how to execute set of functions with interval in javascript code example

Example 1: javascript setinterval run immediately

foo()
setInterval(foo, delay)

// OR

function foo() {
   // ...
   setTimeout(foo, delay)
}
foo()

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);