refactor(migrations): add API to remap generated import names (#48974)

Internally we'll need to remap some imports to generate better import statements. These changes add an API that we can use to do the remapping.

PR Close #48974

packages/core/schematics/ng-generate/standalone-migration/prune-modules.ts

@@ -12,7 +12,7 @@ import ts from 'typescript';
 import {getAngularDecorators, NgDecorator} from '../../utils/ng_decorators';
 import {closestNode} from '../../utils/typescript/nodes';
 
-import {ChangeTracker, createLanguageService, findClassDeclaration, findLiteralProperty, getNodeLookup, offsetsToNodes, UniqueItemTracker} from './util';
+import {ChangeTracker, createLanguageService, findClassDeclaration, findLiteralProperty, getNodeLookup, ImportRemapper, offsetsToNodes, UniqueItemTracker} from './util';
 
 /** Mapping between a file name and spans for node references inside of it. */
 type ReferencesByFile = Map<string, [start: number, end: number][]>;
@@ -28,9 +28,9 @@ interface RemovalLocations {
 
 export function pruneNgModules(
     program: NgtscProgram, host: ts.CompilerHost, basePath: string, rootFileNames: string[],
-    sourceFiles: ts.SourceFile[], printer: ts.Printer) {
+    sourceFiles: ts.SourceFile[], printer: ts.Printer, importRemapper?: ImportRemapper) {
   const filesToRemove = new Set<ts.SourceFile>();
-  const tracker = new ChangeTracker(printer);
+  const tracker = new ChangeTracker(printer, importRemapper);
   const typeChecker = program.getTsProgram().getTypeChecker();
   const languageService = createLanguageService(program, host, rootFileNames, basePath);
   const removalLocations: RemovalLocations = {

packages/core/schematics/ng-generate/standalone-migration/standalone-bootstrap.ts

@@ -16,7 +16,7 @@ import {getAngularDecorators} from '../../utils/ng_decorators';
 import {closestNode} from '../../utils/typescript/nodes';
 
 import {convertNgModuleDeclarationToStandalone} from './to-standalone';
-import {ChangeTracker, createLanguageService, findClassDeclaration, findLiteralProperty, getNodeLookup, getRelativeImportPath, NamedClassDeclaration, NodeLookup, offsetsToNodes, UniqueItemTracker} from './util';
+import {ChangeTracker, createLanguageService, findClassDeclaration, findLiteralProperty, getNodeLookup, getRelativeImportPath, ImportRemapper, NamedClassDeclaration, NodeLookup, offsetsToNodes, UniqueItemTracker} from './util';
 
 /** Information extracted from a `bootstrapModule` call necessary to migrate it. */
 interface BootstrapCallAnalysis {
@@ -32,8 +32,8 @@ interface BootstrapCallAnalysis {
 
 export function toStandaloneBootstrap(
     program: NgtscProgram, host: ts.CompilerHost, basePath: string, rootFileNames: string[],
-    sourceFiles: ts.SourceFile[], printer: ts.Printer) {
-  const tracker = new ChangeTracker(printer);
+    sourceFiles: ts.SourceFile[], printer: ts.Printer, importRemapper?: ImportRemapper) {
+  const tracker = new ChangeTracker(printer, importRemapper);
   const typeChecker = program.getTsProgram().getTypeChecker();
   const templateTypeChecker = program.compiler.getTemplateTypeChecker();
   const languageService = createLanguageService(program, host, rootFileNames, basePath);

packages/core/schematics/ng-generate/standalone-migration/to-standalone.ts

@@ -15,7 +15,7 @@ import {getImportSpecifier} from '../../utils/typescript/imports';
 import {closestNode} from '../../utils/typescript/nodes';
 import {isReferenceToImport} from '../../utils/typescript/symbol';
 
-import {ChangesByFile, ChangeTracker, findClassDeclaration, findLiteralProperty, NamedClassDeclaration} from './util';
+import {ChangesByFile, ChangeTracker, findClassDeclaration, findLiteralProperty, ImportRemapper, NamedClassDeclaration} from './util';
 
 /**
  * Converts all declarations in the specified files to standalone.
@@ -24,13 +24,14 @@ import {ChangesByFile, ChangeTracker, findClassDeclaration, findLiteralProperty,
  * @param printer
  */
 export function toStandalone(
-    sourceFiles: ts.SourceFile[], program: NgtscProgram, printer: ts.Printer): ChangesByFile {
+    sourceFiles: ts.SourceFile[], program: NgtscProgram, printer: ts.Printer,
+    importRemapper?: ImportRemapper): ChangesByFile {
   const templateTypeChecker = program.compiler.getTemplateTypeChecker();
   const typeChecker = program.getTsProgram().getTypeChecker();
   const modulesToMigrate: ts.ClassDeclaration[] = [];
   const testObjectsToMigrate: ts.ObjectLiteralExpression[] = [];
   const declarations: Reference<ts.ClassDeclaration>[] = [];
-  const tracker = new ChangeTracker(printer);
+  const tracker = new ChangeTracker(printer, importRemapper);
 
   for (const sourceFile of sourceFiles) {
     const {modules, testObjects} = findModulesToMigrate(sourceFile, typeChecker);

packages/core/schematics/ng-generate/standalone-migration/util.ts

@@ -21,6 +21,9 @@ export type NodeLookup = Map<number, ts.Node[]>;
 /** Utility to type a class declaration with a name. */
 export type NamedClassDeclaration = ts.ClassDeclaration&{name: ts.Identifier};
 
+/** Function that can be used to remap a generated import. */
+export type ImportRemapper = (moduleName: string) => string;
+
 /** Change that needs to be applied to a file. */
 interface PendingChange {
   /** Index at which to start changing the file. */
@@ -45,7 +48,7 @@ export class ChangeTracker {
       }),
       this._printer);
 
-  constructor(private _printer: ts.Printer) {}
+  constructor(private _printer: ts.Printer, private _importRemapper?: ImportRemapper) {}
 
   /**
    * Tracks the insertion of some text.
@@ -104,7 +107,9 @@ export class ChangeTracker {
   addImport(
       sourceFile: ts.SourceFile, symbolName: string, moduleName: string,
       alias: string|null = null): ts.Expression {
-    return this._importManager.addImportToSourceFile(sourceFile, symbolName, moduleName, alias);
+    return this._importManager.addImportToSourceFile(
+        sourceFile, symbolName,
+        this._importRemapper ? this._importRemapper(moduleName) : moduleName, alias);
   }
 
   /**