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@std/path

Overview Jump to heading

Utilities for working with OS-specific file paths.

Functions from this module will automatically switch to support the path style of the current OS, either windows for Microsoft Windows, or posix for every other operating system, eg. Linux, MacOS, BSD etc.

To use functions for a specific path style regardless of the current OS import the modules from the platform sub directory instead.

Basic Path Operations

import * as path from "@std/path";
import { assertEquals } from "@std/assert";

// Get components of a path
if (Deno.build.os === "windows") {
  assertEquals(path.basename("C:\\Users\\user\\file.txt"), "file.txt");
  assertEquals(path.dirname("C:\\Users\\user\\file.txt"), "C:\\Users\\user");
  assertEquals(path.extname("C:\\Users\\user\\file.txt"), ".txt");
} else {
  assertEquals(path.basename("/home/user/file.txt"), "file.txt");
  assertEquals(path.dirname("/home/user/file.txt"), "/home/user");
  assertEquals(path.extname("/home/user/file.txt"), ".txt");
}

// Join path segments
if (Deno.build.os === "windows") {
  assertEquals(path.join("C:\\", "Users", "docs", "file.txt"), "C:\\Users\\docs\\file.txt");
} else {
  assertEquals(path.join("/home", "user", "docs", "file.txt"), "/home/user/docs/file.txt");
}

// Normalize a path
if (Deno.build.os === "windows") {
  assertEquals(path.normalize("C:\\Users\\user\\..\\temp\\.\\file.txt"), "C:\\Users\\temp\\file.txt");
} else {
  assertEquals(path.normalize("/home/user/../temp/./file.txt"), "/home/temp/file.txt");
}

// Resolve absolute path
if (Deno.build.os === "windows") {
  const resolved = path.resolve("C:\\foo", "docs", "file.txt");
  assertEquals(resolved, "C:\\foo\\docs\\file.txt");
  assertEquals(path.isAbsolute(resolved), true);
} else {
  const resolved = path.resolve("/foo", "docs", "file.txt");
  assertEquals(resolved, "/foo/docs/file.txt");
  assertEquals(path.isAbsolute(resolved), true);
}

// Get relative path
if (Deno.build.os === "windows") {
  assertEquals(path.relative("C:\\Users", "C:\\Users\\docs\\file.txt"), "docs\\file.txt");
  assertEquals(path.relative("C:\\Users", "D:\\Programs"), "D:\\Programs");
} else {
  assertEquals(path.relative("/home/user", "/home/user/docs/file.txt"), "docs/file.txt");
  assertEquals(path.relative("/home/user", "/var/data"), "../../var/data");
}

Path Parsing and Formatting

import * as path from "@std/path";
import { assertEquals } from "@std/assert";

if (Deno.build.os === "windows") {
  const parsedWindows = path.parse("C:\\Users\\user\\file.txt");
  assertEquals(parsedWindows.root, "C:\\");
  assertEquals(parsedWindows.dir, "C:\\Users\\user");
  assertEquals(parsedWindows.base, "file.txt");
  assertEquals(parsedWindows.ext, ".txt");
  assertEquals(parsedWindows.name, "file");

  // Format path from components (Windows)
  assertEquals(
    path.format({ dir: "C:\\Users\\user", base: "file.txt" }),
    "C:\\Users\\user\\file.txt"
  );
} else {
  const parsedPosix = path.parse("/home/user/file.txt");
  assertEquals(parsedPosix.root, "/");
  assertEquals(parsedPosix.dir, "/home/user");
  assertEquals(parsedPosix.base, "file.txt");
  assertEquals(parsedPosix.ext, ".txt");
  assertEquals(parsedPosix.name, "file");

  // Format path from components (POSIX)
  assertEquals(
    path.format({ dir: "/home/user", base: "file.txt" }),
    "/home/user/file.txt"
  );
}

URL Conversion

import * as path from "@std/path";
import { assertEquals } from "@std/assert";

// Convert between file URLs and paths
if (Deno.build.os === "windows") {
  assertEquals(path.fromFileUrl("file:///C:/Users/user/file.txt"), "C:\\Users\\user\\file.txt");
  assertEquals(path.toFileUrl("C:\\Users\\user\\file.txt").href, "file:///C:/Users/user/file.txt");
} else {
  assertEquals(path.fromFileUrl("file:///home/user/file.txt"), "/home/user/file.txt");
  assertEquals(path.toFileUrl("/home/user/file.txt").href, "file:///home/user/file.txt");
}

Path Properties

import * as path from "@std/path";
import { assertEquals } from "@std/assert";

// Check if path is absolute
if (Deno.build.os === "windows") {
  assertEquals(path.isAbsolute("C:\\Users"), true);
  assertEquals(path.isAbsolute("\\\\Server\\share"), true);
  assertEquals(path.isAbsolute("C:relative\\path"), false);
  assertEquals(path.isAbsolute("..\\relative\\path"), false);
} else {
  assertEquals(path.isAbsolute("/home/user"), true);
  assertEquals(path.isAbsolute("./relative/path"), false);
  assertEquals(path.isAbsolute("../relative/path"), false);
}

// Convert to namespaced path (Windows-specific)
if (Deno.build.os === "windows") {
  assertEquals(path.toNamespacedPath("C:\\Users\\file.txt"), "\\\\?\\C:\\Users\\file.txt");
  assertEquals(path.toNamespacedPath("\\\\server\\share\\file.txt"), "\\\\?\\UNC\\server\\share\\file.txt");
} else {
  // On POSIX, toNamespacedPath returns the path unchanged
  assertEquals(path.toNamespacedPath("/home/user/file.txt"), "/home/user/file.txt");
}

Glob Pattern Utilities

import * as path from "@std/path";
import { assertEquals } from "@std/assert";

// Check if a string is a glob pattern
assertEquals(path.isGlob("*.txt"), true);

// Convert glob pattern to RegExp
const pattern = path.globToRegExp("*.txt");
assertEquals(pattern.test("file.txt"), true);

// Join multiple glob patterns
if (Deno.build.os === "windows") {
  assertEquals(path.joinGlobs(["src", "**\\*.ts"]), "src\\**\\*.ts");
} else {
  assertEquals(path.joinGlobs(["src", "**\/*.ts"]), "src/**\/*.ts");
}

// Normalize a glob pattern
if (Deno.build.os === "windows") {
  assertEquals(path.normalizeGlob("src\\..\\**\\*.ts"), "**\\*.ts");
} else {
  assertEquals(path.normalizeGlob("src/../**\/*.ts"), "**\/*.ts");
}

For POSIX-specific functions:

import { fromFileUrl } from "@std/path/posix/from-file-url";
import { assertEquals } from "@std/assert";

assertEquals(fromFileUrl("file:///home/foo"), "/home/foo");

For Windows-specific functions:

import { fromFileUrl } from "@std/path/windows/from-file-url";
import { assertEquals } from "@std/assert";

assertEquals(fromFileUrl("file:///home/foo"), "\\home\\foo");

Functions for working with URLs can be found in @std/path/posix.

Add to your project Jump to heading

deno add jsr:@std/path

See all symbols in @std/path on

When to use @std/path Jump to heading

Use it anywhere you build, normalize, or inspect file paths. It handles POSIX and Windows differences so your code stays portable.

Examples Jump to heading

import { basename, dirname, extname, join, resolve } from "@std/path";

const file = join("content", "posts", "hello.md");
console.log(dirname(file)); // content/posts
console.log(basename(file)); // hello.md
console.log(extname(file)); // .md
console.log(resolve(".", "assets")); // absolute path

Tips Jump to heading

  • Prefer join over string concatenation.
  • Use fromFileUrl/toFileUrl when moving between file URLs and paths.
  • For OS-specific logic, import from @std/path/posix or @std/path/windows.

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