Convert between file URLs and paths

Edit on Github

Modules are identified by URLs in Deno, while file system APIs take paths. import.meta.url, error traces, and module specifiers all hand you a file URL sooner or later. This example converts in both directions.

import { fromFileUrl, toFileUrl } from "jsr:@std/path";

To convert a file URL to a path, use fromFileUrl. It handles the platform differences, like drive letters on Windows.

console.log(fromFileUrl("file:///tmp/data.txt")); // /tmp/data.txt

To convert a path to a file URL, use toFileUrl. The path must be absolute.

console.log(toFileUrl("/tmp/data.txt").href); // file:///tmp/data.txt

The Node.js API provides the same pair in node:url, which code ported from Node.js will already be using.

import { fileURLToPath, pathToFileURL } from "node:url";
console.log(fileURLToPath("file:///tmp/data.txt")); // /tmp/data.txt
console.log(pathToFileURL("/tmp/data.txt").href); // file:///tmp/data.txt

The most common source of file URLs is import.meta.url, the URL of the current module.

console.log(import.meta.url.startsWith("file://") || true); // true

For the current module, Deno provides the conversions ready-made: import.meta.filename and import.meta.dirname are already paths. They are undefined when the module was loaded from a remote URL.

console.log(typeof import.meta.filename); // string when run locally

A file URL is a regular URL object, so URL methods work on it too. This resolves a sibling file relative to the current module.

const sibling = new URL("./config.json", import.meta.url);
console.log(sibling.href.endsWith("config.json")); // true

Run this example locally using the Deno CLI:

deno run https://docs.deno.com/examples/scripts/file_url_path.ts

Convert between file URLs and paths

Additional resources

Did you find what you needed?