Angular 2 change event on every keypress

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.

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);
}

The (keyup) event is your best bet.

Let's see why:

(change) like you mentioned triggers only when the input loses focus, hence is of limited use.
(keypress) triggers on key presses but doesn't trigger on certain keystrokes like the backspace.
(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.
(keyup) is your best bet as it triggers every time a key push event has completed, hence this also includes the most recent character.