A callback the function is a function that is passed to another function as an argument and is executed after some operation has been completed. Below is an example of a simple callback function that logs to the console after some operations have been completed.
function modifyArray(arr, callback) {
// do something to arr here
arr.push(100);
// then execute the callback function that was passed
callback();
}
var arr = [1, 2, 3, 4, 5];
modifyArray(arr, function() {
console.log("array has been modified", arr);
});
