Module 9 · 8 chapters

Modern JavaScript (ES6+)

ES2015 (ES6) and the releases that followed added the syntax modern JavaScript is written in today. let and const replaced var, template literals replaced string concatenation, and import/export replaced global script tags.

This module covers the ES6+ features you will see in every codebase and job interview. Each chapter shows the old pattern alongside the modern equivalent so you can read legacy code and write idiomatic JavaScript.

Chapters in this module

let and constES6 replaced var with let and const — block-scoped bindings that behave predictably in loops, branches, and modules. Use const by default; reach for let when reassignment is intentional.
Template LiteralsLearn Template Literals in JavaScript — covering Interpolation, Multiline Strings, Expressions, Tagged Templates with interactive visual examples and step-by-step explanations.
Default ParametersLearn Default Parameters in JavaScript — covering Basics, Expressions as Defaults, Gotchas, Patterns with interactive visual examples and step-by-step explanations.
ModulesLearn Modules in JavaScript — covering Named Exports, Default Exports, Import Patterns, Dynamic Imports with interactive visual examples and step-by-step explanations.
Spread OperatorLearn Spread Operator in JavaScript — covering Array Spread, Object Spread, Copying, Merging with interactive visual examples and step-by-step explanations.
Rest ParametersLearn Rest Parameters in JavaScript — covering Basics, vs arguments, With Other Params, In Destructuring with interactive visual examples and step-by-step explanations.
Optional ChainingLearn Optional Chaining in JavaScript — covering Property Access, Method Calls, Dynamic Properties, Short-Circuiting with interactive visual examples and step-by-step explanations.
Nullish CoalescingLearn Nullish Coalescing in JavaScript — covering Basics, vs || (OR), ??= Assignment, With ?. with interactive visual examples and step-by-step explanations.

Start with let and const