TypeScript - what type is f.e. setInterval

Question

If I'd like to assign a type to a variable that will later be assigned a setInterval like so:

this.autoSaveInterval = setInterval(function(){
      if(this.car.id){
        this.save();
      }
      else{
        this.create();
      }
    }.bind(this), 50000);

What type should be assigned to this.autosaveInterval vairable?

Answer 1

Late to the party, but the best type (especially since the type is opaque, we only care that we can pass it to clearInterval() later) might be the automatically deduced one, ie. something like:

ReturnType<typeof setInterval>

Answer 2

The type depends on which function you are going to use there are 2 overloads, the return type is marked in red bounding-box :

In order to use the one which returns number, please use :

window.setInterval(...)

Answer 3

The type is number;

private autoSaveInterval: number = setInterval(() => {
  console.log('123');
}, 5000);