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Andrew Scott
0abb67af59
The current Router APIs require guards/resolvers to be present in the DI tree. This is because we want to treat all guards/resolvers equally and some may require dependencies. This requirement results in quite a lot of boilerplate for guards. Here are two examples:
```
const MY_GUARD = new InjectionToken<any>('my_guard');
…
providers: {provide: MY_GUARD, useValue: () => window.someGlobalState}
…
const route = {path: 'somePath', canActivate: [MY_GUARD]}
```
```
@Injectable({providedIn: 'root'})
export class MyGuardWithDependency {
constructor(private myDep: MyDependency) {}
canActivate() {
return myDep.canActivate();
}
}
…
const route = {path: 'somePath', canActivate: [MyGuardWithDependency]}
```
Notice that even when we want to write a simple guard that has no dependencies as in the first example, we still have to write either an InjectionToken or an Injectable class.
With this commit router guards and resolvers can be plain old functions.
For example:
```
const route = {path: 'somePath', component: EditCmp, canDeactivate: [(component: EditCmp) => !component.hasUnsavedChanges]}
```
Additionally, these functions can still use Angular DI with `inject` from `@angular/core`.
```
const route = {path: 'somePath', canActivate: [() => inject(MyDependency).canActivate()]}
```
PR Close #46684
Angular Router
Managing state transitions is one of the hardest parts of building applications. This is especially true on the web, where you also need to ensure that the state is reflected in the URL. In addition, we often want to split applications into multiple bundles and load them on demand. Doing this transparently isn’t trivial.
The Angular router is designed to solve these problems. Using the router, you can declaratively specify application state, manage state transitions while taking care of the URL, and load components on demand.
Guide
Read the dev guide here.