"Discovering the root cause of Angular memory leaks and resolving them effectively is crucial for

Question

"Discovering the root cause of Angular memory leaks and resolving them effectively is crucial for

I am facing an issue with a code that appears to be leaking, and I am seeking advice on how to identify the cause or properly unsubscribe. Even after adding an array containing all object subscriptions, the memory leakage persists.

import { Component, OnInit } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { of } from 'rxjs';
import { delay, tap, mergeMap, repeat } from 'rxjs/operators';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent implements OnInit {

  postId;
  
  callOmni = () => of(this.pollOmni()).pipe();
  display = response => {};
  poll = of({}).pipe(
  mergeMap(_ => this.callOmni()),
  tap(this.display),
  delay(10),
  repeat()
);

  constructor(private http: HttpClient) { } 
  pollOmni() {      
    // Simple POST request with a JSON body and response type <any>
    this.http.post<any>('http://127.0.0.1:8084/api', { call: 'getinfo' }).subscribe(
      data => {
        this.postId = data;
        console.log(this.postId);
        }),
        error => {
          console.log('oops', error)
        }
     
   
  }

  ngOnInit() {      
    // Simple POST request with a JSON body and response type <any>
   
    this.poll.subscribe();
  }

}

angular typescript httpclient

Answer 1

Answer №1

Your code appears to have a subscription issue within the pollOmni() method, leading to multiple active subscriptions that can cause memory leaks if not unsubscribed properly.

To resolve this issue, ensure you unsubscribe from the subscription when no longer needed. One approach is to store the subscription in a variable and unsubscribe as necessary.

Below is an updated version of your code with the necessary modifications implemented:

import { Component, OnInit, OnDestroy } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { of, Subject } from 'rxjs';
import { delay, tap, mergeMap, repeat, takeUntil } from 'rxjs/operators';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent implements OnInit, OnDestroy {
  postId;
  private ngUnsubscribe = new Subject<void>(); // Subject for unsubscribing

  constructor(private http: HttpClient) { }

  callOmni = () => of(this.pollOmni()).pipe();

  display = response => {
    // Display logic here
  };

  poll = of({}).pipe(
    mergeMap(_ => this.callOmni()),
    tap(this.display),
    delay(10),
    repeat(),
    takeUntil(this.ngUnsubscribe) // Unsubscribe when ngUnsubscribe emits
  );

  pollOmni() {
    return this.http.post<any>('http://127.0.0.1:8084/api', { call: 'getinfo' });
  }

  ngOnInit() {
    this.poll.subscribe();
  }

  ngOnDestroy() {
    this.ngUnsubscribe.next(); // Emit value to unsubscribe from ongoing subscriptions
    this.ngUnsubscribe.complete(); // Complete the subject
  }
}

Answer 2

Your code appears to have a subscription issue within the pollOmni() method, leading to multiple active subscriptions that can cause memory leaks if not unsubscribed properly.

To resolve this issue, ensure you unsubscribe from the subscription when no longer needed. One approach is to store the subscription in a variable and unsubscribe as necessary.

Below is an updated version of your code with the necessary modifications implemented:

import { Component, OnInit, OnDestroy } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { of, Subject } from 'rxjs';
import { delay, tap, mergeMap, repeat, takeUntil } from 'rxjs/operators';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent implements OnInit, OnDestroy {
  postId;
  private ngUnsubscribe = new Subject<void>(); // Subject for unsubscribing

  constructor(private http: HttpClient) { }

  callOmni = () => of(this.pollOmni()).pipe();

  display = response => {
    // Display logic here
  };

  poll = of({}).pipe(
    mergeMap(_ => this.callOmni()),
    tap(this.display),
    delay(10),
    repeat(),
    takeUntil(this.ngUnsubscribe) // Unsubscribe when ngUnsubscribe emits
  );

  pollOmni() {
    return this.http.post<any>('http://127.0.0.1:8084/api', { call: 'getinfo' });
  }

  ngOnInit() {
    this.poll.subscribe();
  }

  ngOnDestroy() {
    this.ngUnsubscribe.next(); // Emit value to unsubscribe from ongoing subscriptions
    this.ngUnsubscribe.complete(); // Complete the subject
  }
}

Answer 3

Answer №2

Here is an example:

class ExampleComponent implements OnChanges, AfterViewInit {
  ...

  ngAfterViewInit(): void {
    this.subscription.unsubscribe();
  }
}

Answer 4

Here is an example:

class ExampleComponent implements OnChanges, AfterViewInit {
  ...

  ngAfterViewInit(): void {
    this.subscription.unsubscribe();
  }
}

Answer 5

Answer №3

Ensure your code includes the OnDestroy Life cycle hook in Angular and properly unsubscribe within the ngOnDestroy method as shown below:

import { Component, OnInit, OnDestroy } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { of } from 'rxjs';
import { delay, tap, mergeMap, repeat } from 'rxjs/operators';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent implements OnInit, OnDestroy {

  postId;
  private unsubscribe = new Subject<void>();
  callOmni = () => of(this.pollOmni()).pipe();
  display = response => {};
  poll = of({}).pipe(
    mergeMap(_ => this.callOmni()),
    tap(this.display),
    delay(10),
    repeat(),
    takeUntil(this.unsubscribe)
);

constructor(private http: HttpClient) { } 
pollOmni() {      
    
    this.http.post<any>('http://127.0.0.1:8084/api', { call: 'getinfo' }).subscribe(
      data => {
        this.postId = data;
        console.log(this.postId);
        }),
        error => {
          console.log('oops', error)
        }
     
   
  }

  ngOnInit() {      
    this.poll.subscribe();
  }

ngOnDestroy(): void {
    this.unsubscribe.next(); 
   this.unsubscribe.complete();
  }
}

If the above solution does not meet your requirements, consider utilizing the template mechanism in Angular using the Angular Async Pipe. Please see the sample implementation below demonstrating the usage of pipes in Angular.

@Component({
      selector: 'app-stock',
      template: `
        <div *ngIf="stocks$ | async as stocks">
          <ul>
            <li *ngFor="let stock of stocks">
              {{ stock.symbol }}
            </li>
          </ul>
        </div>
      `,
      styleUrls: ['./stock.component.scss'],
    })
    export class StockComponent implements OnInit {
      stocks$: Observable<Stock[]> = this.stockService.getStocks();
    
      constructor(private stockService: StockService) {}
    
      ngOnInit(): void {}
    }

Answer 6

Ensure your code includes the OnDestroy Life cycle hook in Angular and properly unsubscribe within the ngOnDestroy method as shown below:

import { Component, OnInit, OnDestroy } from '@angular/core';
import { HttpClient } from '@angular/common/http';
import { of } from 'rxjs';
import { delay, tap, mergeMap, repeat } from 'rxjs/operators';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent implements OnInit, OnDestroy {

  postId;
  private unsubscribe = new Subject<void>();
  callOmni = () => of(this.pollOmni()).pipe();
  display = response => {};
  poll = of({}).pipe(
    mergeMap(_ => this.callOmni()),
    tap(this.display),
    delay(10),
    repeat(),
    takeUntil(this.unsubscribe)
);

constructor(private http: HttpClient) { } 
pollOmni() {      
    
    this.http.post<any>('http://127.0.0.1:8084/api', { call: 'getinfo' }).subscribe(
      data => {
        this.postId = data;
        console.log(this.postId);
        }),
        error => {
          console.log('oops', error)
        }
     
   
  }

  ngOnInit() {      
    this.poll.subscribe();
  }

ngOnDestroy(): void {
    this.unsubscribe.next(); 
   this.unsubscribe.complete();
  }
}

If the above solution does not meet your requirements, consider utilizing the template mechanism in Angular using the Angular Async Pipe. Please see the sample implementation below demonstrating the usage of pipes in Angular.

@Component({
      selector: 'app-stock',
      template: `
        <div *ngIf="stocks$ | async as stocks">
          <ul>
            <li *ngFor="let stock of stocks">
              {{ stock.symbol }}
            </li>
          </ul>
        </div>
      `,
      styleUrls: ['./stock.component.scss'],
    })
    export class StockComponent implements OnInit {
      stocks$: Observable<Stock[]> = this.stockService.getStocks();
    
      constructor(private stockService: StockService) {}
    
      ngOnInit(): void {}
    }

"Discovering the root cause of Angular memory leaks and resolving them effectively is crucial for

Answer №1

Answer №2

Answer №3

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