set timeout pass this code example

Example 1: Pass functions, not strings, to setTimeout() and setInterval()

setInterval(doSomethingPeriodically, 1000);  
setTimeout(doSomethingAfterFiveSeconds, 5000);

Example 2: javascript this in settimeout

function func() {
  this.var = 5;
  
  this.changeVar = function() {
    setTimeout(() => { //Don't use function, use arrow function so 'this' refers to 'func' and not window
      this.var = 10;
    }, 1000);
  }
}

var a = new func();
a.changeVar();