How can I listen for keypress event on the whole page?

Question

I'm looking for a way to bind a function to my whole page (when a user presses a key, I want it to trigger a function in my component.ts)

It was easy in AngularJS with a ng-keypress but it does not work with (keypress)="handleInput($event)".

I tried it with a div wrapper on the whole page but it doesn't seem to work. it only works when the focus is on it.

<div (keypress)="handleInput($event)" tabindex="1">

Answer 1

I would use @HostListener decorator within your component:

import { HostListener } from '@angular/core';

@Component({
  ...
})
export class AppComponent {

  @HostListener('document:keypress', ['$event'])
  handleKeyboardEvent(event: KeyboardEvent) { 
    this.key = event.key;
  }
}

There are also other options like:

host property within @Component decorator

Angular recommends using @HostListener decorator over host property https://angular.io/guide/styleguide#style-06-03

@Component({
  ...
  host: {
    '(document:keypress)': 'handleKeyboardEvent($event)'
  }
})
export class AppComponent {
  handleKeyboardEvent(event: KeyboardEvent) {
    console.log(event);
  }
}

renderer.listen

import { Component, Renderer2 } from '@angular/core';

@Component({
  ...
})
export class AppComponent {
  globalListenFunc: Function;

  constructor(private renderer: Renderer2) {}

  ngOnInit() {
    this.globalListenFunc = this.renderer.listen('document', 'keypress', e => {
      console.log(e);
    });
  }

  ngOnDestroy() {
    // remove listener
    this.globalListenFunc();
  }
}

Observable.fromEvent

import { Observable } from 'rxjs/Observable';
import 'rxjs/add/observable/fromEvent';
import { Subscription } from 'rxjs/Subscription';

@Component({
  ...
})
export class AppComponent {
  subscription: Subscription;

  ngOnInit() {
    this.subscription = Observable.fromEvent(document, 'keypress').subscribe(e => {
      console.log(e);
    })
  }

  ngOnDestroy() {
    this.subscription.unsubscribe();
  }
}

Answer 2

Just to add to this in 2019 w Angular 8,

instead of keypress I had to use keydown

@HostListener('document:keypress', ['$event'])

to

@HostListener('document:keydown', ['$event'])

Working Stacklitz

Answer 3

yurzui's answer didn't work for me, it might be a different RC version, or it might be a mistake on my part. Either way, here's how I did it with my component in Angular2 RC4 (which is now quite outdated).

@Component({
    ...
    host: {
        '(document:keydown)': 'handleKeyboardEvents($event)'
    }
})
export class MyComponent {
    ...
    handleKeyboardEvents(event: KeyboardEvent) {
        this.key = event.which || event.keyCode;
    }
}

Answer 4

If you want to perform any event on any specific keyboard button press, in that case, you can use @HostListener. For this, you have to import HostListener in your component ts file.

import { HostListener } from '@angular/core';
then use below function anywhere in your component ts file.

@HostListener('document:keyup', ['$event'])
  handleDeleteKeyboardEvent(event: KeyboardEvent) {
    if(event.key === 'Delete')
    {
      // remove something...
    }
  }

Answer 5

Be aware "document:keypress" is deprecated. We should use document:keydown instead.

Link: https://developer.mozilla.org/fr/docs/Web/API/Document/keypress_event

Answer 6

I think this does the best job

https://angular.io/api/platform-browser/EventManager

for instance in app.component

constructor(private eventManager: EventManager) {
    const removeGlobalEventListener = this.eventManager.addGlobalEventListener(
      'document',
      'keypress',
      (ev) => {
        console.log('ev', ev);
      }
    );
  }

Answer 7

I struggeled a little bit on this one so; tshoemake provided the correct answer that also works for F keys. To prevent the F key from executing it's original browser action, like search, also call the preventDefault() method.

add the following includes

import { Component, HostListener } from '@angular/core';

and

@HostListener('document:keydown', ['$event'])
handleTheKeyboardEvent(event: KeyboardEvent) {
    switch (event.key) {
      case "F2":
        this.myF2Action();
        event.preventDefault();
        break;
    }
}