Why Promises Exist in JavaScript (The Questions I Had as a Beginner)

Understanding the nuances of asynchronous programming, particularly with callbacks and promises, is crucial for writing maintainable and efficient JavaScript code. Here’s a detailed breakdown to help clarify these concepts:

Why Callbacks Break at Scale

Initial Confusion

When you first encounter asynchronous operations in JavaScript, using callbacks seems straightforward:

javascript
 
1function step1(callback) {
2  // Some async operation
3  setTimeout(() => callback(null, 'result'), 1000);
4}
5
6step1((err, result) => {
7  if (err) throw err;
8  console.log(result);
9
10  step2((err, result) => {
11    if (err) throw err;
12    console.log(result);
13
14    step3((err, result) => {
15      if (err) throw err;
16      console.log(result);
17    });
18  });
19});

Issues with Nested Callbacks

As the number of asynchronous operations increases, the code becomes deeply nested and difficult to read. This is known as "callback hell" or "pyramid of doom":

javascript
 
1step1((err, result) => {
2  if (err) throw err;
3  console.log(result);
4
5  step2((err, result) => {
6    if (err) throw
7
8[Read the full article at DEV Community](https://dev.to/punavwalke/why-promises-exist-in-javascript-the-questions-i-had-as-a-beginner-je0)
9
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