how to make a function wait for another function javascript code example

Example 1: how to wait in javascript

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

//Pause for 1000 milliseconds

pause(1000)

Example 2: wait until a function finishes javascript

function firstFunction(_callback){
    // do some asynchronous work
    // and when the asynchronous stuff is complete
    _callback();    
}

function secondFunction(){
    // call first function and pass in a callback function which
    // first function runs when it has completed
    firstFunction(function() {
        console.log('huzzah, I\'m done!');
    });    
}