Path operations

Many applications need to manipulate file paths in one way or another. The Deno Standard Library provides simple utilities for this.

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First we will import the module from the Deno Standard Library

import * as path from "jsr:@std/path";
import * as posix from "jsr:@std/path/posix";
import * as windows from "jsr:@std/path/windows";

Converting from a file url to a directory can be done simply by the `fromFileUrl` method from the appropriate implementation.

const p1 = posix.fromFileUrl("file:///home/foo");
const p2 = windows.fromFileUrl("file:///home/foo");
console.log(`Path 1: ${p1} Path 2: ${p2}`);

We can also choose to not specify the platform and automatically use whatever Deno is running on

const p3 = path.fromFileUrl("file:///home/foo");
console.log(`Path on current OS: ${p3}`);

We can get the last part of a file path using the basename method

const p = path.basename("./deno/is/awesome/mod.ts");
console.log(p); // mod.ts

We can get the directory of a file path using the dirname method

const base = path.dirname("./deno/is/awesome/mod.ts");
console.log(base); // ./deno/is/awesome

We can get the extension of a file path using the extname method

const ext = path.extname("./deno/is/awesome/mod.ts");
console.log(ext); // .ts

We can format a path using a FormatInputPathObject

const formatPath = path.format({
  root: "/",
  dir: "/home/user/dir",
  ext: ".html",
  name: "index",
});
console.log(formatPath); // "/home/user/dir/index.html"

When we want to make our code cross-platform, we can use the join method. This joins any number of string by the OS-specific file separator. On Mac OS this would be foo/bar. On windows, this would be foo\bar.

const joinPath = path.join("foo", "bar");
console.log(joinPath);

We can get the current working directory using the built-in cwd method

const current = Deno.cwd();
console.log(current);

Run this example locally using the Deno CLI:

deno run --allow-read https://docs.deno.com/examples/path-operations.ts

Path operations

Additional resources