Angular? ???? ????????. ???? ???? ??? ????? ?? ??? ?? ?????? ?? ?? ?? ??? ????. Angular? ???? ????? ??? ??? ??? ????.

??? ??? RxJS — ? ???? Angular? ???? ???? ??? ??? ?????. RxJS ??? ?? ???? ??? ??? ??? ??? ??? ???? ?? ?????.

??? ??? ?? ??? ???? ?? ???? ???? ??? ?? RxJS ???? ???? ?? ?? ??? ??????.

inject ???? ???? ??? ??? ????? ???? ? ???, ??? ??? ?? ???? ??? ???? ???. ?? ???? ?? Rxjs ???? useFactory ??? ???? ?? ?? ??????? InjectionToken?? ??? ? ????. useFactory? ?? ??????? ?? ???? ???? ?? ?? ???? ??? ? ????.

rxjs ??? ?? ???? ?? ???? ??? ??? ? ??? ???????.

// Service
@Injectable({
  providedIn: 'root',
})
export class Multiplier {
  public transfrom(val: number) {
    return val * 2;
  }
}

?? ??? ?? RxJS ???? Multiplier ???? ???? ??? ?? 2? ????.

import { inject, InjectionToken } from '@angular/core';
import { Multiplier } from '../services/multiplier';
import { map, OperatorFunction, pipe } from 'rxjs';

export const MULTIPLIER_OPERATOR: InjectionToken<OperatorFunction<number, number>>
  = new InjectionToken('Multipler operator', {
    factory(): OperatorFunction<number, number> {
      const multipler = inject(Multiplier); // injected Multipler service
      return pipe(map((x: number) => multipler.transfrom(x)));
    },
  });

?? @Inject ?????? ???? ?? ?? ??? ??? ?? ???? ??? ? ????.

import { Component, Inject } from '@angular/core';
import { BehaviorSubject, Observable, of, OperatorFunction } from 'rxjs';
import { MULTIPLIER_OPERATOR } from './rxjs-operators/custom';
import { CommonModule } from '@angular/common';

export class App {
  private _count = 1;
  public base = new BehaviorSubject(this._count);
  public val = new Observable();

  constructor(
    @Inject(MULTIPLIER_OPERATOR) // injected custom operator
    private multiplier: OperatorFunction<number, number>) {
      this.val = this.base.pipe(this.multiplier); // used rxjs operator
  }

  .....
}

??? ???? ???? ??? ?? ???? ???? ???? ??? ? ??? ?? ??? ???? ?? ?? ??? ????. ??? ?? ?? ??? ??? InjectionToken ?? ??? ?????. RxJS? ???? ?????? ??? ???? ???? ?? ?? ???? ???? ??? ????.

???? ?? ?? ??? ? ? ????.

??? ??...?

? ??? ?? ??? ?? — ??? ?? Rxjs ??? ??? ??? ??? ?? ?????. ??? ??? PHP ??? ????? ?? ?? ??? ?????!