Angular 2 change event on every keypress

Question

The change event is only called after the focus of the input has changed. How can I make it so that the event fires on every keypress?

<input type="text" [(ngModel)]="mymodel" (change)="valuechange($event)" />
{{mymodel}}

The second binding changes on every keypress btw.

Answer 1

A different way to handle such cases is to use formControl and subscribe to its valueChanges when your component is initialized, which will allow you to use rxjs operators for advanced requirements like performing http requests, apply a debounce until user finish writing a sentence, take last value and omit previous value, etc.

import { Component, OnInit } from '@angular/core';
import { FormControl } from '@angular/forms';
import { debounceTime, distinctUntilChanged } from 'rxjs/operators';

@Component({
  selector: 'some-selector',
  template: `
    <input type="text" [formControl]="searchControl" placeholder="search">
  `
})
export class SomeComponent implements OnInit {
  public searchControl: FormControl;
  public debounce: number = 400;

  ngOnInit() {
    this.searchControl = new FormControl('');
    this.searchControl.valueChanges
      .pipe(debounceTime(this.debounce), distinctUntilChanged())
      .subscribe(query => {
        console.log(query);
      });
  }
}

Answer 2

<input type="text" [ngModel]="mymodel" (keypress)="mymodel=$event.target.value"/>
{{mymodel}}

Update

https://developer.mozilla.org/en-US/docs/Web/API/Element/keypress_event

Warning: Since this event has been deprecated, you should use beforeinput or keydown instead.

Answer 3

This question has been answered with multiple ways. However, if you would like to look at another way, specific to adding some delay before you take any action on change event then you can use the debounceTime() method with angular form valuechanges(). This code need to be added in ngOnInit() hook or create a seprate method and call it from ngOnInit().

  ngOnInit(): void {
    this.formNameInputChange();
  }

  formNameInputChange(){
    const name = this.homeForm.get('name'); // Form Control Name
    name?.valueChanges.pipe(debounceTime(1000)).subscribe(value => {
      alert(value);
    });
  }
  // this is reactive way..
  homeForm = this.fb.group({
    name:['']
  });

Answer 4

I managed to get this solved in Angular 11 by using the below code:

<input type="number" min="0" max="50" [value]="input.to" name="to"
        (input)="input.to=$event.target.value; experienceToAndFrom()">

And, the experienceToAndFrom() is a method in my component.

PS: I tried all the above solutions, but didn't work.

Answer 5

I've been using keyup on a number field, but today I noticed in chrome the input has up/down buttons to increase/decrease the value which aren't recognized by keyup.

My solution is to use keyup and change together:

(keyup)="unitsChanged[i] = true" (change)="unitsChanged[i] = true"

Initial tests indicate this works fine, will post back if any bugs found after further testing.

Answer 6

For Reactive Forms, you can subscribe to the changes made to all fields or just a particular field.

Get all changes of a FormGroup:

this.orderForm.valueChanges.subscribe(value => {
    console.dir(value);
});

Get the change of a specific field:

this.orderForm.get('orderPriority').valueChanges.subscribe(value => {
    console.log(value);
  });

Answer 7

I just used the event input and it worked fine as follows:

in .html file :

<input type="text" class="form-control" (input)="onSearchChange($event.target.value)">

in .ts file :

onSearchChange(searchValue: string): void {  
  console.log(searchValue);
}

Answer 8

The (keyup) event is your best bet.

Let's see why:

1. (change) like you mentioned triggers only when the input loses focus, hence is of limited use.
2. (keypress) triggers on key presses but doesn't trigger on certain keystrokes like the backspace.
3. (keydown) triggers every time a key is pushed down. Hence always lags by 1 character; as it gets the element state before the keystroke was registered.
4. (keyup) is your best bet as it triggers every time a key push event has completed, hence this also includes the most recent character.

So (keyup) is the safest to go with because it...

• registers an event on every keystroke unlike (change) event
• includes the keys that (keypress) ignores
• has no lag unlike the (keydown) event

Answer 9

In my case, the solution is:

[ngModel]="X?.Y" (ngModelChange)="X.Y=$event"

Answer 10

Use ngModelChange by breaking up the [(x)] syntax into its two pieces, i.e., property databinding and event binding:

<input type="text" [ngModel]="mymodel" (ngModelChange)="valuechange($event)" />
{{mymodel}}

valuechange(newValue) {
  mymodel = newValue;
  console.log(newValue)
}

It works for the backspace key too.

Answer 11

What you're looking for is

<input type="text" [(ngModel)]="mymodel" (keyup)="valuechange()" />
{{mymodel}}

Then do whatever you want with the data by accessing the bound this.mymodel in your .ts file.

Answer 12

The secret event that keeps angular ngModel synchronous is the event call input. Hence the best answer to your question should be:

<input type="text" [(ngModel)]="mymodel" (input)="valuechange($event)" />
{{mymodel}}

Answer 13

<input type="text" (keypress)="myMethod(myInput.value)" #myInput />

archive .ts

myMethod(value:string){
...
...
}