buffer

Buffer is a drop-in implementation of Node.js’s Buffer API that runs in the browser. It provides an API that is 100% identical to node’s Buffer, so npm modules that assume Buffer is available continue to work when bundled for the browser with tools like browserify, webpack, Vite, or esbuild.

Under the hood, Buffer instances are real Uint8Array objects whose prototype chain is extended with the full set of node Buffer methods. That means square-bracket indexing works, typed-array methods are available, and binary data manipulation stays fast without patching any browser globals or prototypes.

What You Get

• A Buffer class that mirrors the full Node.js Buffer API, including Buffer.from, Buffer.alloc, Buffer.concat, and every read/write accessor.
• Backing by native Uint8Array and ArrayBuffer for fast, memory-efficient binary data handling.
• Encoding and decoding across utf8, hex, base64, latin1, ascii, ucs2/utf16le, and base64url.
• TypeScript type definitions bundled via index.d.ts.
• A tiny footprint (about 6.75KB minified + gzipped) with no browser-prototype pollution.

Common Use Cases

• Running Node-oriented npm modules in the browser by letting a bundler polyfill the Buffer global.
• Reading and writing binary protocols, file formats, or network payloads on the client side.
• Converting between binary data and text encodings such as base64 and hex.
• Interoperating with Web APIs by treating a Buffer as the Uint8Array it already is.

Under The Hood

Architecture

The entire library lives in a single index.js module (~59KB) that defines a Buffer function subclassing Uint8Array. Instances are created as Uint8Array objects whose prototype is reset to Buffer.prototype, so every native typed-array capability is inherited while the node Buffer methods are layered on top. A Buffer.TYPED_ARRAY_SUPPORT feature check guards behavior on older engines, and static factories (Buffer.from, Buffer.alloc, Buffer.allocUnsafe, Buffer.concat) plus a large set of instance read/write accessors implement the node contract. The Uint8Array prototype itself is never modified and nothing is attached to window.

Tech Stack

Plain JavaScript with only two small runtime dependencies: base64-js for base64 encode/decode and ieee754 for float/double reads and writes. Bundled TypeScript definitions ship in index.d.ts. Dev tooling uses tape for tests, standard for linting, and browserify/airtap for cross-browser test runs, reflecting a deliberately minimal, dependency-light design.

Code Quality

The project carries a comprehensive test suite (over 1,300 lines across files like test/basic.js, test/from-string.js, test/write.js, and a test/node/ directory that mirrors buffer tests from node.js core). Code follows the standard style, uses explicit bounds and type checks in the accessor methods, and documents non-obvious feature detection inline. The single-file layout is dense but consistent and well-commented.

API Design Developer experience is excellent precisely because the API is not novel — it reproduces the widely-documented node Buffer surface exactly, so existing knowledge and the official node docs apply directly. Getting started requires no configuration: require('buffer').Buffer (or the bundler-provided global) is enough, and TypeScript users get full typings out of the box. Bracket-notation indexing and Uint8Array interop keep boilerplate to a minimum.