// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
// This module is browser compatible.

import { parseMediaType } from "./parse_media_type.ts";
import { extensions } from "./_util.ts";

export { extensions };

/**
 * Returns the extensions known to be associated with the media type `type`.
 * The returned extensions will each begin with a leading dot, as in `.html`.
 *
 * When `type` has no associated extensions, the function returns `undefined`.
 *
 * Extensions are returned without a leading `.`.
 *
 * @example
 * ```ts
 * import { extensionsByType } from "@std/media-types/extensions_by_type";
 *
 * extensionsByType("application/json"); // ["json", "map"]
 * extensionsByType("text/html; charset=UTF-8"); // ["html", "htm", "shtml"]
 * extensionsByType("application/foo"); // undefined
 * ```
 */
export function extensionsByType(type: string): string[] | undefined {
  try {
    const [mediaType] = parseMediaType(type);
    return extensions.get(mediaType);
  } catch {
    // just swallow errors, returning undefined
  }
}