javascript wait to call setInterval until called code example

Example 1: setinterval vs settimeout js

var intervalID = setInterval(alert, 1000); // Will alert every second.
// clearInterval(intervalID); // Will clear the timer.

setTimeout(alert, 1000); // Will alert once, after a second.
setInterval(function(){ 
	console.log("Oooo Yeaaa!");
}, 2000);//run this thang every 2 seconds

Example 2: how to do a function after a set interval js

function sayHi() {
  alert('Hello');
}
//Do a function at a set interval continuously
setTimeout(sayHi, 1000);
//Do a function once after a set interval
setTimeout(sayHi, 1000);