Modern JavaScript: Everything you missed over the last 10 years (2020)
This 2020 article provides a comprehensive overview of JavaScript features introduced in ES2015 (ES6) and later, covering key additions like let/const, arrow functions, template literals, destructuring, modules, classes, promises, async/await, and more, aimed at developers who haven't kept up with the language's rapid evolution over the past decade.
Background
JavaScript (JS) is the programming language that runs in every web browser, making websites interactive. For years, JS had a reputation for being quirky and limited. Then in 2015, a major update called ES6 (ECMAScript 2015) arrived, and the language has been evolving yearly ever since — but many developers who learned JS before 2015 missed these changes. This 2020 article rounds up the key modern features: `let` and `const` (better ways to declare variables instead of the old `var`), arrow functions (shorter function syntax), template literals (embedding variables in strings with backticks), destructuring (pulling values out of objects/arrays in one line), spread/rest operators (`...`), promises and async/await (cleaner ways to handle delayed operations), classes (syntax for object-oriented patterns), and modules (importing/exporting code between files). Understanding these features matters because nearly all modern JavaScript code — including every major framework like React, Vue, and Node.js backends — relies on them.