How to pass a callback as a parameter into another function

Question

I\'m new to ajax and callback functions, please forgive me if i get the concepts all wrong.

Problem: Could i send a callbackfunction

Answer 1

You can use JavaScript CallBak like this:

var a;

function function1(callback) {
 console.log("First comeplete");
 a = "Some value";
 callback();
}
function function2(){
 console.log("Second comeplete:", a);
}


function1(function2);

Or Java Script Promise:

let promise = new Promise(function(resolve, reject) { 
  // do function1 job
  let a = "Your assign value"
  resolve(a);
});

promise.then(             

function(a) {
 // do function2 job with function1 return value;
 console.log("Second comeplete:", a);
},
function(error) { 
 console.log("Error found");
});