call keyup event with delay in angular

user_7706936 0
Viewed 18832

I have text box and assigned to it keyup event a search function but I want it to happen with delay, not on every keypress

here is the html code :

<input type="text" [(ngModel)]="searchedKPI" (keyup)="searchConfigTree()">

and here is ts code :

list = list.filter(item => item.label.toLocaleLowerCase().includes(this.searchedKPI.toLocaleLowerCase())).slice();

and here is the example I wanted to search "text" string but the event happens 4 times, I want to this happens once only for "text" string :

enter image description here

what the solution?

angular typescript javascript
4 Answers

Welcome to the Observable's world. Just use Observable to get the desired result. Get the reference of your input in the component and use this code. debounceTime will let the event to trigger at least after 1 second from the previous trigger. It will let you not to fire on every keyup when user types fast.

Observable.fromEvent(yourInput, 'keyup').debounceTime(1000).subscribe(value => /* */)

In the subscribe method you can write your logic. The value is the value of the input.

user_54969730

View template.html 

<input type="text" [(ngModel)]="searchedKPI" (keyup)="searchConfigTree()" #something>

component.ts (do not forget implement the AfterViewInit)

     source: any;
     @ViewChild("something") something:ElementRef; 

     ngAfterViewInit(): void {
                this.source = fromEvent(this.something.nativeElement, 'keyup');
                this.source.pipe(debounceTime(1200)).subscribe(c => 
                {
                          list = list.filter(item => item.label.toLocaleLowerCase().includes(this.searchedKPI.toLocaleLowerCase())).slice();
                }
                );
              }
user_20436570

This solution works for me

View Template.html

<input type="text" placeholder="Filter..." class="form-control" [(ngModel)]="filter" (input)="searchChange($event.target.value, true)">
<button class="btn btn-primary" type="button" (click)="searchChange(filter, false)"><i class="fa fa-search"></i></button>

Comonent.ts

  filter= '';
  private timer: any;

  searchChange(filter: string, to = false) {
    filter = filter.toLowerCase();

    if (to) {
      clearTimeout(this.timer);

      this.timer = setTimeout(() => {
        this.valuesFilter = this.allValues.filter(f => f.field.toLowerCase().includes(filter));
      }, 400);
    } else {
      this.valuesFilter = this.allValues.filter(f => f.field.toLowerCase().includes(filter));
    }
  }
user_140000620

cant we use timeout function?

(keyup)="keyupFunc()" --> html
keyup() {
       timeout((your function code), delay_time_you_need);
   } --> ts
user_155908390
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