How to use standalone pipe in NGRX effect in moduleless approach

Question

I am migrating my app to Angular 18 and converting some parts to standalone. One of the first things I migrated was NGRX store.

I've had StoreModule, which imported FeatureModules. Two of them use SomePipe.

Now I have an index.ts which uses makeEnvironmentProviders to gather all providers from Feature module.

const buildStore = () => makeEnvironmentProviders([
  provideFeature1(),
  provideFeature2(),
...
  makeEnvironmentProviders([
    provideStoreState({ name: 'feature-10', reducer }),
    provideEffects(effects),
  ])
]);

As mentioned some effects (which are services) depend on a pipe (which is now standalone). When I had modules, I just provided/imported the pipe and it worked.

If I now put the pipe in one of my makeEnvironmentProviders it will end up in app.config and thus be available everywhere. No scoping.

Is there a way to achieve such "scoping" using this approach?? How should it be done?

Using Pipe in an Effect might be discouraged, but for now it has to stay that way in our project.

Answer 1

To achieve proper scoping while using your Pipe logic in both the Pipe and Effect, I suggest abstracting the Pipe's logic into a separate function. This approach avoids the "hacky" way of globally providing the Pipe and makes your code cleaner and more maintainable.

Step-by-Step Solution

1. Extract Pipe Logic into a Function: Move the logic within your Pipe to a standalone function. If the logic requires injected services, use Angular's inject function.

// pipe-logic.ts
import { inject } from '@angular/core';
import { SomeService } from './some.service';

export function injectPipeLogicFunc() {
  const someService = inject(SomeService);

  // Write your logic here
  return (value: any, ...args: any[]) => {
    const result = someService.someMethod(value, ...args);
    return result;
  };
}

2. Use the Function in Your Pipe: Modify your Pipe to utilize this extracted logic.

// your-pipe.pipe.ts
import { Pipe, PipeTransform } from '@angular/core';
import { injectPipeLogicFunc } from './pipe-logic';

@Pipe({ name: 'yourPipe' })
export class YourPipe implements PipeTransform {
  private pipeLogic = injectPipeLogicFunc();

  transform(value: any, ...args: any[]): any {
    return this.pipeLogic(value, ...args);
  }
}

3. Use the Function in Your Effect: Similarly, use the function within your Effect to maintain consistency.

// some-effect.effect.ts
import { Injectable } from '@angular/core';
import { Actions, createEffect, ofType } from '@ngrx/effects';
import { map } from 'rxjs/operators';
import { someAction } from './actions';
import { injectPipeLogicFunc } from './pipe-logic';

@Injectable()
export class SomeEffect {
  private pipeLogic = injectPipeLogicFunc();

  constructor(private actions$: Actions) {}

  someEffect = createEffect(() =>
    this.actions$.pipe(
      ofType(someAction),
      map(({ payload }) => {
        return this.pipeLogic(payload);
      }),
    )
  );
}

Benefits of this Approach:

• Separation of Concerns: The logic is decoupled from the Pipe, making each unit testable independently.
• Reuse: You can reuse the function across different parts of your application.
• Scoped Dependence: You avoid globally providing the Pipe, thus maintaining scoped dependency.

Using this method, you can ensure that your logic stays organized and maintainable, fitting well within Angular's dependency injection system.

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