JavaScript - setInterval example

In this article, we would like to show you how to use setInterval in JavaScript.

Quick solution:

setInterval(() => {
  console.log('This will be called every 1000ms (1s)');
}, 1000);

setInterval is a method that takes in two arguments:

• a function which is being called every specific amount of time (interval),
• the interval time (in milliseconds).

setInterval is executed until it's stopped by clearInterval method which takes the interval as an argument.

Below we present some practical examples for better understanding.

1. Simple setInterval example

In this example, we create and call a simple function that displays some text every second.

Runnable example:

// ONLINE-RUNNER:browser;

setInterval(() => {
    console.log('This will be called every 1000ms (1s)');
  }, 1000);

2. Calling setInterval the specified amount of times

In this example, we create a function with setInterval that counts to 5 every second.

Runnable example:

// ONLINE-RUNNER:browser;

let x = 0;
let interval = setInterval(() => {
  console.log(x + 1);
  if (++x === 5) {
    clearInterval(interval);
  }
}, 1000);

3. Custom setInterval

In this example, we create customSetInterval that takes in three arguments:

• callback - a function to be called every specific amount of time,
• delay - interval time,
• numberOfTimes - how many times we want to call the callback function.

Runnable example:

// ONLINE-RUNNER:browser;

function foo(){
  console.log('some text');
  return;
};

function customSetInterval(callback, delay, numberOfTimes) {
  var x = 0;
  var interval = setInterval(() => {
    callback();
    if (++x === numberOfTimes) {
      clearInterval(interval);
    }
  }, delay);
};

customSetInterval(foo, 1000, 5);