# Resolve Parent Path
[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url]
> Resolve a path by walking parent directories.
## Installation
```bash
npm install @stdlib/fs-resolve-parent-path
```
## Usage
```javascript
var resolveParentPath = require( '@stdlib/fs-resolve-parent-path' );
```
#### resolveParentPath( path\[, options], clbk )
Asynchronously resolves a path by walking parent directories.
```javascript
resolveParentPath( 'package.json', onPath );
function onPath( error, path ) {
if ( error ) {
throw error;
}
console.log( path );
// => '...'
}
```
The function accepts the following `options`:
- **dir**: base directory from which to begin walking. May be either an absolute path or a path relative to the current working directory.
By default, the function begins walking from the current working directory. To specify an alternative directory, set the `dir` option.
```javascript
var opts = {
'dir': __dirname
};
resolveParentPath( 'package.json', opts, onPath );
function onPath( error, path ) {
if ( error ) {
throw error;
}
console.log( path );
// => '...'
}
```
#### resolveParentPath.sync( path\[, options] )
Synchronously resolves a path by walking parent directories.
```javascript
var path = resolveParentPath.sync( 'package.json' );
// returns '...'
```
The function accepts the same `options` as [`resolveParentPath()`](#resolve-parent-path).
## Notes
- If unable to resolve a path, both functions return `null`.
- This implementation is **not** similar in functionality to core [`path.resolve`][node-core-path-resolve]. The latter performs string manipulation to generate a full path. This implementation walks parent directories to perform a **search**, thereby touching the file system. Accordingly, this implementation resolves a _real_ absolute file path and is intended for use when a target's location in a parent directory is unknown relative to a child directory; e.g., when wanting to find a package root from deep within a package directory.
## Examples
```javascript
var resolveParentPath = require( '@stdlib/fs-resolve-parent-path' );
var opts = {
'dir': __dirname
};
/* Sync */
var out = resolveParentPath.sync( 'package.json', opts );
// returns '...'
out = resolveParentPath.sync( 'non_existent_basename' );
// returns null
/* Async */
resolveParentPath( 'package.json', opts, onPath );
resolveParentPath( './../non_existent_path', onPath );
function onPath( error, path ) {
if ( error ) {
throw error;
}
console.log( path );
}
```
* * *
## CLI
## Installation
To use the module as a general utility, install the module globally
```bash
npm install -g @stdlib/fs-resolve-parent-path
```
### Usage
```text
Usage: resolve-parent-path [options]
Options:
-h, --help Print this message.
-V, --version Print the package version.
--dir dir Base search directory.
```
### Examples
```bash
$ resolve-parent-path package.json
```
* * *
## Notice
This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.
For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].
#### Community
[![Chat][chat-image]][chat-url]
---
## License
See [LICENSE][stdlib-license].
## Copyright
Copyright © 2016-2022. The Stdlib [Authors][stdlib-authors].
[npm-image]: http://img.shields.io/npm/v/@stdlib/fs-resolve-parent-path.svg
[npm-url]: https://npmjs.org/package/@stdlib/fs-resolve-parent-path
[test-image]: https://github.com/stdlib-js/fs-resolve-parent-path/actions/workflows/test.yml/badge.svg
[test-url]: https://github.com/stdlib-js/fs-resolve-parent-path/actions/workflows/test.yml
[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/fs-resolve-parent-path/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/fs-resolve-parent-path?branch=main
[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules
[deno-url]: https://github.com/stdlib-js/fs-resolve-parent-path/tree/deno
[umd-url]: https://github.com/stdlib-js/fs-resolve-parent-path/tree/umd
[esm-url]: https://github.com/stdlib-js/fs-resolve-parent-path/tree/esm
[chat-image]: https://img.shields.io/gitter/room/stdlib-js/stdlib.svg
[chat-url]: https://gitter.im/stdlib-js/stdlib/
[stdlib]: https://github.com/stdlib-js/stdlib
[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors
[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/fs-resolve-parent-path/main/LICENSE
[node-core-path-resolve]: https://nodejs.org/api/path.html#path_path_resolve_paths
[@stdlib/fs/resolve-parent-path-by]: https://www.npmjs.com/package/@stdlib/fs-resolve-parent-path-by