mime-types-lite

A pnpm monorepo for the zero-dependency mime-types-lite TypeScript library and its interactive TanStack Start documentation site. The web app consumes the local package on every build, so API, examples, and documentation can be developed and verified together.

Open the live documentation · Read the package API · Install from npm

import { MIME, fromExtension, matchesMimeType } from "mime-types-lite";

MIME.JSON; // 'application/json'
fromExtension("reports/annual.pdf"); // 'application/pdf'
matchesMimeType("image/png", "image/*"); // true

What is included

Workspace	Purpose	Documentation
packages/mime-types-lite	Published ESM/CommonJS package with constants, lookup, normalization, validation, and matching helpers	Package README
apps/web	React 19 and TanStack Start documentation site with interactive examples	Web README

The dependency direction is one-way: apps/web depends on mime-types-lite through pnpm's workspace:* protocol; the library never depends on the application.

Quick start

Prerequisites:

• Node.js 20.19 or newer; .node-version selects Node.js 24
• pnpm 10.17.1

git clone https://github.com/montasim/mime-types-lite.git
cd mime-types-lite
pnpm install
pnpm dev

The root development command first builds the local package, then starts the web app at http://localhost:3000. No environment variables or external services are required.

Install and use the package

Consumers can install the published library without the web workspace:

pnpm add mime-types-lite

import {
    MIME,
    extensionsFor,
    fromExtension,
    isKnownMimeType,
    normalizeMimeType,
} from "mime-types-lite";

fromExtension("avatar.JPEG"); // 'image/jpeg'
extensionsFor(MIME.JPEG); // ['jpg', 'jpeg', 'jpe']
normalizeMimeType("Application/JSON; charset=utf-8"); // 'application/json'
isKnownMimeType("application/json; charset=utf-8"); // true

See the package README for the complete API, TypeScript types, standards references, compatibility aliases, and security guidance.

Workspace commands

Run these from the repository root:

Command	Purpose
pnpm dev	Build the package and start the web app on port 3000
pnpm build	Build the package followed by the production web app
pnpm build:package	Build the package's ESM, CommonJS, and declarations
pnpm build:web	Build the package and production web app
pnpm test	Run package runtime and type tests
pnpm test:types	Run package declaration and consumer type tests
pnpm check:package	Run complete package validation
pnpm check:web	Build the package, then verify the web app
pnpm check	Verify both workspaces
pnpm format	Format every workspace that defines a formatter
pnpm format:check	Check formatting across both workspaces

Repository layout

.
├── apps/
│   └── web/                       # TanStack Start site
├── packages/
│   └── mime-types-lite/           # Published npm package, tests, and package docs
├── .github/workflows/             # Workspace CI and npm publishing
├── netlify.toml                   # Monorepo-aware web deployment
└── pnpm-workspace.yaml            # Workspace discovery and dependency overrides

Quality and release workflow

CI installs the frozen pnpm lockfile and runs pnpm check on supported Node.js versions. This covers formatting, linting, TypeScript, package runtime and type tests, export and metadata validation, and the production web build. CI also inspects the npm tarball before changes merge.

Package publishing remains separate from ordinary pushes. Publishing a GitHub release tagged vX.Y.Z runs the release workflow, validates the package in packages/mime-types-lite, and publishes that workspace to npm with provenance. See the release guide and changelog.

Deployment

The root Netlify configuration runs pnpm build:web and publishes apps/web/dist/client. TanStack Start server output is handled by the official Netlify Vite integration. Local Netlify development runs on port 8888 and targets the Vite server on port 3000.

The public canonical URL is https://mime-types-lite.netlify.app. When deploying at another URL, update apps/web/src/config/site.ts, apps/web/vite.config.ts, and apps/web/public/robots.txt together.

Scope and security

mime-types-lite intentionally provides a small, curated set of media types rather than an exhaustive MIME database. A filename extension, browser File.type, or HTTP Content-Type value can be incorrect or attacker-controlled; these helpers do not inspect file bytes and must not be used as proof of file contents.

For untrusted uploads, inspect file signatures, enforce size limits, store files safely, and use hardened processing tools. Report vulnerabilities privately according to the security policy.

Contributing and support

Issues and focused pull requests are welcome in the GitHub repository. Data changes should cite an authoritative registry or specification, include relevant tests, and pass pnpm check. Read the contribution guide for the package workflow.

Optional support through SupportKori helps fund registry research, compatibility work, documentation, and publishing infrastructure.

Author and license

Created and maintained by Mohammad Montasim Al Mamun Shuvo. Licensed under the MIT License.