ES6

ES6, also known as ECMAScript 2015, is the sixth major edition of the ECMAScript standard for JavaScript. Formalized in 2015 by the TC39 committee, it represents a broad modernization of the language. ES6 introduced substantial language and API improvements aimed at increasing developer productivity while preserving compatibility with existing JavaScript code and environments.

Notable features include block-scoped variables declared with let and const, arrow functions, classes, modules with import and export syntax, and improved object literals. It added template literals for easier string construction, default parameters, and destructuring assignments. The language gained iterators and the for...of loop, as well as maps, sets, and weak maps for data collections. Rest and spread operators enabled flexible function arguments and array manipulation. Promises provided a native mechanism for asynchronous operations, and symbols offered a new primitive type. Other enhancements included computed property names, enhanced class syntax, and the ability to declare and consume modules in a standard way. Generators and other advanced features also appeared, along with new APIs and utilities such as Reflect and new array helpers.

Since its release, browser and runtime support has grown extensively, and many features are now standard in modern environments. Transpilers such as Babel and TypeScript allow developers to write ES6 code for older engines. ES6 is widely regarded as the baseline for modern JavaScript, forming the foundation for subsequent revisions (ES2016 onward) and modern tooling.