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Mime Types Manager

import { mimetypesManager } from "/42/api/os/managers/mimetypesManager.js"
// Or
const mimetypesManager = sys42.mimetypes

The mimetypes manager maps file extensions and basenames to mimetypes, and to the apps that can open them.

The base mappings are populated from /42/lib/constant/FILE_TYPES.js.

Data model​

{ type: { subtype: { mimetype, extnames, basenames, apps, openers } } }.

After loading, the manager builds two lookup maps:

  • extnames - extension → mimetype entry.
  • basenames - basename → mimetype entry (for files with no extension).

Wildcards are supported. A type/* or */* entry applies to all matching files.

Methods​

  • normalize(mimetypes, options) - expands short entries (e.g. "json": ".json") into full type/subtype entries. Sync.
  • add(mimetypes, appName, options) - registers extnames and basenames, plus an app association. New extensions are recorded in openers as per-extension app openers. The first item will become the default opener.
  • setDefaultApp(mimetype, appName) - makes an app the default for a mimetype. Applies to wildcard subtypes too.
  • list(mimetype, options) - lists matching mimetype entries, optionally only those that have apps.
  • lookup(path) - returns the mimetype entry for a path plus the ordered list of apps that can open it. Per-extension openers defaults are moved to the front.
  • getExtnames(mimetype, options) - all extensions registered for a mimetype.
  • parse(mimetype) - parses a mimetype string into { type, subtype, suffix }.