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A tiny (2.8kB) and fast utility for getting a MIME type from an extension or filename

Features

Lightweight – 2.8kB gzip
Only includes standard mime types; all experimental and vendor-specific mimetypes removed.
Performant
All lookups are O(1) with minimal processing.
Comprehensive Dictionary
Generated from mime-db, which aggregates the IANA, NGINX, and Apache datasets.
Customizable
Exposes the mimes dictionary for easy additions or overrides.
Supports Native ESM and Deno
Ships with CommonJS and ESM support!

Install

$ npm install --save mrmime

Usage

import { lookup, mimes } from 'mrmime';

// Get a MIME type
// ---
lookup('txt'); //=> "text/plain"
lookup('.txt'); //=> "text/plain"
lookup('a.txt'); //=> "text/plain"

// Unknown extension
// ---
lookup('.xyz'); //=> undefined

// Add extension to dictionary
// ---
mimes['xyz'] = 'hello/world';
lookup('xyz'); //=> "hello/world"

API

lookup(input)

Returns: string or undefined

input

Type: string

The extension or filename to lookup.

Important:

Any input value is cast to string, lowercased, and trimmed.

If a filename or filepath is provided, only the extension will be used.

Benchmarks

Running on Node v16.8.0

Load times:
  mrmime     0.963ms
  mime/lite  3.281ms
  mime       6.751ms

Benchmark :: plain ("ext")
  mime          x 598,849 ops/sec ±0.28% (94 runs sampled)
  mime/lite     x 536,643 ops/sec ±0.11% (97 runs sampled)
  mrmime        x 835,885 ops/sec ±0.20% (97 runs sampled)

Benchmark :: leading (".ext")
  mime          x 368,656 ops/sec ±0.19% (99 runs sampled)
  mime/lite     x 368,318 ops/sec ±0.13% (97 runs sampled)
  mrmime        x 533,643 ops/sec ±0.10% (96 runs sampled)

Benchmark :: filename ("file.ext")
  mime          x 326,907 ops/sec ±0.17% (95 runs sampled)
  mime/lite     x 327,479 ops/sec ±0.12% (98 runs sampled)
  mrmime        x 512,823 ops/sec ±0.12% (99 runs sampled)

Credits

Of course, a thank-you to mime serving the community all these years & for being a all-encompassing MIME type library. I've only ever needed lookup/getType functionality – and now ESM support – so mrmime can only ever support 1/3 of what mime offers, at best.

This would not be possible without the team behind mime-db, who have painstakingly maintained an amazing database for 7+ years.

Artwork created by mintinol, which I found here.

Finally, thanks to Tim Branyen for donating the package name :)

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