Function typeByExtension

typeByExtension(extension): string | undefined
Returns the media type associated with the file extension, or undefined if no media type is found.

Values are normalized to lower case and matched irrespective of a leading ..
Parameters
- extension: string
  The file extension to get the media type for.
Returns string | undefined
The media type associated with the file extension, or undefined if no media type is found.
Example: Usage
```
import { typeByExtension } from "@std/media-types/type-by-extension";
import { assertEquals } from "@std/assert";

assertEquals(typeByExtension("js"), "text/javascript");
assertEquals(typeByExtension(".HTML"), "text/html");
assertEquals(typeByExtension("foo"), undefined);
assertEquals(typeByExtension("file.json"), undefined);
```
- Defined in media_types/type_by_extension.ts:29