The Node.js Buffer API predates the introduction of ArrayBuffer into the JavaScript language. Bun implements both.

Use the static Buffer.from() method to create a Buffer from an ArrayBuffer.

const arrBuffer = new ArrayBuffer(64);
const nodeBuffer = Buffer.from(arrBuffer);

To create a Buffer that only views a portion of the underlying buffer, pass the offset and length to Buffer.from().

const arrBuffer = new ArrayBuffer(64);
const nodeBuffer = Buffer.from(arrBuffer, 0, 16); // view first 16 bytes

See Binary Data.