Evolution of JavaScript Asynchronous Programming: Async/Await, Promises, and Callbacks ES6, ES7 ES8

Evolution of JavaScript Asynchronous Programming: Async/Await, Promises, and Callbacks ES6, ES7 ES8

1. In 1999, callbacks were introduced in Ecmascript to handle asynchronous operations. Callbacks are functions passed as parameters to a function, but they can lead to deeply nested and hard-to-understand code structures, commonly known as callback hell or Pyramid of Doom. 😫

2. To overcome the problem of callback hell, promises were introduced in ES6 in 2015. Promises provide a more readable and easier-to-use way of handling asynchronous code. They have three states: pending, fulfilled, or rejected. Promises are created using the promise constructor and can be chained with .then() and .catch() to handle fulfillment and rejection. ✨

3. However, even with promises, some developers still found the code structure with chains of .then() and .catch() slightly weird. In 2017, async/await was introduced to make the code look more synchronous. The async keyword is used to create a function that returns a promise, and inside this function, the await keyword is used to wait for the resolution of a promise. This makes the code look like synchronous code, which is more intuitive for many developers. 🚀

4. Asynchronous operations are tasks that take some time to finish, such as fetching data from a server, sending emails, or uploading files. These operations need to be handled differently from synchronous operations because they don't block the execution of the code. Instead, they allow the code to continue running while waiting for the asynchronous task to complete. ⏳

5. Callbacks were the initial approach to handle asynchronous operations in JavaScript. By passing a function as a parameter to another function, developers could specify what should happen once the asynchronous task is completed. However, this led to deeply nested and hard-to-read code structures, making it difficult to understand and maintain. 🔄

6. Promises were introduced to address the issues of callback hell. They provide a more structured and readable way to handle asynchronous code. With promises, developers can chain .then() and .catch() methods to handle the fulfillment or rejection of a promise, making the code easier to follow. Promises have become a widely adopted pattern in modern JavaScript development.

7. Async/await was introduced to further improve the readability and simplicity of asynchronous code. By using the async keyword to declare a function as asynchronous and the await keyword to pause the execution until a promise is resolved, developers can write asynchronous code that closely resembles synchronous code. This makes it easier to reason about and maintain, especially for developers coming from a synchronous programming background. 🎉

🔗 Dive Deeper:

00:00 - Intro
00:11 - 1999 - Callbacks
00:52 - 2015 - Promises
01:26 - 2017 - Async/Await

asynchronous js, async/await, await javascript, await async, async/await javascript, javascript async/await, asynchronous functions javascript, js async function, async function javascript, javascript async function, asynchronously javascript, js asynchronous, async javascript, async function, async js, js async, asynchronous javascript, asynchronous in javascript, javascript asynchronous, javascript asynchronous programming, asynchronous programming javascript, javascript synchronous, async js example, javascript asynchronous code, javascript asynchronous or synchronous, is javascript async or sync, is javascript asynchronous or synchronous, javascript is asynchronous or synchronous, javascript async or sync, synchronous and asynchronous in javascript, what is synchronous and asynchronous in javascript, javascript asynchronous vs synchronous, sync and async in javascript, js asynchronous or synchronous