utf8_chunks

A TypeScript library for handling UTF-8 encoded strings, safely processing byte arrays containing invalid UTF-8 sequences.

Features

• Splits byte arrays into valid UTF-8 strings and invalid byte sequences
• Compliant with UTF-8 encoding specification (RFC 3629)
• Provides iterator interface for processing large data streams
• Fully type-safe

Installation

npm install utf8_chunks

Usage

import { Utf8Chunks, Utf8Chunk } from 'utf8_chunks';

// Create a byte array containing invalid UTF-8 sequences
const bytes = new Uint8Array([0x66, 0x6F, 0x6F, 0xF1, 0x80, 0x62, 0x61, 0x72]);

// Process the byte array using Utf8Chunks iterator
const chunks = new Utf8Chunks(bytes);

// Get the first chunk
const chunk = chunks.next().value;

// Get the valid UTF-8 string portion
console.log(chunk.valid); // Output: "foo"

// Get the invalid byte sequence
console.log(chunk.invalid); // Output: Uint8Array(2) [241, 128]

API Reference

Utf8Chunk Interface

interface Utf8Chunk {
    valid: string;      // Valid UTF-8 string
    invalid: Uint8Array; // Invalid byte sequence
}

Utf8Chunks Class

The Utf8Chunks class implements the Iterable<Utf8Chunk> interface for iterating over byte arrays.

class Utf8Chunks implements Iterable<Utf8Chunk> {
    constructor(source: Uint8Array);
    [Symbol.iterator](): Iterator<Utf8Chunk>;
}

Notes

• Invalid byte sequences have a maximum length of 3 bytes
• If invalid is empty, this is the last chunk in the string
• If invalid is non-empty, an unexpected byte was encountered or the input ended unexpectedly

Note

This library is inspired by Rust's std::str::Utf8Chunk implementation.

For more details about the original Rust implementation, see Rust's Utf8Chunk documentation.

License

MIT