runtime:path

Modern, platform-aware path utilities. Pure computation — no I/O. The host platform and working directory come from runtime:process, so separators and resolve() follow the real OS.

Capability: Env

Exposed as an ES module under the runtime: scheme. Status: Available.

One platform-correct surface — no posix/win32 dual namespaces and no overloaded signatures — plus first-class file: URL interop: dirname(fromFileURL(import.meta.url)) is the modern __dirname.

Import

JavaScript

import { join, resolve, dirname, fromFileURL } from "runtime:path";

// The modern __dirname: the directory of the current module.
const here = dirname(fromFileURL(import.meta.url));
const cfg = resolve(here, "config", "app.json");

Exports

Export	Type	Description	Example
`sep`	`string`	Path segment separator for the host OS (`"/"` or `"\"`).	`sep; // "/" on POSIX`
`delimiter`	`string`	Path list delimiter for the host OS (`":"` or `";"`).	`env.PATH.split(delimiter)`
`isAbsolute(p)`	`(string) => boolean`	Whether `p` is an absolute path.	`isAbsolute("/etc/hosts") // true`
`normalize(p)`	`(string) => string`	Collapses `.` / `..` and redundant separators.	`normalize("/a/./b/../c") // "/a/c"`
`join(...segments)`	`(...string) => string`	Joins segments with the separator, then normalizes.	`join("src", "lib", "x.js") // "src/lib/x.js"`
`resolve(...segments)`	`(...string) => string`	Resolves to an absolute path, anchoring at `cwd()` if no segment is absolute.	`resolve("data", "out.json")`
`dirname(p)`	`(string) => string`	The directory portion of `p`.	`dirname("/var/log/app.log") // "/var/log"`
`basename(p)`	`(string) => string`	The final segment of `p` (no suffix-stripping overload).	`basename("/var/log/app.log") // "app.log"`
`extname(p)`	`(string) => string`	The extension of the final segment, including the dot (or empty).	`extname("archive.tar.gz") // ".gz"`
`parse(p)`	`(string) => object`	`{ root, dir, base, name, ext }`.	`parse("/a/b.txt")`
`relative(from, to)`	`(string, string) => string`	Relative path from `from` to `to` (both resolved first).	`relative("/a/b", "/a/c/d") // "../c/d"`
`fromFileURL(url)`	`(string \| URL) => string`	Converts a `file:` URL to a path.	`fromFileURL(import.meta.url)`
`toFileURL(p)`	`(string) => URL`	Converts a path (resolved to absolute) to a `file:` URL.	`toFileURL("/a/b.txt").href // "file:///a/b.txt"`

Errors

Error	When
`TypeError`	A path segment isn't a string, or `fileURLToPath()` gets a non-`file:` URL. (Pure string functions — no capability, no I/O.)