# escalade [](https://github.com/lukeed/escalade/actions) [](https://licenses.dev/npm/escalade) [](https://codecov.io/gh/lukeed/escalade)
> A tiny (183B to 210B) and [fast](#benchmarks) utility to ascend parent directories
With [escalade](https://en.wikipedia.org/wiki/Escalade), you can scale parent directories until you've found what you're looking for.<br>Given an input file or directory, `escalade` will continue executing your callback function until either:
1) the callback returns a truthy value
2) `escalade` has reached the system root directory (eg, `/`)
> **Important:**<br>Please note that `escalade` only deals with direct ancestry – it will not dive into parents' sibling directories.
---
**Notice:** As of v3.1.0, `escalade` now includes [Deno support](http://deno.land/x/escalade)! Please see [Deno Usage](#deno) below.
---
## Install
```
$ npm install --save escalade
```
## Modes
There are two "versions" of `escalade` available:
#### "async"
> **Node.js:** >= 8.x<br>
> **Size (gzip):** 210 bytes<br>
> **Availability:** [CommonJS](https://unpkg.com/escalade/dist/index.js), [ES Module](https://unpkg.com/escalade/dist/index.mjs)
This is the primary/default mode. It makes use of `async`/`await` and [`util.promisify`](https://nodejs.org/api/util.html#util_util_promisify_original).
#### "sync"
> **Node.js:** >= 6.x<br>
> **Size (gzip):** 183 bytes<br>
> **Availability:** [CommonJS](https://unpkg.com/escalade/sync/index.js), [ES Module](https://unpkg.com/escalade/sync/index.mjs)
This is the opt-in mode, ideal for scenarios where `async` usage cannot be supported.
## Usage
***Example Structure***
```
/Users/lukeed
└── oss
├── license
└── escalade
├── package.json
└── test
└── fixtures
├── index.js
└── foobar
└── demo.js
```
***Example Usage***
```js
//~> demo.js
import { join } from 'path';
import escalade from 'escalade';
const input = join(__dirname, 'demo.js');
// or: const input = __dirname;
const pkg = await escalade(input, (dir, names) => {
console.log('~> dir:', dir);
console.log('~> names:', names);
console.log('---');
if (names.includes('package.json')) {
// will be resolved into absolute
return 'package.json';
}
});
//~> dir: /Users/lukeed/oss/escalade/test/fixtures/foobar
//~> names: ['demo.js']
//---
//~> dir: /Users/lukeed/oss/escalade/test/fixtures
//~> names: ['index.js', 'foobar']
//---
//~> dir: /Users/lukeed/oss/escalade/test
//~> names: ['fixtures']
//---
//~> dir: /Users/lukeed/oss/escalade
//~> names: ['package.json', 'test']
//---
console.log(pkg);
//=> /Users/lukeed/oss/escalade/package.json
// Now search for "missing123.txt"
// (Assume it doesn't exist anywhere!)
const missing = await escalade(input, (dir, names) => {
console.log('~> dir:', dir);
return names.includes('missing123.txt') && 'missing123.txt';
});
//~> dir: /Users/lukeed/oss/escalade/test/fixtures/foobar
//~> dir: /Users/lukeed/oss/escalade/test/fixtures
//~> dir: /Users/lukeed/oss/escalade/test
//~> dir: /Users/lukeed/oss/escalade
//~> dir: /Users/lukeed/oss
//~> dir: /Users/lukeed
//~> dir: /Users
//~> dir: /
console.log(missing);
//=> undefined
```
> **Note:** To run the above example with "sync" mode, import from `escalade/sync` and remove the `await` keyword.
## API
### escalade(input, callback)
Returns: `string|void` or `Promise<string|void>`
When your `callback` locates a file, `escalade` will resolve/return with an absolute path.<br>
If your `callback` was never satisfied, then `escalade` will resolve/return with nothing (undefined).
> **Important:**<br>The `sync` and `async` versions share the same API.<br>The **only** difference is that `sync` is not Promise-based.
#### input
Type: `string`
The path from which to start ascending.
This may be a file or a directory path.<br>However, when `input` is a file, `escalade` will begin with its parent directory.
> **Important:** Unless given an absolute path, `input` will be resolved from `process.cwd()` location.
#### callback
Type: `Function`
The callback to execute for each ancestry level. It always is given two arguments:
1) `dir` - an absolute path of the current parent directory
2) `names` - a list (`string[]`) of contents _relative to_ the `dir` parent
> **Note:** The `names` list can contain names of files _and_ directories.
When your callback returns a _falsey_ value, then `escalade` will continue with `dir`'s parent directory, re-invoking your callback with new argument values.
When your callback returns a string, then `escalade` stops iteration immediately.<br>
If the string is an absolute path, then it's left as is. Otherwise, the string is resolved into an absolute path _from_ the `dir` that housed the satisfying condition.
> **Important:** Your `callback` can be a `Promise/AsyncFunction` when using the "async" version of `escalade`.
## Benchmarks
> Running on Node.js v10.13.0
```
# Load Time
find-up 3.891ms
escalade 0.485ms
escalade/sync 0.309ms
# Levels: 6 (target = "foo.txt"):
find-up x 24,856 ops/sec ±6.46% (55 runs sampled)
escalade x 73,084 ops/sec ±4.23% (73 runs sampled)
find-up.sync x 3,663 ops/sec ±1.12% (83 runs sampled)
escalade/sync x 9,360 ops/sec ±0.62% (88 runs sampled)
# Levels: 12 (target = "package.json"):
find-up x 29,300 ops/sec ±10.68% (70 runs sampled)
escalade x 73,685 ops/sec ± 5.66% (66 runs sampled)
find-up.sync x 1,707 ops/sec ± 0.58% (91 runs sampled)
escalade/sync x 4,667 ops/sec ± 0.68% (94 runs sampled)
# Levels: 18 (target = "missing123.txt"):
find-up x 21,818 ops/sec ±17.37% (14 runs sampled)
escalade x 67,101 ops/sec ±21.60% (20 runs sampled)
find-up.sync x 1,037 ops/sec ± 2.86% (88 runs sampled)
escalade/sync x 1,248 ops/sec ± 0.50% (93 runs sampled)
```
## Deno
As of v3.1.0, `escalade` is available on the Deno registry.
Please note that the [API](#api) is identical and that there are still [two modes](#modes) from which to choose:
```ts
// Choose "async" mode
import escalade from 'https://deno.land/escalade/async.ts';
// Choose "sync" mode
import escalade from 'https://deno.land/escalade/sync.ts';
```
> **Important:** The `allow-read` permission is required!
## Related
- [premove](https://github.com/lukeed/premove) - A tiny (247B) utility to remove items recursively
- [totalist](https://github.com/lukeed/totalist) - A tiny (195B to 224B) utility to recursively list all (total) files in a directory
- [mk-dirs](https://github.com/lukeed/mk-dirs) - A tiny (420B) utility to make a directory and its parents, recursively
## License
MIT © [Luke Edwards](https://lukeed.com)
