#  [](https://www.npmjs.com/package/@thi.ng/mime)  [](https://mastodon.thi.ng/@toxi) > [!NOTE] > This is one of 216 standalone projects. LLM-free, human-made and > cared for software, maintained as part of the > [@thi.ng/umbrella](https://codeberg.org/thi.ng/umbrella/) ecosystem and > anti-framework. > > 🚀 Please help me to work full-time on these projects by [sponsoring > me](https://codeberg.org/thi.ng/umbrella/src/branch/develop/CONTRIBUTING.md#donations). > Thank you! ❤️ - [About](#about) - [Status](#status) - [Related packages](#related-packages) - [Installation](#installation) - [Dependencies](#dependencies) - [Usage examples](#usage-examples) - [API](#api) - [Determining MIME type from file extension](#determining-mime-type-from-file-extension) - [Determining file extension from MIME type](#determining-file-extension-from-mime-type) - [Checking if MIME type is compressible](#checking-if-mime-type-is-compressible) - [Conversion from mime-db](#conversion-from-mime-db) - [Authors](#authors) - [License](#license) ## About 650+ file extension to MIME type mappings, based on mime-db. All MIME type mappings are based on [mime-db](https://github.com/jshttp/mime-db) (2023-02-17). For filesize reasons only [a small selected number](https://codeberg.org/thi.ng/umbrella/src/branch/develop/packages/mime/tools/convert.ts#L7) of [vendor MIME types](https://www.rfc-editor.org/rfc/rfc4288#section-3.2) (aka `*/vnd.*`) are included. Most of the omitted ones are fairly obscure anyway, so likely not problematic... Additionally, this package defines some MIME types not included in the original DB, as well as some preference overrides. ## Status **STABLE** - used in production [Search or submit any issues for this package](https://codeberg.org/thi.ng/umbrella/issues?q=%5Bmime%5D) ## Related packages - [@thi.ng/dl-asset](https://codeberg.org/thi.ng/umbrella/src/branch/develop/packages/dl-asset) - Canvas, video recording & file asset download helpers for web apps ## Installation ```bash yarn add @thi.ng/mime ``` ESM import: ```ts import * as mime from "@thi.ng/mime"; ``` Browser ESM import: ```html ``` [JSDelivr documentation](https://www.jsdelivr.com/) For Node.js REPL: ```js const mime = await import("@thi.ng/mime"); ``` Package sizes (brotli'd, pre-treeshake): ESM: 4.83 KB ## Dependencies None ## Usage examples Eight projects in this repo's [/examples](https://codeberg.org/thi.ng/umbrella/src/branch/develop/examples) directory are using this package: | Screenshot | Description | Live demo | Source | |:---------------------------------------------------------------------------------------------------------------------------|:----------------------------------------------------------------------------|:----------------------------------------------------------|:-----------------------------------------------------------------------------------------------| | | Interactive image processing (adaptive threshold) | [Demo](https://demo.thi.ng/umbrella/adaptive-threshold/) | [Source](https://codeberg.org/thi.ng/umbrella/src/branch/develop/examples/adaptive-threshold) | | | Interactive & reactive image blurhash generator | [Demo](https://demo.thi.ng/umbrella/blurhash/) | [Source](https://codeberg.org/thi.ng/umbrella/src/branch/develop/examples/blurhash) | | | Color palette generation via dominant color extraction from uploaded images | [Demo](https://demo.thi.ng/umbrella/dominant-colors/) | [Source](https://codeberg.org/thi.ng/umbrella/src/branch/develop/examples/dominant-colors) | | | Interactive pixel sorting tool using thi.ng/color & thi.ng/pixel | [Demo](https://demo.thi.ng/umbrella/pixel-sorting/) | [Source](https://codeberg.org/thi.ng/umbrella/src/branch/develop/examples/pixel-sorting) | | | RGB waveform image analysis | [Demo](https://demo.thi.ng/umbrella/pixel-waveform/) | [Source](https://codeberg.org/thi.ng/umbrella/src/branch/develop/examples/pixel-waveform) | | | Basic usage of the declarative rdom-forms generator | [Demo](https://demo.thi.ng/umbrella/rdom-formgen/) | [Source](https://codeberg.org/thi.ng/umbrella/src/branch/develop/examples/rdom-formgen) | | | Multi-layer vectorization & dithering of bitmap images | [Demo](https://demo.thi.ng/umbrella/trace-bitmap/) | [Source](https://codeberg.org/thi.ng/umbrella/src/branch/develop/examples/trace-bitmap) | | | rdom & WebGL-based image channel editor | [Demo](https://demo.thi.ng/umbrella/webgl-channel-mixer/) | [Source](https://codeberg.org/thi.ng/umbrella/src/branch/develop/examples/webgl-channel-mixer) | ## API [Generated API docs](https://docs.thi.ng/umbrella/mime/) This package exposes a `MIME_TYPES` object which provides mappings from file extensions to MIME types. For each extension one or more MIME types are provided, with the default type always in first position. ```ts import { MIME_TYPES } from "@thi.ng/mime"; MIME_TYPES.mp3 // [ 'audio/mpeg', 'audio/mp3' ] MIME_TYPES.jpg // [ 'image/jpeg' ] MIME_TYPES.jpeg // [ 'image/jpeg' ] ``` ### Determining MIME type from file extension To simplify lookup and support a fallback type, the package has `preferredType()` function: ```ts import { preferredType } from "@thi.ng/mime"; preferredType("mp3") // "audio/mpeg" // unknown file extension w/ default fallback type preferredType("foo") // "application/octet-stream" // unknown file extension w/ given fallback type preferredType("foo", "text/plain") // "text/plain" ``` ### Determining file extension from MIME type Reverse lookups are possible too, using `preferredExtension()` (also supports fallback): ```ts import { preferredExtension } from "@thi.ng/mime"; preferredExtension("image/svg+xml"); // "svg" preferredExtension("image/foo"); // "bin" (default fallback) preferredExtension("image/foo", "dat"); // "dat" (custom fallback) ``` ### Checking if MIME type is compressible The original [mime-db](https://github.com/jshttp/mime-db) includes information if a MIME type is compressible (gzippable). This information can be obtained via `isCompressible()`. Note: Some of these decisions seem to be questionable/wrong (e.g. many plain text formats are marked as false), but taken here as provided... ```ts import { isCompressible } from "@thi.ng/mime"; isCompressible("text/javascript"); // true isCompressible(preferredType("mp4")) // false ``` ## Conversion from mime-db 1. Download the [latest version of mime-db's JSON index](https://raw.githubusercontent.com/jshttp/mime-db/master/db.json) and save it to `[packages/mime/]tools/mime-db.json` 2. Run the following command to build an up-to-date index (assumes the umbrella repo has been pre-built already). Output will always be be written to `src/generated.ts`. ```bash # from the thi.ng/umbrella repo root (cd packages/mime && yarn tool:convert) ``` Additional configuration options are available in the [`tools/convert.ts`](https://codeberg.org/thi.ng/umbrella/src/branch/develop/packages/mime/tools/convert.ts) script. ## Authors - [Karsten Schmidt](https://thi.ng) If this project contributes to an academic publication, please cite it as: ```bibtex @misc{thing-mime, title = "@thi.ng/mime", author = "Karsten Schmidt", note = "https://thi.ng/mime", year = 2020 } ``` ## License © 2020 - 2026 Karsten Schmidt // Apache License 2.0