Lykn

Streams

Data processed in chunks rather than loaded entirely into memory. Essential for large files and real-time data.

Web Streams API

The modern standard — ReadableStream, WritableStream, TransformStream. Both Deno and modern Node.js support them:

(bind file (await (Deno:open "large-file.txt")))
(bind decoder (new TextDecoderStream))
(bind stream (file:readable:pipe-through decoder))

(for-await-of chunk stream
  (process-chunk chunk))

When Streams Matter

• Large files — reading a 1GB log file without loading it all into memory
• Real-time data — WebSocket messages, server-sent events
• Network responses — fetch returns a Response with a readable body stream

For most Lykn code, Deno:read-text-file and fetch handle the common cases. Streams are for when the data is too large or too continuous for buffering.