es-versions-and-features.md

ES5, released on 2009
ES6, released on 2015 (very large scope of features)
Each next version is released once a year, and would include much less features.

ECMAScript 6 compatibility table - https://kangax.github.io/compat-table/es6/
ECMAScript 2016+ compatibility table - https://kangax.github.io/compat-table/es2016plus/

ES6 (ES 2015) features

• Block scoping with let and const
• Block-level functions
• Template strings
• Unicode support
• Function default parameters
• Rest parameters and spread operator
• Arrow functions with "this" being statically bound
• Tail call optimization
• Destructuring (inverse of construction)
• Classes, subclassable built-ins
• Iterators and generators
• Enhanced object literals
• Typed arrays
• Symbols
• Map and Set (weakmap and weakset)
• Promises
• Built-in types API additions
• binary and octal literals
• Proxies and reflection api

ES 2016-2017 features

Exploring ES2016 and ES2017 - https://exploringjs.com/es2016-es2017/index.html

• API enchancements: Array.prototype.include(), Object.getOwnPropertyDescriptors(), String.prototype.padEnd/padStart() (Node 8+)
• exponentiation operator: number ** pow
• async/await functions (Node 8+, Edge)
• trailing commas in function calls and signatures are lega (Node 8+, Edge)

ES 2018-2019 features

Exploring ES2018 and ES2019 - https://exploringjs.com/es2018-es2019/toc.html

• async iterators and generators (Node 10+, not supported in Edge)
• object rest/spread properties (Node 8+, not supported in Edge)
• "s" (dotAll) flag for regular expressions (Node 8+ Not supported in Edge, Firefox, TypeScript compiler.)
• Promise.prototype.finally (Node 10+, Edge 18+)
• Array.prototype.flat(), Array.prototype.flatMap() methods (Node 12+, TypeScript. Not supported by by Firefox, Edge, Babel compiler)
• Object.fromEntries() (Node 12+, TypeScript. Not supported: Babel, Edge, Firefox).