@prexjs/utils

Core utility functions for Prex and Express applications including ETag generation, trust proxy compilation, query parsing, and MIME normalization.

@prexjs/utils provides shared helper functions and internal compilation utilities used across @prexjs/prex, @prexjs/application, @prexjs/request, and @prexjs/response.

Features

• ETag Generators: Strong and weak ETag hashing (etag, wetag, compileETag).
• Proxy Trust Compilation: Compiles IP addresses, subnets, hop counts, or trust predicates using @prexjs/proxy-address.
• Query String Compilers: Supports simple (node:querystring) and extended (qs) query string parsers.
• Header & MIME Helpers: Normalizes content types, inspects media type accept parameters, and sets character encodings.
• HTTP Methods List: Complete list of supported HTTP methods recognized by Node.js.

Installation

Install using your preferred package manager:

# npm
npm install @prexjs/utils

# pnpm
pnpm add @prexjs/utils

# Yarn
yarn add @prexjs/utils

# Bun
bun add @prexjs/utils

Quick start

import {
  compileTrust,
  compileQueryParser,
  compileETag,
  setCharset,
} from '@prexjs/utils';

// Compile proxy trust helper
const trust = compileTrust('loopback, 10.0.0.0/8');
console.log(trust('127.0.0.1', 0)); // true

// Compile query parser
const parseQuery = compileQueryParser('extended');
console.log(parseQuery('user[name]=Alice&user[role]=admin'));

// Set charset on Content-Type
const contentType = setCharset('text/html', 'utf-8');
console.log(contentType); // 'text/html; charset=utf-8'

API

compileTrust(val)

Compiles a proxy trust setting into a predicate function (addr: string, i: number) => boolean. Accepts booleans, numbers (hop count), IP addresses, CIDR ranges, or custom functions.

compileETag(val)

Returns an ETag generator function. Accepts 'strong', 'weak', booleans, or custom functions.

compileQueryParser(val)

Returns a query string parsing function. Accepts 'simple', 'extended', booleans, or custom functions.

setCharset(type, charset)

Appends or replaces the charset parameter on an existing MIME type string.

normalizeType(type) / normalizeTypes(types)

Normalizes shorthand extensions (e.g. 'json') to full MIME type descriptors (e.g. 'application/json').

Compatibility

• Node.js >= 18.0.0
• Supports both ESM and CommonJS
• TypeScript 5.0+

Related Packages

• @prexjs/prex: The core Prex framework.
• @prexjs/etag: Low-level ETag creation.
• @prexjs/proxy-address: Proxy address resolution.

License

MIT