How can a variable always be checked?

Ionic Framework ionic-v3
1

Hello i am loolinhg for a solution for that ;

I have integer variable and i always want to check it weather it is zero or not ?
like subscribe it !

BUT how can i do this

Thanks in Advance

2

Where do you want to do this? If “from a template”, then just let Angular’s change detection deal with it:

<div *ngIf="!foo">foo is zero</div>
3

what about at ts file ? it s like kind of a state controll but basic just one variable

4

Check it in your constructor for example, eg, if this.myvalue != “null || undefined” { this.myvalue = something }.

5

You can check that variable within your ts file.

import {Observable } from 'rxjs/Rx';
@Component({
  ...
})
constructor(){
    Observable.interval(100).subscribe(x => {
        if(variable == 0)
        {
            //do this
        }
        else 
        {   //do that 
        }
    });
}
1 Like
6

However this checks only once ! it need to be like state controller .

7

@techsnake you’re right, then work with @amitk04 answer just above :slight_smile: (an observable or promise)

1 Like
8

Please describe what you are actually trying to achieve. Periodically polling like the suggestion given above involving interval is a wasteful use of resources.