Standard library / path · on the one-page reference

path

Stable — pure string manipulation, no filesystem calls of its own. Newly added to Lumen, but resting on one of the oldest, least-churned corners of the runtime.

No filesystem access, just string logic. A practical subset of Node's path API — POSIX only (no path.win32), and path.sep/path.delimiter are called as path.sep()/path.delimiter() rather than read as properties, since Lumen has no static-namespace constant mechanism yet.

basename dirname extname isAbsolute normalize join resolve parse format sep delimiter
path.basename(path, suffix?)

(string, string?) → string — the last path segment, with suffix stripped if present.

console.log(path.basename("/foo/bar/baz.html"));        // baz.html
console.log(path.basename("/foo/bar/baz.html", ".html")); // baz
path.dirname(path)

string → string — returns "." for a path with no directory segment.

console.log(path.dirname("/foo/bar/baz.html")); // /foo/bar
path.extname(path)

string → string — "" for dotfiles like .gitignore.

console.log(path.extname("index.html")); // .html
path.isAbsolute(path)

string → bool

console.log(path.isAbsolute("/foo/bar")); // true
path.normalize(path)

string → string — collapses ./.. segments; does not require the path to exist.

console.log(path.normalize("/foo/bar//baz/asdf/quux/..")); // /foo/bar/baz/asdf
path.join(...paths)

(string, string, ...) → string — 2 to 6 arguments; joins then normalizes, matching Node's join definition.

console.log(path.join("/foo", "bar", "baz/asdf", "quux", "..")); // /foo/bar/baz/asdf
path.resolve(...paths)

(string, string, ...) → string — 1 to 6 arguments; "cd"-chains left to right, an absolute segment resets the result. If no argument is absolute, anchors to the real working directory to guarantee an absolute result, matching Node. The only path.* function that reads the real cwd — every other one stays pure string manipulation.

console.log(path.resolve("/foo/bar", "./baz")); // /foo/bar/baz
console.log(path.resolve("foo", "bar"));        // /foo/bar
path.parse(path)

string → { root, dir, base, name, ext } — the second record-returning builtin after fs.statSync.

const p = path.parse("/home/user/dir/file.txt");
console.log(p.dir);   // /home/user/dir
console.log(p.name);  // file
path.format(parts)

{ root, dir, base, name, ext } → string — the inverse of parse. Deviation from Node: all five fields are required (Node allows omitting any of them); round-tripping path.format(path.parse(p)) works perfectly, building a literal by hand needs every field filled in.

console.log(path.format(path.parse("/home/user/dir/file.txt")));
// /home/user/dir/file.txt
path.sep()

→ string — always "/" (Lumen is POSIX-only). Called as a function, not read as a property (see above).

console.log(path.sep()); // /
path.delimiter()

→ string — always ":".

console.log(path.delimiter()); // :