Angular2에서 구독을 취소하는 방법

Angular2에서 구독을 취소하는 방법

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Angular2에서 구독을 어떻게 취소합니까? RxJS에 처리 방법이있는 것 같지만 액세스 방법을 알 수 없습니다. 그래서 다음과 같이 EventEmitter에 대한 액세스 권한이 있고 구독하는 코드가 있습니다.

var mySubscription = someEventEmitter.subscribe(
    (val) => {
        console.log('Received:', val);
    },
    (err) => {
        console.log('Received error:', err);
    },
    () => {
        console.log('Completed');
    }
);

어떻게 사용할 수있는 mySubscription구독을 취소하려면?

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구독을 취소 하시겠습니까?

mySubscription.unsubscribe();

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나도 2 센트를 넣었다고 생각했다. 이 패턴을 사용합니다.

import { Component, OnInit, OnDestroy } from '@angular/core';
import { Subscription } from 'rxjs/Subscription';

@Component({
    selector: 'my-component',
    templateUrl: 'my.component.html'
})
export class MyComponent implements OnInit, OnDestroy {

    private subscriptions: Array<Subscription> = [];

    public ngOnInit(): void {
        this.subscriptions.push(this.someService.change.subscribe(() => {
            [...]
        }));

        this.subscriptions.push(this.someOtherService.select.subscribe(() => {
            [...]
        }));
    }

    public ngOnDestroy(): void {
        this.subscriptions.forEach((subscription: Subscription) => {
            subscription.unsubscribe();
        });
    }
}

편집하다

요 전에 문서를 읽고 더 권장되는 패턴을 찾았습니다.

ReactiveX / RxJS / 구독

장점 :

내부적으로 새 구독을 관리하고 몇 가지 깔끔한 검사를 추가합니다. 기능 에서이 방법을 선호합니다 :).

단점 :

코드 흐름이 무엇인지, 구독이 어떻게 영향을 받는지는 100 % 명확하지 않습니다. 또한 (코드를 보는 것만으로도) 폐쇄 된 구독을 처리하는 방법과 구독 취소가 호출되면 모든 구독이 닫히는 지 명확하지 않습니다.

import { Component, OnInit, OnDestroy } from '@angular/core';
import { Subscription } from 'rxjs/Subscription';

@Component({
    selector: 'my-component',
    templateUrl: 'my.component.html'
})
export class MyComponent implements OnInit, OnDestroy {

    private subscription: Subscription = new Subscription();

    public ngOnInit(): void {
        this.subscription.add(this.someService.change.subscribe(() => {
            [...]
        }));

        this.subscription.add(this.someOtherService.select.subscribe(() => {
            [...]
        }));
    }

    public ngOnDestroy(): void {
        /*
         * magic kicks in here: All subscriptions which were added
         * with "subscription.add" are canceled too!
         */
        this.subscription.unsubscribe();
    }
}

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편집 : 이것은 angular2가 사용하는 RxJS 5에는 적용되지 않습니다.

Disposable 에서 dispose 메서드를 찾고 있다고 생각했을 것 입니다.

subscribe 메서드는 Disposable ( link )을 반환합니다.

문서에서 더 명시 적으로 찾을 수없는 것 같지만 작동합니다 ( jsbin ).

var observable = Rx.Observable.interval(100);

var subscription = observable.subscribe(function(value) {
   console.log(value);
});

setTimeout(function() {
  subscription.dispose();           
}, 1000)

이상하게도 구독 취소가 효과가있는 것 같습니다.

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Far too many different explanations of unsubscribe on Observables for ng2, took me ages to find the right answer. Below is a working example (I was trying to throttle mousemove).

import {Injectable, OnDestroy} from "@angular/core";
import {Subscription} from "rxjs";

@Injectable()
export class MyClass implements OnDestroy {
  
  mouseSubscription: Subscription; //Set a variable for your subscription
  
  myFunct() {
    // I'm trying to throttle mousemove
    const eachSecond$ = Observable.timer(0, 1000);
    const mouseMove$ = Observable.fromEvent<MouseEvent>(document, 'mousemove');
    const mouseMoveEachSecond$ = mouseMove$.sample(eachSecond$);
    
    this.mouseSubscription = mouseMoveEachSecond$.subscribe(() => this.doSomethingElse());
  }

  doSomethingElse() {
    console.log("mouse moved");
  }
  
  stopNow() {
    this.mouseSubscription.unsubscribe();
  }
  
  ngOnDestroy() {
    this.mouseSubscription.unsubscribe();
  }
  
}

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ngOnDestroy(){
   mySubscription.unsubscribe();
}

Prefer unsubscribing rxjs unsubscribe's while destroying the component i.e., removing from DOM for avoiding unecessary memory leaks

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I prefer personally to use a Subject to close all subscriptions a component might have at the destroy life cycle step which can be achieved this way :

import { Component} from '@angular/core';
import { Subject } from "rxjs/Rx";

@Component({
  selector:    'some-class-app',
  templateUrl: './someClass.component.html',
  providers:   []
})

export class SomeClass {  

  private ngUnsubscribe: Subject<void> = new Subject<void>(); //This subject will tell every subscriptions to stop when the component is destroyed.

  //**********
  constructor() {}

  ngOnInit() {

    this.http.post( "SomeUrl.com", {}, null ).map( response => {

      console.log( "Yay." );

    }).takeUntil( this.ngUnsubscribe ).subscribe(); //This is where you tell the subscription to stop whenever the component will be destroyed.
  }

  ngOnDestroy() {

    //This is where we close any active subscription.
    this.ngUnsubscribe.next();
    this.ngUnsubscribe.complete();
  }
}

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Use

if(mySubscription){
  mySubscription.unsubscribe();
}

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The recommended approach is to use RxJS operators such as the takeUntil operator. Below is the code snippet showing how to use it :-

import { Component, OnInit, OnDestroy } from '@angular/core';
import { interval, Subject } from 'rxjs';
import { takeUntil } from 'rxjs/operators';

@Component({
    selector: 'app-root',
    templateUrl: './app.component.html'
})
export class AppComponent implements OnInit, OnDestroy {
    private ngUnsubscribe = new Subject();

    constructor() { }

    ngOnInit() {
        var observable1 = interval(1000);
        var observable2 = interval(2000);

        observable1.pipe(takeUntil(this.ngUnsubscribe)).subscribe(x => console.log('observable1: ' + x));
        observable2.pipe(takeUntil(this.ngUnsubscribe)).subscribe(x => console.log('observable2: ' + x));
    }

    ngOnDestroy() {
        this.ngUnsubscribe.next();
        this.ngUnsubscribe.complete();
    }
}

You can find a detailed explanation of the topic here

참고URL : https://stackoverflow.com/questions/34442693/how-to-cancel-a-subscription-in-angular2