What is ECMAScript

ECMAScript is the standardized specification that defines the JavaScript programming language. Think of it as the "rulebook" that describes how JavaScript should work.

The Relationship Between JavaScript and ECMAScript

JavaScript is the implementation of the ECMAScript specification. It's like saying:

• ECMAScript = the recipe
• JavaScript = the actual dish made from that recipe

Other implementations of ECMAScript include JScript (Microsoft's version) and ActionScript (used in Flash), but JavaScript is by far the most popular.

Why Does ECMAScript Exist?

When JavaScript was created by Brendan Eich at Netscape in 1995, it quickly became popular but also fragmented. Different browsers implemented it differently, causing compatibility nightmares for developers.

To solve this, Netscape submitted JavaScript to ECMA International (European Computer Manufacturers Association) in 1996 to create a standardized specification. This became ECMAScript.

ECMAScript Versions

The specification evolves over time with new versions:

• ES1 (1997) - First edition
• ES3 (1999) - Added regex, try/catch, more string methods
• ES5 (2009) - Strict mode, JSON support, array methods
• ES6/ES2015 - HUGE update: let/const, arrow functions, classes, promises, modules
• ES2016 - Array.includes(), exponentiation operator
• ES2017 - async/await, Object.entries()
• ES2018 - Rest/spread for objects, async iteration
• ES2019 - Array.flat(), Object.fromEntries()
• ES2020 - Optional chaining, nullish coalescing, BigInt
• ES2021 - String.replaceAll(), logical assignment operators
• ES2022 - Top-level await, class fields
• ES2023 - Array methods like findLast()
• ES2024 - Latest version

Since 2015, new versions are released annually, which is why you'll see names like "ES2023" or "ES2024."

What You Need to Know

When people say "ES6" or "modern JavaScript," they're usually referring to features added in ES2015 and later. These include:

// Arrow functions (ES6)
const add = (a, b) => a + b;

// Template literals (ES6)
const greeting = `Hello, ${name}!`;

// Destructuring (ES6)
const { firstName, lastName } = user;

// Optional chaining (ES2020)
const city = user?.address?.city;

// Async/await (ES2017)
async function fetchData() {
  const response = await fetch(url);
  return response.json();
}

In Practice

As a developer, you don't need to memorize which features came from which ECMAScript version. What matters is:

1. Understanding that ECMAScript is the standard behind JavaScript
2. Knowing that browsers and JavaScript engines (like V8, SpiderMonkey) implement these standards
3. Being aware that older browsers might not support newer ECMAScript features (which is why tools like Babel exist to transpile modern code to older versions)

So when someone asks "Do you know ES6?" they're really asking "Are you familiar with modern JavaScript features introduced in 2015 and beyond?"