A function passed as an argument to another function that is called after the function finishes executing. Similar to Continuation. When you’re done, call this next

  • Reading files
  • Network requests
  • Interacting with databases

Example

 
sum(2,3,displayConsole);
 
function sum(x, y, callback){
	let result = x+y;
	callback(result);
}
 
function displayConsole(result){
	console.log(result);
}