ECMAScript Versions
JavaScript evolves through yearly ECMAScript editions, and this section tracks 8 of them — ES2025, ES2024, ES2023, ES2022, ES2021, ES2020, ES2019, ES2018. Each version page lists every feature that edition added to the language, with a description of what the feature does and a short code example showing it in action, from async iteration and optional catch binding in ES2019 through Array findLast, Object.groupBy, and the Set methods of more recent editions. Knowing which edition introduced a feature tells you which browsers and Node.js versions support it natively and whether you need a transpiler or polyfill. Follow the links from each feature to the full method reference — for example Array.prototype.map(), Array.prototype.filter(), Array.prototype.reduce(), Array.prototype.forEach(), Array.prototype.find(), Array.prototype.findIndex(), Array.prototype.findLast(), Array.prototype.some(), Array.prototype.every(), Array.prototype.includes(), Array.prototype.indexOf(), Array.prototype.push(), Array.prototype.pop(), Array.prototype.shift(), Array.prototype.unshift(), Array.prototype.slice(), Array.prototype.splice(), Array.prototype.concat(), Array.prototype.join(), Array.prototype.sort() — for complete syntax, parameters, and browser support details.