The Evolution of JavaScript and Why It Matters

by Hexagon, 3 minutes read javascript guide

Understanding the past and how we got here can give us good hints about where we're going. Let's dig into JavaScript's history and how it's grown over time. Knowing this stuff will help us when we move on to more complicated topics like Promises, template literals, async/await, and the latest JavaScript features.

How Did JavaScript Start?

JavaScript was created back in 1995 by Brendan Eich while he was working at Netscape. It was meant to be a simple language to add interactivity to websites. Eich put together the first version in just 10 days. Since then, it quickly became a cornerstone for both front-end and back-end web development.

ECMAScript: The Rule Book

ECMAScript is the set of rules that JavaScript follows. The group that came up with these rules, ECMA International, first put them out in 1997. We've had several updates to ECMAScript since then, adding new features and improving the language.

Big Changes Over Time

  • ES3 (1999): Gave us features like try and catch for handling errors.

  • ES5 (2009): Added methods to work with JSON data and new ways to deal with objects.

  • ES6 / ES2015: Big update that added let and const, arrow functions, template literals, and more.

  • ES2016: Introduced the exponentiation operator (**) and Array.prototype.includes

  • ES2017: Added async/await, Object.values, Object.entries, String.padStart/padEnd

  • ES2018: Brought in rest/spread properties, Promise.finally, and asynchronous iteration.

  • ES2019: Added Array.flat/flatMap, Object.fromEntries, String.trimStart/trimEnd, and optional catch binding.

  • ES11 / ES2020: Introduced optional chaining (?.), nullish coalescing operator (??`),`BigInt, and dynamic import.

A great way for you to check feature compability with your intended runtime/browser is to check MDN, this is an example of async browser/runtime compability

CommonJS to ES Modules: Time to Switch

CommonJS was the go-to way to include modules in JavaScript, especially in Node.js. But it had its limits. Now we're moving to ES modules, which are more flexible and better aligned with ECMAScript rules.

// CommonJS
const fs = require("fs");

// ES Modules
import fs from "fs";

Switching to ES modules will make your code cleaner and easier to manage, especially as you work on larger projects. It also optimizes for both static analysis and tree shaking. This can lead to better-optimized bundles and cleaner codebases, making it easier to get rid of outdated dependencies and polyfills.

A note on polyfills

In the world of web development, compatibility has always been a primary concern. Due to the inconsistencies between browser versions and their support for JavaScript features, developers often turned to polyfills. A polyfill is a piece of code that provides modern functionality on older browsers that do not natively support it. They essentially "fill in" the gaps where browser support is lacking.

There was a time when polyfills were essential, but now, most modern browsers have gotten their act together and offer consistent JavaScript support. So, the need for polyfills has gone down.

Likewise, people used to rely a lot on libraries to make JavaScript easier. But as JavaScript got better, many of these libraries fell by the wayside. Nowadays, you can often get the job done using just built-in JavaScript features.

Embrace Built-in Features

One example of a big shift in JavaScript is the transition from custom AJAX libraries to the native fetch API in JavaScript. Earlier, developers might have leaned on jQuery's $.ajax or other similar custom solutions to make asynchronous HTTP requests. Today, the built-in fetch function gives a more standardized way to achieve the same, without relying on any external libraries.

Here's why focusing on built-in features in JavaScript is a good idea:

  • More Optimized: Native features are generally faster and more efficient than their library counterparts.

  • Well-Supported: Being part of the language specification, you can expect consistent support across all modern browsers.

  • Less Redundant: Using built-in features reduces the need for external libraries, ensuring faster page loads and optimized performance.

Staying Updated

As you continue to work with JavaScript, it's important to stay in the loop about the latest features and updates. The JavaScript landscape is always changing, and what was considered a best practice yesterday might not hold up today. Make a habit of checking out official documentation, following key developers on social media, and participating in coding communities. This will not only keep your skills fresh but also let you take advantage of new and more efficient ways of doing things.

Have a look at for full history of ECMAScript, and current proposals.

Working with Arrays Strings and Numbers