Convert a Buffer to a ReadableStream

The naive approach to creating a ReadableStream from a Buffer is to use the ReadableStream constructor and enqueue the entire array as a single chunk. For a large buffer, this approach may be undesirable because it doesn't stream the data in smaller chunks.

const buf = Buffer.from("hello world");
const stream = new ReadableStream({
  start(controller) {
    controller.enqueue(buf);
    controller.close();
  },
});

To stream the data in smaller chunks, first create a Blob instance from the Buffer, then use Blob.stream() to create a ReadableStream.

const buf = Buffer.from("hello world");
const blob = new Blob([buf]);
const stream = blob.stream();

Pass a number to .stream() to set the chunk size.

const buf = Buffer.from("hello world");
const blob = new Blob([buf]);

// set chunk size of 1024 bytes
const stream = blob.stream(1024);

See Binary Data.