escalade

> A tiny (183B to 210B) and fast utility to ascend parent directories

With escalade, you can scale parent directories until you've found what you're looking for.
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:
> Please note that `escalade` only deals with direct ancestry – it will not dive into parents' sibling directories.

# </blockquote>

Notice: As of v3.1.0, `escalade` now includes Deno support! Please see Deno Usage below.

# Install

$ npm install --save escalade

# Modes

There are two "versions" of `escalade` available:

### "async"

> Node.js: >= 8.x
> Size (gzip): 210 bytes
> Availability: CommonJS, ES Module

This is the primary/default mode. It makes use of `async`/`await` and `util.promisify`.

### "sync"

> Node.js: >= 6.x
> Size (gzip): 183 bytes
> Availability: CommonJS, ES Module

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

//~> 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.
If your `callback` was never satisfied, then `escalade` will resolve/return with nothing (undefined).

> Important:
> The `sync` and `async` versions share the same API.
> 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.
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.
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 is identical and that there are still two modes from which to choose:

// 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 - A tiny (247B) utility to remove items recursively
- totalist - A tiny (195B to 224B) utility to recursively list all (total) files in a directory
- mk-dirs - A tiny (420B) utility to make a directory and its parents, recursively

# License

MIT © Luke Edwards