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The Buffer API in Node.js is one of the most commonly used Node.js APIs for manipulating binary data. Every Buffer instance extends from the standard Uint8Array class, but adds a range of unique capabilities such as built-in base64 and hex encoding/decoding, byte-order manipulation, and encoding-aware substring searching.

import { Buffer } from 'node:buffer';
const buf = Buffer.from('hello world', 'utf8');
// Prints: 68656c6c6f20776f726c64
// Prints: aGVsbG8gd29ybGQ=

A Buffer extends from Uint8Array. Therefore, it can be used in any Workers API that currently accepts Uint8Array, such as creating a new Response:

const response = new Response(Buffer.from("hello world"));

You can also use the Buffer API when interacting with streams:

const writable = getWritableStreamSomehow();
const writer = writable.getWriter();
writer.write(Buffer.from("hello world"));

Refer to the Node.js documentation for Buffer for more information.