Callback Function Simple Explaination

Callback Function

A callback function is a function that you pass into another function, so it can be called later when something happens.

Human example:

You order food at a restaurant.

You tell the waiter: “When my food is ready, call me.”

Here, calling you later is like a callback.

In programming:

function cookFood(callback) {
  console.log("Cooking food...");

  callback();
}

function tellCustomer() {
  console.log("Your food is ready!");
}

cookFood(tellCustomer);

Output:

Cooking food...
Your food is ready!

Here, tellCustomer is the callback function.

Because we pass it into cookFood(tellCustomer).

Then cookFood runs it later using callback();

Another common example:

setTimeout(function () {
  console.log("This runs after 2 seconds");
}, 2000);

Here, the function inside setTimeout is a callback. It runs after 2 seconds.