All files / path / windows / basename.ts

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

import {
  assertArgs,
  lastPathSegment,
  stripSuffix,
} from "../_common/basename.ts";
import { CHAR_COLON } from "../_common/constants.ts";
import { stripTrailingSeparators } from "../_common/strip_trailing_separators.ts";
import { isPathSeparator, isWindowsDeviceRoot } from "./_util.ts";

/**
 * Return the last portion of a `path`.
 * Trailing directory separators are ignored, and optional suffix is removed.
 *
 * @example Usage
 * ```ts
 * import { basename } from "@std/path/windows/basename";
 * import { assertEquals } from "@std/assert";
 *
 * assertEquals(basename("C:\\user\\Documents\\"), "Documents");
 * assertEquals(basename("C:\\user\\Documents\\image.png"), "image.png");
 * assertEquals(basename("C:\\user\\Documents\\image.png", ".png"), "image");
 * ```
 *
 * Note: If you are working with file URLs,
 * use the new version of `basename` from `@std/path/windows/unstable-basename`.
 *
 * @param path The path to extract the name from.
 * @param suffix The suffix to remove from extracted name.
 * @returns The extracted name.
 */
export function basename(path: string, suffix = ""): string {
  assertArgs(path, suffix);

  // Check for a drive letter prefix so as not to mistake the following
  // path separator as an extra separator at the end of the path that can be
  // disregarded
  let start = 0;
  if (path.length >= 2) {
    const drive = path.charCodeAt(0);
    if (isWindowsDeviceRoot(drive)) {
      if (path.charCodeAt(1) === CHAR_COLON) start = 2;
    }
  }

  const lastSegment = lastPathSegment(path, isPathSeparator, start);
  const strippedSegment = stripTrailingSeparators(lastSegment, isPathSeparator);
  return suffix ? stripSuffix(strippedSegment, suffix) : strippedSegment;
}