debounce to get a value input in angular2

Question

I want to get a value from an input text after a few time (many millisecond or seconds) in angular 2, when a custom write an input but without waiting him to click a button.

I have tried this, but even when I use debounceTime, value is send in every keypress.

I try to learn about debounce and observable and this is what I understand, Can anyone please help me to fix my code:

component.html:

<md-card-title *ngIf="!edit">{{card.title}}</md-card-title>
 <input *ngIf="edit" type="text" [(ngModel)]="card.title" (ngModelChange)='rename()'/>

component.ts

newTitle: string;
modelChanged: Subject < string > = new Subject < string > ();

constructor()
this.modelChanged
  .debounceTime(500) //before emitting last event
  .distinctUntilChanged()
  .subscribe(model => this.newTitle = model);
}

rename(): void {
  this.renameRequest.emit(this.newTitle);
}

Answer 1

Well, there is lot's of ways to achieve that, but here is one way :

<input *ngIf="edit" type="text" #input="ngModel" [(ngModel)]="card.title" (ngModelChange)='rename()'/>

And inside your class

newTitle : string;
@ViewChild('input') input;
constructor()

}

ngAfterViewInit(){
       this.input.valueChanges
             .pipe(debounceTime(500)) before emitting last event
             .pipe(distinctUntilChanged())
             .subscribe(model => (value)=>{
                   console.log('delayed key press value',value);
                    this.rename(value)
              });

}

rename(value): void {
    this.renameRequest.emit(value);
}

Here is the Plunker

You can even subscribe to modelChange like bellow :

ngAfterViewInit(){
       this.input.update // this is (modelChange)
             .pipe(debounceTime(500)) before emitting last event
             .pipe(distinctUntilChanged()) 
             .subscribe(model => (value)=>{
                   console.log('delayed key press value',value);
              });

}