ECMAScript

ECMAScript is a standardized specification for a high-level, dynamically typed programming language used for web scripting. It is published by ECMA International as ECMA-262 and is maintained by the TC39 committee. Implementations of the ECMAScript specification form the core of JavaScript and related languages used in browsers, Node.js, and other runtimes.

Its origins lie in Netscape's JavaScript, with influence from Java. The first edition of ECMA-262 was published in 1997. The standard has undergone regular revisions; notable milestones include ES3 in 1999, ES5 in 2009 (introducing strict mode, JSON, getters/setters), ES2015 also known as ES6 in 2015 (introducing classes, modules, let/const, arrows, promises), and subsequent annual editions ES2016 through ES2023 adding features such as async/await, exponentiation, nullish coalescing, optional chaining, dynamic import, and more.

ECMAScript defines the language core: syntax, types, operators, statements, and standard built-in objects and modules. It supports first-class functions, prototype-based object orientation, lexical scoping, and a comprehensive standard library. Features added in modern editions include modules, classes, arrow functions, template literals, destructuring, generators, iterators, promises, and async functions.

Implementation and tooling: Major JavaScript engines implement the standard, including V8 (Google Chrome, Node.js), SpiderMonkey (Mozilla), and JavaScriptCore (Safari). Because browsers and runtimes may implement features at different rates, transpilers such as Babel and language extensions like TypeScript are used to target older ECMAScript versions. The ECMAScript standard is maintained by the TC39 committee under ECMA International.