All files / path / posix / basename.ts

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

import {
  assertArgs,
  lastPathSegment,
  stripSuffix,
} from "../_common/basename.ts";
import { stripTrailingSeparators } from "../_common/strip_trailing_separators.ts";
import { isPosixPathSeparator } 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/posix/basename";
 * import { assertEquals } from "@std/assert";
 *
 * assertEquals(basename("/home/user/Documents/"), "Documents");
 * assertEquals(basename("/home/user/Documents/image.png"), "image.png");
 * assertEquals(basename("/home/user/Documents/image.png", ".png"), "image");
 * ```
 *
 * @example Working with URLs
 *
 * Note: This function doesn't automatically strip hash and query parts from
 * URLs. If your URL contains a hash or query, remove them before passing the
 * URL to the function. This can be done by passing the URL to `new URL(url)`,
 * and setting the `hash` and `search` properties to empty strings.
 *
 * ```ts
 * import { basename } from "@std/path/posix/basename";
 * import { assertEquals } from "@std/assert";
 *
 * assertEquals(basename("https://deno.land/std/path/mod.ts"), "mod.ts");
 * assertEquals(basename("https://deno.land/std/path/mod.ts", ".ts"), "mod");
 * assertEquals(basename("https://deno.land/std/path/mod.ts?a=b"), "mod.ts?a=b");
 * assertEquals(basename("https://deno.land/std/path/mod.ts#header"), "mod.ts#header");
 * ```
 *
 * Note: If you are working with file URLs,
 * use the new version of `basename` from `@std/path/posix/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);

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