What is the JavaScript version of sleep()?

tl;dr

The JavaScript version of sleep() is setTimeout(). setTimeout() is a function that executes a given function after a specified number of milliseconds. For example, the following code will execute the sayHello() function after 1000 milliseconds (1 second):

setTimeout(sayHello, 1000);

function sayHello() {
    console.log('Hello!');
}

This can be extended as a utility with a Promise:

function sleep(ms) {
    return new Promise(resolve => setTimeout(resolve, ms));
}