All files / path / windows / from_file_url.ts

// Copyright 2018-2025 the Deno authors. MIT license.
// This module is browser compatible.

import { assertArg } from "../_common/from_file_url.ts";

/**
 * Converts a file URL to a path string.
 *
 * @example Usage
 * ```ts
 * import { fromFileUrl } from "@std/path/windows/from-file-url";
 * import { assertEquals } from "@std/assert";
 *
 * assertEquals(fromFileUrl("file:///home/foo"), "\\home\\foo");
 * assertEquals(fromFileUrl("file:///C:/Users/foo"), "C:\\Users\\foo");
 * assertEquals(fromFileUrl("file://localhost/home/foo"), "\\home\\foo");
 * ```
 *
 * @param url The file URL to convert.
 * @returns The path string.
 */
export function fromFileUrl(url: URL | string): string {
  url = assertArg(url);
  let path = decodeURIComponent(
    url.pathname.replace(/\//g, "\\").replace(/%(?![0-9A-Fa-f]{2})/g, "%25"),
  ).replace(/^\\*([A-Za-z]:)(\\|$)/, "$1\\");
  if (url.hostname !== "") {
    // Note: The `URL` implementation guarantees that the drive letter and
    // hostname are mutually exclusive. Otherwise it would not have been valid
    // to append the hostname and path like this.
    path = `\\\\${url.hostname}${path}`;
  }
  return path;
}