Languages / JavaScript Core
Collections
Arrays, Set, Map, and typed binary data.
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Arrays in JavaScript
Arrays are ordered, indexable lists and the default collection in most JavaScript code. This cheat sheet groups creation, mutation, search, and higher-order methods—including ES2023 non-mutating updates—so you can scan the API without rereading a tutorial.
Set in JavaScript
A Set stores unique values using SameValueZero equality—handy for deduplication, membership tests, and set algebra. This page covers construction, iteration, and the native union/intersection helpers added in ES2025.
Map and WeakMap
Map and WeakMap associate keys with values when object identity or garbage collection behavior matters more than string property names. This page compares APIs, iteration, and typical use cases next to plain objects and Set.
Typed arrays and ArrayBuffer
Typed arrays view raw bytes in an ArrayBuffer as integers or floats—used by WebGL, audio, binary protocols, and WASM interop. This page explains buffers, views, endianness, and how they differ from normal JavaScript arrays.