JavaScript Glossary
The JavaScript glossary defines 20+ essential terms in plain language, each with a short definition followed by a longer explanation and a concrete code example. It covers the vocabulary you meet in documentation, error messages, and interviews — closures, hoisting, the prototype chain, the event loop, truthy and falsy values, strict mode, and more. Every term page also links to the methods and guides where the concept is used in practice, so the glossary works as a jumping-off point into the rest of the reference. Terms included: Closure, Hoisting, Event Loop, Prototype Chain, Temporal Dead Zone (TDZ), IIFE (Immediately Invoked Function Expression), Currying, Debouncing, Throttling, Pure Function, Scope, Rest Parameters, Spread Operator, Destructuring, Memoization, Callback Function, Async/Await, Module Pattern, Type Coercion, Immutability. If a definition mentions an unfamiliar API, look it up in the A–Z method index or run the example in the playground to see it behave live.