es2017

ECMAScript 2017, commonly referred to as ES2017, is the eighth edition of the ECMA-262 standard for the JavaScript language. It was published in 2017 by Ecma International and coordinated by the TC39 committee. The edition standardizes a set of features intended to improve developer productivity, particularly around asynchronous programming and data handling.

Notable features include: async functions and the await operator, which simplify asynchronous code by letting it read synchronously and by returning promises; Shared memory and atomic operations via SharedArrayBuffer and the Atomics object to enable memory sharing between workers; Object.values and Object.entries for convenient enumeration of an object's own enumerable properties; Object.getOwnPropertyDescriptors for retrieving property descriptors; String.prototype.padStart and padEnd for padding strings; and the addition of trailing commas in function parameter lists and function calls to ease editing and version control diffs.

Implementation and compatibility: the features were implemented in major JavaScript engines (V8, SpiderMonkey, JavaScriptCore) during 2017–2018. They are broadly supported in modern browsers and Node.js, with older environments requiring transpilation or polyfills. ES2017's changes have influenced JavaScript development by making asynchronous code more approachable and by providing practical object utilities that are widely used in codebases.

ES2017 was followed by ES2018, which expanded the language with features such as asynchronous iteration and object rest/spread properties. The edition represents a step in the ongoing evolution of JavaScript toward more expressive and safer programming patterns.