When and why to use a 'tick' in Angular 2?

Question

I have seen the following is used in an Angular 2 component class:

setTimeout(()=>{}, 0);

That means, an empty function is called after

Answer 1

I'll add on the answer of Gunter as it is small at the moment.

He says :

setTimeout(()=>{}, 0); Causes Angular to run change detection for the whole application

This is because the setTimeout method has been monkey patched to be intercepted by angular which upon interception triggers change detection. In other words everytime setTimeout is called a change detection happens.

this could be done like this:

const temp = window.setTimeout;
window.setTimeout = (...args) => {
    temp(...args)
    angular.triggerChangeDetection(); // or w.e they use
}

So the 0 is to make the change detection happen immediately and the empty function is because we don't want to do anything.