Javascript / Angular：超时包装在具有布尔值的函数中不起作用

Question

In the View I have this condition:

    <h3 *ngIf="show">{{users.result}}</h3>

In the TypeScript logic I have:

show=false; <----as a property

And the the following function:

timeOut(seconds: number, value:boolean) {
   value = true;      
    setTimeout(
      function() {
        value = false;
      }.bind(this),
      seconds
    );
  }

But when I call it, like this:

console.log(this.timeOut(3000, this.show));

the property `this.show´ gets undefined, but the seconds passed as argument work. I'm missing something and I can't figure out what... Can anyone give a help?

Answer 1

As i see:

• First of all you console logging function call without result .
• When you pass the boolean value into the function params it's being copied , so when you change the value inside the function, it doesn't affect the outside variable/field.
• This is very specialized use case, so you do not need to extract it to different function.

My suggestion - just put setTimeout call with arrow function into some component's method like ngAfterViewInit or in event handler method :

ngAfterViewInit() {
   setTimeout(() => this.show = true, 3000)
}

Hope that helps.