@std/streams
Overview Jump to heading
Utilities for working with the Streams API.
Includes buffering and conversion.
import { toText } from "@std/streams";
import { assertEquals } from "@std/assert";
const stream = ReadableStream.from(["Hello, world!"]);
const text = await toText(stream);
assertEquals(text, "Hello, world!");
Add to your project Jump to heading
deno add jsr:@std/streams
See all symbols in @std/streams on
What are Web Streams? Jump to heading
Web Streams provide a standard way to handle streaming data in JavaScript. They allow you to process data piece by piece as it arrives, rather than waiting for the entire dataset to be available. This is particularly useful for handling large files, network requests, or any situation where data is produced over time.
Why use @std/streams? Jump to heading
Use for buffering, converting, and composing Web Streams efficiently.
Examples Jump to heading
import { copy, readerFromStreamReader, writeAll } from "@std/streams";
// Copy from a file to another file via streams
const r = await Deno.open("input.txt");
const w = await Deno.open("output.txt", {
create: true,
write: true,
truncate: true,
});
await copy(r, w);
r.close();
w.close();
// Convert a ReadableStreamDefaultReader to a Deno.Reader
const res = await fetch("https://deno.land");
const denoReader = readerFromStreamReader(res.body!.getReader());
await writeAll(
Deno.stdout,
new Uint8Array(await new Response(denoReader).arrayBuffer()),
);
Tips Jump to heading
- Prefer streaming for large payloads to reduce memory pressure.
- Use helpers like
toText,toArrayBuffer, anditerateReaderfor conversions.