Guides · File System

Read a file to a Buffer

Read a file into a Node.js Buffer by passing the result of Bun.file().arrayBuffer() to Buffer.from().

The Bun.file() function accepts a path and returns a BunFile instance. BunFile extends Blob, so you can read the file lazily in a variety of formats.

To read the file into a Buffer, read it as an ArrayBuffer with .arrayBuffer(), then pass the result to Buffer.from().

index.ts

const path = "/path/to/package.json";
const file = Bun.file(path);

const arrbuf = await file.arrayBuffer();
const buffer = Buffer.from(arrbuf);

See Buffer for more on working with Buffer and other binary data formats in Bun.