Wednesday, 1 December 2021

How to get a dynamically generated element in Angular without querySelector?

I am currently creating my own toastr service as seen in the GIF below


enter image description here


The issue Whenever I click the CTA button I add a toast element to an array of toasts which the component is subscribed to and utilizes to update the DOM.

The toasts are generated like this:

export class ToastComponent implements OnInit {
  constructor(private toast: ToastService, protected elementRef: ElementRef) {}

  toasts = this.toast.Toasts;

  <div
    class="toast-wrapper wobble-animation"
    *ngFor="let t of toasts.value"
    (click)="DestroyToast(t, $event)"

What I want I want to add an eventlistener to the toast whenever 'animationend' to destroy the HTML element. I already do this by when clicking with this line of code:

       DestroyToast(element, event): void {
        event.target.classList.remove('wobble-animation');
        event.target.classList.add('slide-out-animation');
        event.target.addEventListener('animationend', () => {
          this.toasts.value.splice(this.toasts.value.indexOf(element), 1);
        });
      }

My initial thought was to subscribe to the array and use that as an eventlistener for when something is pushed. I would then use a function to fetch the latest toast and add another eventlistener, the 'animationend' one.

I tried the method like this:

  ngOnInit(): void {
      this.toast.Toasts.subscribe((args) => {
      this.UpdateToasts();
     });
  }
  UpdateToasts() {
    let toastElements = document.querySelectorAll('.toast');
    console.log(toastElements);
  }

But unfortunately it is too slow and always returns null on the first event.

enter image description here


I think that I have read that using querySelector in angular is generally bad practice. So the question is:

How to get a dynamically generated element in Angular without querySelector?


FULL CODE

Toast.Component.ts

import { ToastService } from './../../services/toast.service';
import { toast } from './toast.model';
import { Component, OnInit, ElementRef } from '@angular/core';
import { Observable } from 'rxjs';

@Component({
  selector: 'app-toast',
  templateUrl: './toast.component.html',
  styleUrls: ['./toast.component.scss'],
})
export class ToastComponent implements OnInit {
  constructor(private toast: ToastService, protected elementRef: ElementRef) {}

  toasts = this.toast.Toasts;
  ngOnInit(): void {
    this.toast.Toasts.subscribe((args) => {
      this.UpdateToasts();
    });
  }
  ngOnDestroy() {
    this.toasts.unsubscribe();
  }
  DestroyToast(element, event): void {
    event.target.classList.remove('wobble-animation');
    event.target.classList.add('slide-out-animation');
    event.target.addEventListener('animationend', () => {
      this.toasts.value.splice(this.toasts.value.indexOf(element), 1);
    });
  }
  UpdateToasts() {
    let toastElements = document.querySelectorAll('.toast');
    console.log(toastElements);
  }
}

Toast.Component.html

<div class="toast-container">
  <div
    class="toast-wrapper wobble-animation"
    *ngFor="let t of toasts.value"
    (click)="DestroyToast(t, $event)"
  >
    <div
      class="toast default"
      [ngClass]="{ 'slide-out-animation': t.TimeLeft < 1 }"
    >
      <div class="notification-count" *ngIf="t.Count > 1">
        
      </div>
      <div class="content-container">
        <p class="title">
          
        </p>
        <p class="content"></p>
      </div>
      <span class="progress">
        <span
          class="real-progress"
          [ngStyle]="{ 'width.%': t.PercentageCompleted }"
        ></span>
      </span>
    </div>
  </div>
</div>

Toast.Service.ts

import { Injectable } from '@angular/core';
import { BehaviorSubject } from 'rxjs/internal/BehaviorSubject';
import { toast } from '../components/toast/toast.model';

@Injectable({
  providedIn: 'root',
})
export class ToastService {
  public Toasts = new BehaviorSubject<Array<object>>([]);

  constructor() {}

  Toast(Title: string, Message?: string, Style?: string, Timer?: number) {
    const toastModel = new toast({
      Title: Title,
      Content: Message,
      Timer: Timer,
      Style: Style,
      TimeLeft: Timer,
      Count: 1,
      PercentageCompleted: 100,
    });
    this.AddToast(toastModel);
  }

  private AddToast(toast: toast) {
    const currentArr = this.Toasts.value;
    const updatedToast = [...currentArr, toast];
    let timer = setInterval(function () {
      toast.PercentageCompleted = toast.TimeLeft / (toast.Timer / 100);
      toast.TimeLeft = toast.TimeLeft - 10;
      if (toast.TimeLeft <= 0 || !toast.TimeLeft) {
        clearInterval(timer);
      }
    }, 10);
    this.Toasts.next(updatedToast);
  }
}

Link to website with live code ModernnaMedia



from How to get a dynamically generated element in Angular without querySelector?

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