How to disable click event binding in Angular2 after it has been clicked once

Question

How to disable click event binding in Angular2 after it has been clicked once

Within my application, there is a button that has a click event attached to it:

<button class="btn btn-default" (click)="doSomething()">

I am wondering if there is a way to remove the (click) event from the button within the doSomething method so that users cannot trigger the functionality anymore.

I attempted to set a disabled property on the button, but it did not change Angular2's behavior.

I also tried using (click)="doSomething($event)" and then

doSomething($event) {
  // The logic of my method is implemented here
  ...
  ...
  console.log('Method Logic');

  // Attempting to override the click event
  let target = event.target || event.srcElement || event.currentTarget;
  this.renderer.listen(target, 'click', (event) => {
      console.log('Click block');
    });
}

However, this approach does not successfully replace the click event. As a result, both the original logic and the "click block" console log are triggered upon clicking.

javascript angular typescript

Answer 1

Answer №1

Approach 1:

An effective way to handle this scenario is by utilizing a boolean variable. By toggling the boolean value upon function call, the user can trigger the function again on click without any actual changes.

bool: boolean = true;

doSomething($event) {
  if (this.bool) {
    // Implementing method logic here
    ...
    ...
    console.log('Method Logic');
    this.bool = false;
  }
}

Approach 2:

Another approach is to integrate a condition within the HTML component. If the specified variable (in this case 'bool') evaluates to true, the function will execute once. Subsequently, setting 'bool' to false ensures that the 'click' function does not perform any actions thereafter.

bool: boolean = true;

doSomething($event) {
  // Implementing method logic here
  ...
  ...
  console.log('Method Logic');
  this.bool = false;
}

(click)="bool ? doSomething($event) : null"

Answer 2

Approach 1:

An effective way to handle this scenario is by utilizing a boolean variable. By toggling the boolean value upon function call, the user can trigger the function again on click without any actual changes.

bool: boolean = true;

doSomething($event) {
  if (this.bool) {
    // Implementing method logic here
    ...
    ...
    console.log('Method Logic');
    this.bool = false;
  }
}

Approach 2:

Another approach is to integrate a condition within the HTML component. If the specified variable (in this case 'bool') evaluates to true, the function will execute once. Subsequently, setting 'bool' to false ensures that the 'click' function does not perform any actions thereafter.

bool: boolean = true;

doSomething($event) {
  // Implementing method logic here
  ...
  ...
  console.log('Method Logic');
  this.bool = false;
}

(click)="bool ? doSomething($event) : null"

Answer 3

Answer №2

One drawback of simply adding a guard variable to control execution is that the event listener remains active and will still trigger Angular's change detection upon clicking, even though it serves no purpose.

To effectively remove the event listener, you must include it through the component's Renderer. This will provide a function that can be called to eliminate the event listener:

import {Component, AfterViewInit, Renderer, ViewChild, ElementRef} from '@angular/core';

@Component({
  template: `<button #button>...</button>`
})
export class SampleComponent implements AfterViewInit {

  @ViewChild('button') button: ElementRef;
  private cancelClick: Function;

  constructor(private renderer: Renderer) {}

  ngAfterViewInit() {
    this.cancelClick = this.renderer.listen(this.button.nativeElement, 'click',
      ($event: any) => this.handleClick($event));
  }

  handleClick($event: any) {
    this.cancelClick();
    // ...
  }
}

If your aim is to remove the event listener after it has been triggered once, this functionality can be integrated as an Angular event system plugin. I have included it in my custom ng2-events utility library [source], enabling you to use the following syntax:

<button (once.click)="handleClick($event)">...</button>

Answer 4

One drawback of simply adding a guard variable to control execution is that the event listener remains active and will still trigger Angular's change detection upon clicking, even though it serves no purpose.

To effectively remove the event listener, you must include it through the component's Renderer. This will provide a function that can be called to eliminate the event listener:

import {Component, AfterViewInit, Renderer, ViewChild, ElementRef} from '@angular/core';

@Component({
  template: `<button #button>...</button>`
})
export class SampleComponent implements AfterViewInit {

  @ViewChild('button') button: ElementRef;
  private cancelClick: Function;

  constructor(private renderer: Renderer) {}

  ngAfterViewInit() {
    this.cancelClick = this.renderer.listen(this.button.nativeElement, 'click',
      ($event: any) => this.handleClick($event));
  }

  handleClick($event: any) {
    this.cancelClick();
    // ...
  }
}

If your aim is to remove the event listener after it has been triggered once, this functionality can be integrated as an Angular event system plugin. I have included it in my custom ng2-events utility library [source], enabling you to use the following syntax:

<button (once.click)="handleClick($event)">...</button>

Answer 5

Answer №3

Dealing with Observables and Subjects to manage events can be a powerful tool:

<button (click)="handleClickEvents($event)">

class EventManager {
  clickEvents$ = new Subject<MouseEvent>();
  firstClick$ = this.clickEvents.take(1); // Observable representing the first click event
}

Answer 6

Dealing with Observables and Subjects to manage events can be a powerful tool:

<button (click)="handleClickEvents($event)">

class EventManager {
  clickEvents$ = new Subject<MouseEvent>();
  firstClick$ = this.clickEvents.take(1); // Observable representing the first click event
}

How to disable click event binding in Angular2 after it has been clicked once

Answer №1

Answer №2

Answer №3

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