如何在angular4中将数字推送到数组中？

Question

I am trying to push a number in an array when i click on a button but it does not seem to work.

In my app.component.html:-

<div>
    <label>Number of days:- 
        <input [(ngModel)]="numDay"><button type="button" class="btn btn-primary btn-lg" (click)="onClickMe()">OK</button>
    </label>
</div>
<p>{{dayNum}}</p>

In my app.component.ts :-

  private numDay : number;
  private master1 : number;
  private dayNum = [2,3];

  ngOnInit() {
    this.dayNum.push(8);  
  }
  onClickMe() {
    this.master1 = (this.numRace*1);
    this.dayNum.push(99); // <<<<--- This does not seem to work
  };

You can check my code in Plunker:

http://plnkr.co/edit/jM3NDu7V3AjzOWeuCoDi?p=preview

Thank you for your help

Answer 1

I've had this problem before and it turned out to be to do with change detection in Angular.

My solution was to do a shallow copy instead of a push. But a *ngFor may solve this also.

this.dayNum = [...this.dayNum, 9];