chore: docs and api changes

README.md

@@ -54,21 +54,18 @@ here's a brief rundown ...
 truth" for MIME type information. It is a dataset (JSON file), not an API, with mime type definitions pulled from a variety of authoritative sources.
 
 [`mime-types`](https://github.com/jshttp/mime-types) is a thin
-wrapper around mime-db that provides an API drop-in compatible(ish) with `mime @ < v1.3.6` API.
+wrapper around mime-db that provides an API that is mostly-compatible with `mime @ < v1.3.6`.
 
-`mime` (this project) is similar to `mime-types`, but with the following enhancements:
+`mime` (this project) is like `mime-types`, but with the following enhancements:
 
 - Resolves type conflicts (See [mime-score](https://github.com/broofa/mime-score) for details)
-- Compact footprint. (2KB vs 18KB)
-- Native TS support
+- Smaller (`mime` is 2-8KB, `mime-types` is 18KB)
+- Zero dependencies
+- Built-in TS support
 
 ## Mime API
 
-Both `require('mime')` and `require('mime/lite')` return instances of the MIME
-class, documented below.
-
-Note: Inputs to this API are case-insensitive. Outputs (returned values) will
-be lowercase.
+Both `require('mime')` and `require('mime/lite')` return instances of the `Mime` class, documented below.
 
 ### new Mime(typeMap, ... more maps)
 
@@ -125,6 +122,12 @@ Content-Type headers) are ignored.
 mime.getExtension('text/plain');               // ⇨ 'txt'
 mime.getExtension('application/json');         // ⇨ 'json'
 mime.getExtension('text/html; charset=utf8');  // ⇨ 'html'
+### mime.getAllExtensions(type)
+
+Get all extensions for the given mime type.
+
+```javascript --run default
+mime.getAllExtensions('image/jpeg'); // ⇨ [ 'jpeg', 'jpg', 'jpe' ]
 ```
 
 ### mime.define(typeMap[, force = false])

docs/README_js.md

@@ -54,13 +54,14 @@ here's a brief rundown ...
 truth" for MIME type information. It is a dataset (JSON file), not an API, with mime type definitions pulled from a variety of authoritative sources.
 
 [`mime-types`](https://github.com/jshttp/mime-types) is a thin
-wrapper around mime-db that provides an API drop-in compatible(ish) with `mime @ < v1.3.6` API.
+wrapper around mime-db that provides an API that is mostly-compatible with `mime @ < v1.3.6`.
 
-`mime` (this project) is similar to `mime-types`, but with the following enhancements:
+`mime` (this project) is like `mime-types`, but with the following enhancements:
 
 - Resolves type conflicts (See [mime-score](https://github.com/broofa/mime-score) for details)
-- Compact footprint (2-8KB .vs. 18KB)
-- Native TS support
+- Smaller (`mime` is 2-8KB, `mime-types` is 18KB)
+- Zero dependencies
+- Built-in TS support
 
 ## Mime API
 
@@ -123,6 +124,14 @@ mime.getExtension('application/json'); // RESULT
 mime.getExtension('text/html; charset=utf8'); // RESULT
 ```
 
+### mime.getAllExtensions(type)
+
+Get all extensions for the given mime type.
+
+```javascript --run default
+mime.getAllExtensions('text/plain'); // RESULT
+```
+
 ### mime.define(typeMap[, force = false])
 
 Define [more] type mappings.

src/Mime.ts

@@ -67,7 +67,7 @@ export default class Mime {
   }
 
   /**
-   * Lookup a mime type based on extension
+   * Get mime type associated with an extension
    */
   getType(path: string) {
     if (typeof path !== 'string') return null;
@@ -88,7 +88,7 @@ export default class Mime {
   }
 
   /**
-   * Return file extension associated with a mime type
+   * Get default file extension associated with a mime type
    */
   getExtension(type: string) {
     if (typeof type !== 'string') return null;
@@ -101,16 +101,17 @@ export default class Mime {
     );
   }
 
+  /**
+   * Get all file extensions associated with a mime type
+   */
   getAllExtensions(type: string) {
-    if (typeof type !== 'string') return [];
-
-    const extensions = this.#typeToExtensions.get(type.toLowerCase());
+    if (typeof type !== 'string') return null;
 
-    return extensions ? [...extensions] : [];
+    return this.#typeToExtensions.get(type.toLowerCase()) ?? null;
   }
 
   //
-  // INTERNAL USE ONLY
+  // Private API, for internal use only.  These APIs may change at any time
   //
 
   _freeze() {
@@ -121,7 +122,7 @@ export default class Mime {
     Object.freeze(this);
 
     for (const extensions of this.#typeToExtensions.values()) {
-      Object.freeze([...extensions]);
+      Object.freeze(extensions);
     }
 
     return this;

test/mime.test.js

@@ -151,7 +151,11 @@ describe('class Mime', (t) => {
 
 it('getAllExtensions()', () => {
   const mime = new Mime({ 'text/a': ['a', 'b'] }, { 'text/a': ['b', 'c'] });
-  assert.deepEqual(mime.getAllExtensions('text/a').sort(), ['a', 'b', 'c']);
+  assert.deepEqual([...mime.getAllExtensions('text/a')].sort(), [
+    'a',
+    'b',
+    'c',
+  ]);
 });
 
 describe('DB', () => {