forked from M3-Academy/challenge-algorithms-v2.0
212 lines
6.7 KiB
Markdown
212 lines
6.7 KiB
Markdown
# escalade [](https://github.com/lukeed/escalade/actions) [](https://codecov.io/gh/lukeed/escalade)
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> A tiny (183B to 210B) and [fast](#benchmarks) utility to ascend parent directories
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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:
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1) the callback returns a truthy value
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2) `escalade` has reached the system root directory (eg, `/`)
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> **Important:**<br>Please note that `escalade` only deals with direct ancestry – it will not dive into parents' sibling directories.
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---
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**Notice:** As of v3.1.0, `escalade` now includes [Deno support](http://deno.land/x/escalade)! Please see [Deno Usage](#deno) below.
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---
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## Install
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```
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$ npm install --save escalade
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```
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## Modes
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There are two "versions" of `escalade` available:
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#### "async"
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> **Node.js:** >= 8.x<br>
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> **Size (gzip):** 210 bytes<br>
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> **Availability:** [CommonJS](https://unpkg.com/escalade/dist/index.js), [ES Module](https://unpkg.com/escalade/dist/index.mjs)
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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).
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#### "sync"
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> **Node.js:** >= 6.x<br>
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> **Size (gzip):** 183 bytes<br>
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> **Availability:** [CommonJS](https://unpkg.com/escalade/sync/index.js), [ES Module](https://unpkg.com/escalade/sync/index.mjs)
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This is the opt-in mode, ideal for scenarios where `async` usage cannot be supported.
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## Usage
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***Example Structure***
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```
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/Users/lukeed
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└── oss
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├── license
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└── escalade
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├── package.json
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└── test
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└── fixtures
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├── index.js
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└── foobar
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└── demo.js
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```
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***Example Usage***
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```js
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//~> demo.js
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import { join } from 'path';
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import escalade from 'escalade';
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const input = join(__dirname, 'demo.js');
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// or: const input = __dirname;
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const pkg = await escalade(input, (dir, names) => {
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console.log('~> dir:', dir);
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console.log('~> names:', names);
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console.log('---');
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if (names.includes('package.json')) {
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// will be resolved into absolute
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return 'package.json';
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}
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});
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//~> dir: /Users/lukeed/oss/escalade/test/fixtures/foobar
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//~> names: ['demo.js']
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//---
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//~> dir: /Users/lukeed/oss/escalade/test/fixtures
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//~> names: ['index.js', 'foobar']
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//---
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//~> dir: /Users/lukeed/oss/escalade/test
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//~> names: ['fixtures']
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//---
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//~> dir: /Users/lukeed/oss/escalade
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//~> names: ['package.json', 'test']
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//---
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console.log(pkg);
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//=> /Users/lukeed/oss/escalade/package.json
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// Now search for "missing123.txt"
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// (Assume it doesn't exist anywhere!)
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const missing = await escalade(input, (dir, names) => {
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console.log('~> dir:', dir);
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return names.includes('missing123.txt') && 'missing123.txt';
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});
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//~> dir: /Users/lukeed/oss/escalade/test/fixtures/foobar
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//~> dir: /Users/lukeed/oss/escalade/test/fixtures
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//~> dir: /Users/lukeed/oss/escalade/test
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//~> dir: /Users/lukeed/oss/escalade
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//~> dir: /Users/lukeed/oss
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//~> dir: /Users/lukeed
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//~> dir: /Users
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//~> dir: /
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console.log(missing);
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//=> undefined
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```
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> **Note:** To run the above example with "sync" mode, import from `escalade/sync` and remove the `await` keyword.
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## API
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### escalade(input, callback)
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Returns: `string|void` or `Promise<string|void>`
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When your `callback` locates a file, `escalade` will resolve/return with an absolute path.<br>
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If your `callback` was never satisfied, then `escalade` will resolve/return with nothing (undefined).
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> **Important:**<br>The `sync` and `async` versions share the same API.<br>The **only** difference is that `sync` is not Promise-based.
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#### input
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Type: `string`
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The path from which to start ascending.
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This may be a file or a directory path.<br>However, when `input` is a file, `escalade` will begin with its parent directory.
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> **Important:** Unless given an absolute path, `input` will be resolved from `process.cwd()` location.
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#### callback
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Type: `Function`
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The callback to execute for each ancestry level. It always is given two arguments:
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1) `dir` - an absolute path of the current parent directory
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2) `names` - a list (`string[]`) of contents _relative to_ the `dir` parent
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> **Note:** The `names` list can contain names of files _and_ directories.
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When your callback returns a _falsey_ value, then `escalade` will continue with `dir`'s parent directory, re-invoking your callback with new argument values.
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When your callback returns a string, then `escalade` stops iteration immediately.<br>
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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.
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> **Important:** Your `callback` can be a `Promise/AsyncFunction` when using the "async" version of `escalade`.
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## Benchmarks
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> Running on Node.js v10.13.0
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```
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# Load Time
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find-up 3.891ms
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escalade 0.485ms
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escalade/sync 0.309ms
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# Levels: 6 (target = "foo.txt"):
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find-up x 24,856 ops/sec ±6.46% (55 runs sampled)
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escalade x 73,084 ops/sec ±4.23% (73 runs sampled)
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find-up.sync x 3,663 ops/sec ±1.12% (83 runs sampled)
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escalade/sync x 9,360 ops/sec ±0.62% (88 runs sampled)
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# Levels: 12 (target = "package.json"):
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find-up x 29,300 ops/sec ±10.68% (70 runs sampled)
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escalade x 73,685 ops/sec ± 5.66% (66 runs sampled)
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find-up.sync x 1,707 ops/sec ± 0.58% (91 runs sampled)
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escalade/sync x 4,667 ops/sec ± 0.68% (94 runs sampled)
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# Levels: 18 (target = "missing123.txt"):
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find-up x 21,818 ops/sec ±17.37% (14 runs sampled)
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escalade x 67,101 ops/sec ±21.60% (20 runs sampled)
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find-up.sync x 1,037 ops/sec ± 2.86% (88 runs sampled)
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escalade/sync x 1,248 ops/sec ± 0.50% (93 runs sampled)
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```
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## Deno
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As of v3.1.0, `escalade` is available on the Deno registry.
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Please note that the [API](#api) is identical and that there are still [two modes](#modes) from which to choose:
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```ts
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// Choose "async" mode
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import escalade from 'https://deno.land/escalade/async.ts';
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// Choose "sync" mode
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import escalade from 'https://deno.land/escalade/sync.ts';
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```
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> **Important:** The `allow-read` permission is required!
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## Related
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- [premove](https://github.com/lukeed/premove) - A tiny (247B) utility to remove items recursively
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- [totalist](https://github.com/lukeed/totalist) - A tiny (195B to 224B) utility to recursively list all (total) files in a directory
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- [mk-dirs](https://github.com/lukeed/mk-dirs) - A tiny (420B) utility to make a directory and its parents, recursively
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## License
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MIT © [Luke Edwards](https://lukeed.com)
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