Timers

Timers are used to schedule the execution of a particular callback after a specific delay. There are two primary methods to set up such delayed execution: setTimeout and setInterval. The setTimeout() function is used to schedule the execution of a specific callback after a delay, while setInterval is used to schedule the repeated execution of a callback. The setTimeout function is useful to perform tasks that need to be scheduled such as housekeeping. Consider the following example:

setTimeout(function() {
  console.log("This is just one time delay");
},1000);
var count=0;
var t = setInterval(function() {
  count++;
  console.log(count);
  if (count> 5){
    clearInterval(t);
  }
}, 2000 );

First, we are using setTimeout() to execute a callback (the anonymous function) after a delay of 1,000 ms. This is just a one-time schedule for this callback. We scheduled the repeated execution of the callback using setInterval(). Note that we are assigning the value returned by setInterval() in a variable t—we can use this reference in clearInterval() to clear this schedule.