whatwg-url-minimum

whatwg-url-minimum is a compact WHATWG URL Standard implementation for JavaScript runtimes that need URL and URLSearchParams without the size and runtime assumptions of larger URL packages.

It is derived from jsdom/whatwg-url, ported to TypeScript, and optimized for small bundles and React Native / Expo-style environments.

This package is primarily intended for Expo and React Native projects that need a standards-oriented URL implementation with predictable behavior across JavaScript engines, while keeping application bundles small.

Implementation

The goal of whatwg-url-minimum is to keep the observable URL and URLSearchParams behavior close to the platform standard while reducing implementation size and avoiding runtime features that are not consistently available outside browsers and Node.js.

The implementation focuses on:

• Compact parser code: A small TypeScript URL parser with special-scheme, file URL, host, path, query, and fragment handling.
• Small IDNA/TR46 support: Domain normalization includes UTS #46 mapping, punycode encoding, joiner validation, and selected validity checks without shipping a full Unicode processing stack.
• Fast URLSearchParams operations: Query parsing, mutation, sorting, and serialization are optimized for repeated use.

Quick Start

import { URL, URLSearchParams } from 'whatwg-url-minimum';

const url = new URL('https://Bücher.de/search?q=hello world');

url.hostname; // "xn--bcher-kva.de"
url.searchParams.append('page', '1');
url.href; // "https://xn--bcher-kva.de/search?q=hello%20world&page=1"

const params = new URLSearchParams('a=1&a=2');
params.getAll('a'); // ["1", "2"]

API Reference

class URL

URL follows the standard constructor and static helper shape:

new URL(input: string, base?: string);
URL.canParse(input: string, base?: string): boolean;
URL.parse(input: string, base?: string): URL | null;

Supported instance properties and methods include the standard URL surface:

• href
• origin
• protocol
• username
• password
• host
• hostname
• port
• pathname
• search
• searchParams
• hash
• toString()
• toJSON()

class URLSearchParams

URLSearchParams supports the standard constructor forms and mutation/query methods:

new URLSearchParams();
new URLSearchParams('a=1&b=2');
new URLSearchParams([['a', '1']]);
new URLSearchParams({ a: '1' });

Supported methods and properties include:

• append(name, value)
• delete(name, value?)
• get(name)
• getAll(name)
• has(name, value?)
• set(name, value)
• sort()
• forEach(callback, thisArg?)
• keys()
• values()
• entries()
• size
• toString()

Conformance

The test suite runs downloaded Web Platform Tests for URL parsing, URL setters, URLSearchParams, static helpers, and WebIDL behavior. It also includes local coverage for WPT resources that cannot be run directly in Vitest, such as toascii.window.js and percent-encoding.window.js.

Additional local tests compare IDNA/TR46 behavior against whatwg-url for the active toascii.json cases and seeded mixed-script domain cases.

Current known divergence:

• Full RFC 5893 CheckBidi validation is not implemented. The implementation contains a small mixed Latin/RTL rejection that covers the active URL WPT toascii cases without adding generated Bidi_Class tables.
• Revalidation of pre-existing xn-- labels after UTS #46 mapping is intentionally omitted. This avoids shipping a punycode decoder solely for obsolete/removed IDNA validity coverage.
• IdnaTestV2-removed.any.js is intentionally omitted because it contains obsolete/deprecated IDNA cases outside this package's active conformance target.