Registry / http-networking / react-native-mime-types

react-native-mime-types

library2.5.0jsnpmunverified

react-native-mime-types is a focused utility for identifying and managing MIME (Multipurpose Internet Mail Extensions) types within React Native applications. It provides core functions like `lookup` to determine content types from file extensions or paths, `contentType` to construct full Content-Type headers, and `extension` to find the default file extension for a given MIME type. Unlike the general-purpose `node-mime` library, this package explicitly returns `false` for unknown types instead of providing naive fallbacks, requiring developers to implement their own fallback logic. It operates purely functionally, eschewing `new Mime()` constructors or a `.define()` API for adding custom types; all type definitions are sourced from the comprehensive `mime-db` project. The current stable version is 2.5.0, and it receives updates as needed, often reflecting changes in `mime-db`. Its primary differentiator is its simplicity and explicit behavior regarding unknown types, making it predictable for React Native environments.

http-networking serialization

npm install react-native-mime-types

github ↗package ↗

INSTALL

IMPORT

SIG · REACT-NATIVE-MIME-

react-native-mime-types

http-networkingjavascriptv2.5.0

Install

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Import

—

Disk

—

Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

build_error

glibc

node 18–226 runs

build_error

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

mime

✓ import * as mime from 'react-native-mime-types';

✗ import mime from 'react-native-mime-types';

The library exports a namespace object, not a default export. Access functions via `mime.lookup`, `mime.contentType`, etc.

mime

✓ const mime = require('react-native-mime-types');

✗ const { lookup, contentType } = require('react-native-mime-types');

For CommonJS environments, the entire API is exposed as properties of the `mime` object.

mime.lookup

✓ import * as mime from 'react-native-mime-types'; mime.lookup('file.json');

✗ import { lookup } from 'react-native-mime-types'; lookup('file.json');

Functions like `lookup` and `contentType` are properties of the main `mime` object and are not directly named exports.

Demonstrates common MIME type lookups by extension or path, content-type header generation, extension retrieval, and direct map access, including handling unrecognized types.

import * as mime from 'react-native-mime-types'; console.log('--- MIME Type Lookups ---'); console.log('JSON file type:', mime.lookup('json')); // 'application/json' console.log('Markdown file type:', mime.lookup('.md')); // 'text/x-markdown' console.log('HTML file type:', mime.lookup('file.html')); // 'text/html' console.log('JavaScript file type:', mime.lookup('folder/file.js')); // 'application/javascript' console.log('Unrecognized file type (should be false):', mime.lookup('cats')); // false console.log('\n--- Content-Type Header Creation ---'); console.log('Markdown content type header:', mime.contentType('markdown')); // 'text/x-markdown; charset=utf-8' console.log('JSON content type header:', mime.contentType('file.json')); // 'application/json; charset=utf-8' console.log('\n--- Extension Lookup ---'); console.log('Extension for octet-stream:', mime.extension('application/octet-stream')); // 'bin' console.log('\n--- Direct Maps ---'); console.log('Type for .txt:', mime.types['txt']); // 'text/plain' console.log('Extensions for text/html:', mime.extensions['text/html']); // ['html', 'htm']

Debug

Known issues

gotchaUnlike some MIME libraries (e.g., node-mime), `react-native-mime-types` returns `false` for unrecognized or invalid input, rather than providing a default fallback like 'application/octet-stream'. You must explicitly handle `false` returns.

fix

Implement custom fallback logic: `const type = mime.lookup(path) || 'application/octet-stream';`

affects: >=2.0.0

gotchaThe library does not expose a constructor; do not attempt to use `new mime()` or `new Mime()` patterns. It's a purely functional API.

fix

All functions are accessed directly from the imported `mime` object (e.g., `mime.lookup()`).

affects: >=2.0.0

gotcha`react-native-mime-types` does not provide a `.define()` method to add custom MIME types at runtime. All type definitions are based on `mime-db`.

fix

To add new or custom MIME types, contribute them to the `mime-db` project, or manage a separate, custom mapping within your application code.

affects: >=2.0.0

Errors

Common errors & fixes

TypeError: mime.define is not a function

Attempting to use a `.define()` method to add custom MIME types, which this library does not support.

fix

This library does not allow runtime definition of MIME types. Rely on `mime-db` for definitions or manage custom types manually.

TypeError: Cannot read properties of undefined (reading 'lookup')

The `mime` object was not imported correctly, or an attempt was made to destructure named exports that do not exist.

fix

Ensure the library is imported as a namespace object (ESM: `import * as mime from 'react-native-mime-types';`) or the full module object (CommonJS: `const mime = require('react-native-mime-types');`). All functions are properties of the `mime` object.

Upgrade

Version history

2.5.0latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

4 hits · last 30 days

node

Resources

githubhttps://github.com/Liroo/react-native-mime-types ↗

packagehttps://www.npmjs.com/package/react-native-mime-types ↗