@hsblabs/web-stream-extras

@hsblabs/web-stream-extras is a TypeScript utility library for the WHATWG Streams API.

It helps you work with ReadableStream, TransformStream, and Uint8Array data in browsers and Node.js runtimes that support Web Streams. The package includes practical stream helpers for byte-oriented workflows, plus an encryption subpath for encrypted byte streams.

What This Package Is For

Use this package when you need to:

• build or consume ReadableStream<Uint8Array> pipelines
• collect byte streams into a single Uint8Array
• convert between strings, Uint8Array, and ArrayBuffer
• build custom TransformStream utilities for binary data
• encrypt or decrypt byte streams with the Web Streams API

This makes it a good fit for:

• Web Streams API utilities
• WHATWG stream processing
• browser and Node.js stream helpers
• byte stream and binary data handling
• encrypted file streams and encrypted payload pipelines

Installation

npm install @hsblabs/web-stream-extras

pnpm add @hsblabs/web-stream-extras

bun add @hsblabs/web-stream-extras

yarn add @hsblabs/web-stream-extras

Quick Start

Read and collect a byte stream

import {
  binaryToString,
  readAllBytes,
  readableFromChunks,
  stringToBinary,
} from "@hsblabs/web-stream-extras";

const input = readableFromChunks([
  stringToBinary("hello"),
  stringToBinary(" "),
  stringToBinary("world"),
]);

const output = await readAllBytes(input);

console.log(binaryToString(output)); // "hello world"

Encrypt and decrypt a stream

import {
  readAllBytes,
  readableFromChunks,
  stringToBinary,
} from "@hsblabs/web-stream-extras";
import {
  decryptStream,
  encryptStream,
} from "@hsblabs/web-stream-extras/encryption";

const encKey = crypto.getRandomValues(new Uint8Array(32));
const plaintext = readableFromChunks(stringToBinary("secret payload"));

const encrypted = encryptStream(encKey, plaintext);
const decrypted = decryptStream(encKey, encrypted);
const result = await readAllBytes(decrypted);

console.log(new TextDecoder().decode(result)); // "secret payload"

Why Use It

This package focuses on a small set of utilities that are useful in real byte-stream pipelines:

• readableFromChunks() for quickly creating a ReadableStream
• readAllChunks() and readAllBytes() for consuming a stream
• ByteTransformStream for building binary TransformStream wrappers
• Uint8Array and ArrayBuffer helpers for consistent byte handling
• encryption helpers for stream encryption without changing your stream-first API style

The goal is to keep Web Streams code simple, predictable, and easy to compose.

API Overview

Root package

The root package provides:

• Web Streams utilities for creating and consuming streams
• byte conversion helpers for Uint8Array, strings, and ArrayBuffer
• small building blocks for binary transform pipelines

Representative exports include:

• readableFromChunks
• readAllChunks
• readAllBytes
• ByteTransformStream
• ByteQueue
• stringToBinary
• binaryToString
• toU8Array
• toArrayBuffer

@hsblabs/web-stream-extras/encryption

The encryption subpath provides stream encryption utilities for binary streams:

• EncryptionStream
• DecryptionStream
• encryptStream
• decryptStream
• webCryptoStream

encryptStream() and decryptStream() are convenience helpers for piping an existing ReadableStream<Uint8Array> through the corresponding transform stream.

webCryptoStream(masterKey) is a higher-level helper for applications that manage stream keys with the Web Crypto API. It uses an AES-GCM master key to create encrypted 32-byte stream keys, then unwraps those keys before delegating to encryptStream() and decryptStream().

webCryptoStream example

import {
  readAllBytes,
  readableFromChunks,
  stringToBinary,
} from "@hsblabs/web-stream-extras";
import { webCryptoStream } from "@hsblabs/web-stream-extras/encryption";

const masterKey = await crypto.subtle.generateKey(
  { name: "AES-GCM", length: 256 },
  false,
  ["encrypt", "decrypt"],
);

const cryptoStream = webCryptoStream(masterKey);
const encryptedStreamKey = await cryptoStream.createStreamKey();
const plaintext = readableFromChunks(stringToBinary("secret payload"));

const encrypted = await cryptoStream.encrypt(encryptedStreamKey, plaintext);
const decrypted = await cryptoStream.decrypt(encryptedStreamKey, encrypted);
const result = await readAllBytes(decrypted);

console.log(new TextDecoder().decode(result)); // "secret payload"

Environment and Compatibility

• Node.js: >=22
• Browsers: works in modern browsers with Web Streams support
• Runtime APIs:
  • root utilities depend on the WHATWG Streams API
  • encryption depends on both the Web Streams API and Web Crypto

Notes

• encryption is intentionally a subpath export. The root package is not encryption-only.
• This package does not handle authentication, password-based key derivation, user management, or key storage.
• For encryption, you are expected to provide the raw encryption key (Uint8Array) yourself.
• webCryptoStream() is optional. It is a convenience wrapper when you already manage a separate AES-GCM master key and want encrypted per-stream keys as strings.