

[!NOTE]
This is one of 206 standalone projects, maintained as part
of the @thi.ng/umbrella monorepo
and anti-framework.
š Please help me to work full-time on these projects by sponsoring me on
GitHub. Thank you! ā¤ļø
About
650+ file extension to MIME type mappings, based on mime-db.
All MIME type mappings are based on mime-db
(2023-02-17). For filesize reasons only a small selected
number
of vendor MIME types (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
Related packages
- @thi.ng/dl-asset - Canvas, video recording & file asset download helpers for web apps
Installation
yarn add @thi.ng/mime
ESM import:
import * as mime from "@thi.ng/mime";
Browser ESM import:
<script type="module" src="https://esm.run/@thi.ng/mime"></script>
JSDelivr documentation
For Node.js REPL:
const mime = await import("@thi.ng/mime");
Package sizes (brotli'd, pre-treeshake): ESM: 4.82 KB
Dependencies
None
Usage examples
Eight projects in this repo's
/examples
directory are using this package:
 | Interactive image processing (adaptive threshold) | Demo | Source |
 | Interactive & reactive image blurhash generator | Demo | Source |
 | Color palette generation via dominant color extraction from uploaded images | Demo | Source |
 | Interactive pixel sorting tool using thi.ng/color & thi.ng/pixel | Demo | Source |
 | RGB waveform image analysis | Demo | Source |
 | Basic usage of the declarative rdom-forms generator | Demo | Source |
 | Multi-layer vectorization & dithering of bitmap images | Demo | Source |
 | rdom & WebGL-based image channel editor | Demo | Source |
API
Generated API docs
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.
import { MIME_TYPES } from "@thi.ng/mime";
MIME_TYPES.mp3
MIME_TYPES.jpg
MIME_TYPES.jpeg
Determining MIME type from file extension
To simplify lookup and support a fallback type, the package has
preferredType()
function:
import { preferredType } from "@thi.ng/mime";
preferredType("mp3")
preferredType("foo")
preferredType("foo", "text/plain")
Determining file extension from MIME type
Reverse lookups are possible too, using preferredExtension()
(also supports fallback):
import { preferredExtension } from "@thi.ng/mime";
preferredExtension("image/svg+xml");
preferredExtension("image/foo");
preferredExtension("image/foo", "dat");
Checking if MIME type is compressible
The original 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...
import { isCompressible } from "@thi.ng/mime";
isCompressible("text/javascript");
isCompressible(preferredType("mp4"))
Conversion from mime-db
- Download the latest version of mime-db's JSON
index and
save it to
[packages/mime/]tools/mime-db.json
- 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
.
(cd packages/mime && yarn tool:convert)
Additional configuration options are available in the
tools/convert.ts
script.
Authors
If this project contributes to an academic publication, please cite it as:
@misc{thing-mime,
title = "@thi.ng/mime",
author = "Karsten Schmidt",
note = "https://thi.ng/mime",
year = 2020
}
License
Ā© 2020 - 2025 Karsten Schmidt // Apache License 2.0