,8 @@
  * found in the LICENSE file at https://angular.io/license
  */
 import {absoluteFrom, AbsoluteFsPath, FileSystem, PathSegment} from '@angular/compiler-cli/private/localize';
-import {parseSync, transformFromAstSync, types as t} from '../../babel_core';
 
+import {parseSync, transformFromAstSync, types as t} from '../../babel_core';
 import {Diagnostics} from '../../diagnostics';
 import {TranslatePluginOptions} from '../../source_file_utils';
 import {OutputPathFn} from '../output_path';
@@ -103,7 +103,7 @@ export class SourceFileTranslationHandler implements TranslationHandler {
       this.fs.ensureDir(this.fs.dirname(outputPath));
       this.fs.writeFile(outputPath, contents);
     } catch (e) {
-      diagnostics.error(e.message);
+      diagnostics.error((e as Error).message);
     }
   }
 }
diff --git a/packages/localize/tools/src/translate/translation_files/translation_parsers/serialize_translation_message.ts b/packages/localize/tools/src/translate/translation_files/translation_parsers/serialize_translation_message.ts
index df247b1801f..9b5b11569fe 100644
--- a/packages/localize/tools/src/translate/translation_files/translation_parsers/serialize_translation_message.ts
+++ b/packages/localize/tools/src/translate/translation_files/translation_parsers/serialize_translation_message.ts
@@ -27,6 +27,6 @@ export function serializeTranslationMessage(element: Element, config: MessageSer
     const translation = serializer.serialize(rootNodes);
     return {translation, parseErrors, serializeErrors: []};
   } catch (e) {
-    return {translation: null, parseErrors, serializeErrors: [e]};
+    return {translation: null, parseErrors, serializeErrors: [e as ParseError]};
   }
 }
diff --git a/packages/misc/angular-in-memory-web-api/src/backend-service.ts b/packages/misc/angular-in-memory-web-api/src/backend-service.ts
index 71a62384ead..6e01ba0bebf 100644
--- a/packages/misc/angular-in-memory-web-api/src/backend-service.ts
+++ b/packages/misc/angular-in-memory-web-api/src/backend-service.ts
@@ -320,7 +320,7 @@ export abstract class BackendService {
       try {
         resOptions = resOptionsFactory();
       } catch (error) {
-        const err = error.message || error;
+        const err = (error as Error).message || error;
         resOptions = this.createErrorResponseOptions('', STATUS.INTERNAL_SERVER_ERROR, `${err}`);
       }
 
@@ -550,7 +550,7 @@ export abstract class BackendService {
       const resourceUrl = urlRoot + apiBase + collectionName + '/';
       return {apiBase, collectionName, id, query, resourceUrl};
     } catch (err) {
-      const msg = `unable to parse url '${url}'; original error: ${err.message}`;
+      const msg = `unable to parse url '${url}'; original error: ${(err as Error).message}`;
       throw new Error(msg);
     }
   }
@@ -565,7 +565,7 @@ export abstract class BackendService {
       try {
         item.id = id || this.genId(collection, collectionName);
       } catch (err) {
-        const emsg: string = err.message || '';
+        const emsg: string = (err as Error).message || '';
         if (/id type is non-numeric/.test(emsg)) {
           return this.createErrorResponseOptions(url, STATUS.UNPROCESSABLE_ENTRY, emsg);
         } else {
@@ -597,7 +597,7 @@ export abstract class BackendService {
     } else {
       collection[existingIx] = item;
       return this.config.post204 ? {headers, status: STATUS.NO_CONTENT} :  // successful; no content
-          {headers, body, status: STATUS.OK};  // successful; return entity
+                                   {headers, body, status: STATUS.OK};  // successful; return entity
     }
   }
 
@@ -621,7 +621,7 @@ export abstract class BackendService {
     if (existingIx > -1) {
       collection[existingIx] = item;
       return this.config.put204 ? {headers, status: STATUS.NO_CONTENT} :  // successful; no content
-          {headers, body, status: STATUS.OK};  // successful; return entity
+                                  {headers, body, status: STATUS.OK};  // successful; return entity
     } else if (this.config.put404) {
       // item to update not found; use POST to create new item for this id.
       return this.createErrorResponseOptions(
@@ -651,9 +651,9 @@ export abstract class BackendService {
   protected resetDb(reqInfo?: RequestInfo): Observable<boolean> {
     this.dbReadySubject && this.dbReadySubject.next(false);
     const db = this.inMemDbService.createDb(reqInfo);
-    const db$ = db instanceof Observable ?
-        db :
-        typeof (db as any).then === 'function' ? from(db as Promise<any>) : of(db);
+    const db$ = db instanceof Observable       ? db :
+        typeof (db as any).then === 'function' ? from(db as Promise<any>) :
+                                                 of(db);
     db$.pipe(first()).subscribe((d: {}) => {
       this.db = d;
       this.dbReadySubject && this.dbReadySubject.next(true);
diff --git a/packages/misc/angular-in-memory-web-api/src/http-client-backend-service.ts b/packages/misc/angular-in-memory-web-api/src/http-client-backend-service.ts
index 92701755bf5..139b4abe154 100644
--- a/packages/misc/angular-in-memory-web-api/src/http-client-backend-service.ts
+++ b/packages/misc/angular-in-memory-web-api/src/http-client-backend-service.ts
@@ -57,7 +57,7 @@ export class HttpClientBackendService extends BackendService implements HttpBack
       return this.handleRequest(req);
 
     } catch (error) {
-      const err = error.message || error;
+      const err = (error as Error).message || error;
       const resOptions =
           this.createErrorResponseOptions(req.url, STATUS.INTERNAL_SERVER_ERROR, `${err}`);
       return this.createResponse$(() => resOptions);
@@ -93,7 +93,7 @@ export class HttpClientBackendService extends BackendService implements HttpBack
   protected override createPassThruBackend() {
     try {
       return new HttpXhrBackend(this.xhrFactory);
-    } catch (ex) {
+    } catch (ex: any) {
       ex.message = 'Cannot create passThru404 backend; ' + (ex.message || '');
       throw ex;
     }
diff --git a/packages/router/src/router.ts b/packages/router/src/router.ts
index 8c984253a7e..8842a0caf12 100644
--- a/packages/router/src/router.ts
+++ b/packages/router/src/router.ts
@@ -1285,7 +1285,7 @@ export class Router {
     try {
       urlTree = this.urlSerializer.parse(url);
     } catch (e) {
-      urlTree = this.malformedUriErrorHandler(e, this.urlSerializer, url);
+      urlTree = this.malformedUriErrorHandler(e as URIError, this.urlSerializer, url);
     }
     return urlTree;
   }
diff --git a/packages/service-worker/cli/tsconfig.json b/packages/service-worker/cli/tsconfig.json
index 697d364ab3f..b74643fc63f 100644
--- a/packages/service-worker/cli/tsconfig.json
+++ b/packages/service-worker/cli/tsconfig.json
@@ -10,14 +10,17 @@
     "outDir": "../../../dist/all/@angular/service-worker/cli-custom",
     "noImplicitAny": true,
     "noImplicitOverride": true,
-    "useUnknownInCatchVariables": false,
     "noFallthroughCasesInSwitch": true,
     "rootDir": ".",
     "paths": {
-      "@angular/service-worker/config": ["../../../dist/packages/service-worker/config"]
+      "@angular/service-worker/config": [
+        "../../../dist/packages/service-worker/config"
+      ]
     },
     "inlineSourceMap": true,
-    "lib": ["es2020"],
+    "lib": [
+      "es2020"
+    ],
     "target": "es2020",
     "typeRoots": [],
     "types": [
@@ -28,4 +31,4 @@
     "main.ts",
     "../../../node_modules/@types/node/index.d.ts"
   ]
-}
+}
\ No newline at end of file
diff --git a/packages/service-worker/test/comm_spec.ts b/packages/service-worker/test/comm_spec.ts
index e76914957d8..9b272db4cea 100644
--- a/packages/service-worker/test/comm_spec.ts
+++ b/packages/service-worker/test/comm_spec.ts
@@ -213,7 +213,7 @@ import {MockPushManager, MockPushSubscription, MockServiceWorkerContainer, MockS
             await push.unsubscribe();
             throw new Error('`unsubscribe()` should fail');
           } catch (err) {
-            expect(err.message).toBe('Not subscribed to push notifications.');
+            expect((err as Error).message).toBe('Not subscribed to push notifications.');
           }
         });
 
@@ -234,7 +234,7 @@ import {MockPushManager, MockPushSubscription, MockServiceWorkerContainer, MockS
             await push.unsubscribe();
             throw new Error('`unsubscribe()` should fail');
           } catch (err) {
-            expect(err.message).toBe('foo');
+            expect((err as Error).message).toBe('foo');
           }
         });
 
@@ -246,7 +246,7 @@ import {MockPushManager, MockPushSubscription, MockServiceWorkerContainer, MockS
             await push.unsubscribe();
             throw new Error('`unsubscribe()` should fail');
           } catch (err) {
-            expect(err.message).toBe('Unsubscribe failed!');
+            expect((err as Error).message).toBe('Unsubscribe failed!');
           }
         });
 
diff --git a/packages/service-worker/worker/src/data.ts b/packages/service-worker/worker/src/data.ts
index 22475bc9544..6a1e60307ce 100644
--- a/packages/service-worker/worker/src/data.ts
+++ b/packages/service-worker/worker/src/data.ts
@@ -284,7 +284,8 @@ export class DataGroup {
     } catch (err) {
       // Writing lru cache table failed. This could be a result of a full storage.
       // Continue serving clients as usual.
-      this.debugHandler.log(err, `DataGroup(${this.config.name}@${this.config.version}).syncLru()`);
+      this.debugHandler.log(
+          err as Error, `DataGroup(${this.config.name}@${this.config.version}).syncLru()`);
       // TODO: Better detect/handle full storage; e.g. using
       // [navigator.storage](https://developer.mozilla.org/en-US/docs/Web/API/NavigatorStorage/storage).
     }
@@ -465,7 +466,7 @@ export class DataGroup {
         // Saving the API response failed. This could be a result of a full storage.
         // Since this data is cached lazily and temporarily, continue serving clients as usual.
         this.debugHandler.log(
-            err,
+            err as Error,
             `DataGroup(${this.config.name}@${this.config.version}).safeCacheResponse(${
                 req.url}, status: ${res.status})`);
 
diff --git a/packages/service-worker/worker/src/driver.ts b/packages/service-worker/worker/src/driver.ts
index d77c4eebdfc..7a1f3f1c6d9 100644
--- a/packages/service-worker/worker/src/driver.ts
+++ b/packages/service-worker/worker/src/driver.ts
@@ -142,7 +142,7 @@ export class Driver implements Debuggable, UpdateSource {
             await this.cleanupOldSwCaches();
           } catch (err) {
             // Nothing to do - cleanup failed. Just log it.
-            this.debugger.log(err, 'cleanupOldSwCaches @ activate: cleanup-old-sw-caches');
+            this.debugger.log(err as Error, 'cleanupOldSwCaches @ activate: cleanup-old-sw-caches');
           }
         });
       })());
@@ -409,7 +409,7 @@ export class Driver implements Debuggable, UpdateSource {
     } catch (e) {
       client.postMessage({
         ...response,
-        error: e.toString(),
+        error: (e as Error).toString(),
       });
     }
   }
@@ -479,7 +479,7 @@ export class Driver implements Debuggable, UpdateSource {
           // Handle the request. First try the AppVersion. If that doesn't work, fall back on the
           // network.
           res = await appVersion.handleFetch(event.request, event);
-        } catch (err) {
+        } catch (err: any) {
           if (err.isUnrecoverableState) {
             await this.notifyClientsAboutUnrecoverableState(appVersion, err.message);
           }
@@ -632,7 +632,7 @@ export class Driver implements Debuggable, UpdateSource {
         // it fails, then full initialization was attempted and failed.
         await this.scheduleInitialization(this.versions.get(hash)!);
       } catch (err) {
-        this.debugger.log(err, `initialize: schedule init of ${hash}`);
+        this.debugger.log(err as Error, `initialize: schedule init of ${hash}`);
         return false;
       }
     }));
@@ -781,7 +781,7 @@ export class Driver implements Debuggable, UpdateSource {
     const initialize = async () => {
       try {
         await appVersion.initializeFully();
-      } catch (err) {
+      } catch (err: any) {
         this.debugger.log(err, `initializeFully for ${appVersion.manifestHash}`);
         await this.versionFailed(appVersion, err);
       }
@@ -887,7 +887,7 @@ export class Driver implements Debuggable, UpdateSource {
 
       return true;
     } catch (err) {
-      this.debugger.log(err, `Error occurred while updating to manifest ${hash}`);
+      this.debugger.log(err as Error, `Error occurred while updating to manifest ${hash}`);
 
       this.state = DriverReadyState.EXISTING_CLIENTS_ONLY;
       this.stateMessage = `Degraded due to failed initialization: ${errorToString(err)}`;
@@ -966,7 +966,7 @@ export class Driver implements Debuggable, UpdateSource {
     } catch (err) {
       // Oh well? Not much that can be done here. These caches will be removed on the next attempt
       // or when the SW revs its format version, which happens from time to time.
-      this.debugger.log(err, 'cleanupCaches');
+      this.debugger.log(err as Error, 'cleanupCaches');
     }
   }
 
@@ -1167,7 +1167,7 @@ export class Driver implements Debuggable, UpdateSource {
     try {
       return await this.scope.fetch(req);
     } catch (err) {
-      this.debugger.log(err, `Driver.fetch(${req.url})`);
+      this.debugger.log(err as Error, `Driver.fetch(${req.url})`);
       return this.adapter.newResponse(null, {
         status: 504,
         statusText: 'Gateway Timeout',
diff --git a/packages/service-worker/worker/src/idle.ts b/packages/service-worker/worker/src/idle.ts
index 36bae8d1c06..0ba38747de0 100644
--- a/packages/service-worker/worker/src/idle.ts
+++ b/packages/service-worker/worker/src/idle.ts
@@ -73,7 +73,7 @@ export class IdleScheduler {
         try {
           await task.run();
         } catch (err) {
-          this.debug.log(err, `while running idle task ${task.desc}`);
+          this.debug.log(err as Error, `while running idle task ${task.desc}`);
         }
       }, Promise.resolve());
     }
diff --git a/packages/tsconfig-build.json b/packages/tsconfig-build.json
index 46aff24e958..094386ee286 100644
--- a/packages/tsconfig-build.json
+++ b/packages/tsconfig-build.json
@@ -11,14 +11,16 @@
     "noImplicitOverride": true,
     "strictNullChecks": true,
     "esModuleInterop": true,
-    "useUnknownInCatchVariables": false,
     "strict": true,
     "strictPropertyInitialization": true,
     "noFallthroughCasesInSwitch": true,
     "moduleResolution": "node",
     "module": "es2020",
     "target": "es2020",
-    "lib": ["es2020", "dom"],
+    "lib": [
+      "es2020",
+      "dom"
+    ],
     "skipLibCheck": true,
     // don't auto-discover @types/node, it results in a ///<reference in the .d.ts output
     "types": [],
@@ -33,4 +35,4 @@
   "bazelOptions": {
     "suppressTsconfigOverrideWarnings": true
   }
-}
+}
\ No newline at end of file
diff --git a/packages/tsconfig.json b/packages/tsconfig.json
index 592850b9961..c30d429ac28 100644
--- a/packages/tsconfig.json
+++ b/packages/tsconfig.json
@@ -17,7 +17,6 @@
     "outDir": "../dist/all/@angular",
     "noImplicitAny": true,
     "noImplicitOverride": true,
-    "useUnknownInCatchVariables": false,
     "noFallthroughCasesInSwitch": true,
     "paths": {
       "selenium-webdriver": [
@@ -68,4 +67,4 @@
     "platform-server/integrationtest",
     "router/test/aot_ngsummary_test"
   ]
-}
+}
\ No newline at end of file
diff --git a/packages/upgrade/src/common/src/downgrade_injectable.ts b/packages/upgrade/src/common/src/downgrade_injectable.ts
index af2c7a20bd6..f7b84fbb1a1 100644
--- a/packages/upgrade/src/common/src/downgrade_injectable.ts
+++ b/packages/upgrade/src/common/src/downgrade_injectable.ts
@@ -7,6 +7,7 @@
  */
 
 import {Injector} from '@angular/core';
+
 import {IInjectorService} from './angular1';
 import {$INJECTOR, INJECTOR_KEY} from './constants';
 import {getTypeName, isFunction, validateInjectionKey} from './util';
@@ -83,7 +84,7 @@ export function downgradeInjectable(token: any, downgradedModule: string = ''):
       const injector: Injector = $injector.get(injectorKey);
       return injector.get(token);
     } catch (err) {
-      throw new Error(`Error while ${attemptedAction}: ${err.message || err}`);
+      throw new Error(`Error while ${attemptedAction}: ${(err as Error).message || err}`);
     }
   };
   (factory as any)['$inject'] = [$INJECTOR];
diff --git a/packages/zone.js/lib/common/events.ts b/packages/zone.js/lib/common/events.ts
index 186773e39c4..ceed7d23dc2 100644
--- a/packages/zone.js/lib/common/events.ts
+++ b/packages/zone.js/lib/common/events.ts
@@ -123,7 +123,7 @@ export function patchEventTarget(
     let error;
     try {
       task.invoke(task, target, [event]);
-    } catch (err) {
+    } catch (err: any) {
       error = err;
     }
     const options = task.options;
diff --git a/packages/zone.js/lib/extra/bluebird.ts b/packages/zone.js/lib/extra/bluebird.ts
index e06b2ce0c6b..2319223a551 100644
--- a/packages/zone.js/lib/extra/bluebird.ts
+++ b/packages/zone.js/lib/extra/bluebird.ts
@@ -73,7 +73,7 @@ Zone.__load_patch('bluebird', (global: any, Zone: ZoneType, api: _ZonePrivate) =
           e.isHandledByZone = true;
           throw e;
         });
-      } catch (err) {
+      } catch (err: any) {
         err.isHandledByZone = false;
         api.onUnhandledError(err);
       }
diff --git a/packages/zone.js/lib/zone-spec/long-stack-trace.ts b/packages/zone.js/lib/zone-spec/long-stack-trace.ts
index a4dc1683470..50ee9826faa 100644
--- a/packages/zone.js/lib/zone-spec/long-stack-trace.ts
+++ b/packages/zone.js/lib/zone-spec/long-stack-trace.ts
@@ -30,7 +30,7 @@ function getStacktraceWithCaughtError(): Error {
   try {
     throw getStacktraceWithUncaughtError();
   } catch (err) {
-    return err;
+    return err as Error;
   }
 }
 
diff --git a/packages/zone.js/lib/zone.ts b/packages/zone.js/lib/zone.ts
index 01e13c8dce7..dc1f7b26c1e 100644
--- a/packages/zone.js/lib/zone.ts
+++ b/packages/zone.js/lib/zone.ts
@@ -1380,7 +1380,7 @@ const Zone: ZoneType = (function(global: any) {
           try {
             task.zone.runTask(task, null, null);
           } catch (error) {
-            _api.onUnhandledError(error);
+            _api.onUnhandledError(error as Error);
           }
         }
       }
diff --git a/packages/zone.js/test/browser/XMLHttpRequest.spec.ts b/packages/zone.js/test/browser/XMLHttpRequest.spec.ts
index 2c21c49f411..ee79d3f1f95 100644
--- a/packages/zone.js/test/browser/XMLHttpRequest.spec.ts
+++ b/packages/zone.js/test/browser/XMLHttpRequest.spec.ts
@@ -280,7 +280,7 @@ describe('XMLHttpRequest', function() {
       expect(req.responseType).toBe('document');
     } catch (e) {
       // Android browser: using this setter throws, this should be preserved
-      expect(e.message).toBe('INVALID_STATE_ERR: DOM Exception 11');
+      expect((e as Error).message).toBe('INVALID_STATE_ERR: DOM Exception 11');
     }
   });
 
diff --git a/packages/zone.js/test/common/zone.spec.ts b/packages/zone.js/test/common/zone.spec.ts
index 27be7617e93..e88f2db254b 100644
--- a/packages/zone.js/test/common/zone.spec.ts
+++ b/packages/zone.js/test/common/zone.spec.ts
@@ -185,8 +185,9 @@ describe('Zone', function() {
       try {
         zone.cancelTask(task);
       } catch (e) {
-        expect(e.message).toContain(
-            'macroTask \'test\': can not transition to \'canceling\', expecting state \'scheduled\' or \'running\', was \'notScheduled\'.');
+        expect((e as Error).message)
+            .toContain(
+                'macroTask \'test\': can not transition to \'canceling\', expecting state \'scheduled\' or \'running\', was \'notScheduled\'.');
       }
     });
 
diff --git a/packages/zone.js/test/test-util.ts b/packages/zone.js/test/test-util.ts
index ace7c1432d1..bd34153f660 100644
--- a/packages/zone.js/test/test-util.ts
+++ b/packages/zone.js/test/test-util.ts
@@ -77,7 +77,7 @@ let supportSetErrorStack = true;
 export function isSupportSetErrorStack() {
   try {
     throw new Error('test');
-  } catch (err) {
+  } catch (err: any) {
     try {
       err.stack = 'new stack';
       supportSetErrorStack = err.stack === 'new stack';
diff --git a/packages/zone.js/tsconfig.json b/packages/zone.js/tsconfig.json
index 0e1fdd00688..5ce77bf9fac 100644
--- a/packages/zone.js/tsconfig.json
+++ b/packages/zone.js/tsconfig.json
@@ -10,7 +10,6 @@
     "stripInternal": false,
     "strict": true,
     "noImplicitOverride": true,
-    "useUnknownInCatchVariables": false,
     "lib": [
       "es5",
       "dom",
@@ -19,7 +18,9 @@
       "es2015.symbol",
       "es2015.symbol.wellknown"
     ],
-    "typeRoots": ["node_modules/@types"],
+    "typeRoots": [
+      "node_modules/@types"
+    ],
   },
   "exclude": [
     "node_modules",
@@ -37,4 +38,4 @@
     "test/node_error_entry_point.ts",
     "test/node_tests.ts"
   ]
-}
+}
\ No newline at end of file