Magic Types

简体中文

Get the MIME of the data by parsing the Magic Number in the file header, supporting most common file types.

Features

• Supports browsers and Nodejs
• Efficient and no need for complete data, can infer MIME directly from url/Base64/ArrayBuffer data
• Simple and small (5kb), no dependencies

Usage

npm module

npm i magic-types

import { fetchMime, base64Mime, arraybufferMime } from 'magic-types'

// use fetch request to read header data speculation -> image/png
console.log(await fetchMime("https://en.wikipedia.org/static/images/icons/wikipedia.png")) // -> image/png

// using base64 header data speculation -> image/png
console.log(base64Mime("iVBORw0KGgoAAAANSUhEUgAAAMgAAAC3CAMAAABg8uG4AAACNFBMVEVMaXGHh4jc3N6bm5yNjo6Vlpjh4eOnqKuysrPW19mwsbOtra5vb2 /Fxsd4eHiBg4SY"))

// use ArrayBuffer header data speculation -> image/png
const res = await fetch("https://en.wikipedia.org/static/images/icons/wikipedia.png")
const buffer = await res.arrayBuffer()
console.log(arraybufferMime(buffer))

From CDN

<script src="https://unpkg.com/magic-types/dist/magic-types.umd.js"></script>
<!-- or https://www.jsdelivr.com/npm/magic-types/dist/umd/magic-types.umd.js -->

Document

base64Mime(base64String: string): string

Use base64 headers to infer the document MIME type

fetchMime(url: string, requestInit: RequestInit): Promise

For fetch requests, it is recommended to use Content-Type as the MIME type in preference to using this method blindly.

arraybufferMime(arraybuffer: ArrayBuffer): string

Using ArrayBuffer header data speculation

License

MIT