Convert a Uint8Array to a ReadableStream

The naive approach to creating a ReadableStream from a Uint8Array is to use the ReadableStream constructor and enqueue the entire array as a single chunk. For a large array, this may be undesirable because it doesn’t stream the data in smaller chunks.

const arr = new Uint8Array(64);
const stream = new ReadableStream({
  start(controller) {
    controller.enqueue(arr);
    controller.close();
  },
});

To stream the data in smaller chunks, first create a Blob instance from the Uint8Array, then use Blob.stream() to create a ReadableStream.

const arr = new Uint8Array(64);
const blob = new Blob([arr]);
const stream = blob.stream();

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

const arr = new Uint8Array(64);
const blob = new Blob([arr]);

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

See Binary Data.

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Convert a Uint8Array to a ReadableStream