Learning Node.js Development

The callback function

Before we get started making the HTTPS request, let's talk about callback functions, and we have already used them. Refer to the following code (we used it in the previous section):

console.log('Starting app');setTimeout(() => {  console.log('Inside of callback');}, 2000);setTimeout(() => {  console.log('Second setTimeout');}, 0);console.log('Finishing up');

Inside the setTimeout function we used a callback function. In general, a callback function is defined as a function that gets passed as an argument to another function and is executed after some event happens. Now this is a general definition, there is no strict definition in JavaScript, but it does satisfy the function in this case:

setTimeout(() => { console.log('Inside ...