Ecosyste.ms: Awesome
An open API service indexing awesome lists of open source software.
https://github.com/shannonmoeller/list-promise
Maximally-concurrent Promise-based array iteration.
https://github.com/shannonmoeller/list-promise
Last synced: 18 days ago
JSON representation
Maximally-concurrent Promise-based array iteration.
- Host: GitHub
- URL: https://github.com/shannonmoeller/list-promise
- Owner: shannonmoeller
- License: mit
- Created: 2016-03-31T12:42:29.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2018-01-20T22:38:43.000Z (almost 7 years ago)
- Last Synced: 2024-04-26T12:20:40.628Z (7 months ago)
- Language: JavaScript
- Homepage: http://npm.im/list-promise
- Size: 36.1 KB
- Stars: 4
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: readme.md
- License: license
Awesome Lists containing this project
README
# `list-promise`
[![NPM version][npm-img]][npm-url] [![Downloads][downloads-img]][npm-url] [![Build Status][travis-img]][travis-url] [![Coverage Status][coveralls-img]][coveralls-url] [![Tip][amazon-img]][amazon-url]
Maximally-concurrent Promise-aware array manipulation via `ListPromise`. They're like the plural form of a Promise or a finite Observable.
## Install
$ npm install --save list-promise
## Usage
```js
import list from 'list-promise';
import { readFile, writeFile } from 'fs-promise';
// Promisify an array.
list(['src/foo.txt', 'src/bar.txt'])
// Read each file (callback returns a Promise).
.map((path) => readFile(path, 'utf8'))
// Chunk the characters of each file.
.map((file) => file.split(''))
// Merge the chunks into a single array.
.concat()
// Remove empty chunks.
.filter((file) => file.length > 0)
// Sort the characters.
.sortBy((x) => x)
// Reverse the characters.
.reverse()
// Join chunks into a string.
.reduce((bundle, file) => bundle + file, '')
// Write result to a new file.
.then((bundle) => writeFile('dist/bundle.txt', bundle));
```
## API
### listPromise(list) : ListPromise
- `list` `Array|Promise` A list of items which may or may not be Promises.
Creates a promise with `map`, `filter`, and `reduce` methods that can be used to iterate over list items as they are resolved.
### ListPromise
#### .map(fn): ListPromise
- `fn` `Function(item, i) : item` Map callback.
Creates a new `ListPromise` for the results of mapping a list with a given map function.
```js
list(['a', 'b'])
.map((x) => x.toUpperCase());
.then(console.log);
// -> ['A', 'B']
```
#### .mapProp(key, fn): ListPromise
- `key` `String|Number` Key of property to modify.
- `fn` `Function(property, i, item) : item` Map callback.
Creates a new `ListPromise` for the results of mapping a list of items' properties with a given map function.
```js
list([{ foo: 'a' }, { foo: 'b' }])
.mapProp('foo', (x) => x.toUpperCase());
.then(console.log);
// -> [{ foo: 'A' }, { foo: 'B' }]
```
#### .concat(): ListPromise
Flattens a list of lists into a single list.
```js
list([['a'], ['b'], ['b', 'c']])
.concat();
.then(console.log);
// -> ['a', 'b', 'b', 'c']
```
#### .concatMap(fn): ListPromise
- `fn` `Function(item, i) : item` Map callback.
Convenience shorthand for `.map(fn).concat()`.
```js
list([{ foo: 'ab' }, { foo: 'bc' }])
.concatMap((x) => x.foo.split(''));
.then(console.log);
// -> ['a', 'b', 'b', 'c']
```
#### .filter(fn): ListPromise
- `fn` `Function(item, i) : context` Filter callback.
Creates a new `ListPromise` for the results of filtering a list with a given filter function.
```js
list([0, 10, 1, 9, 2, 8])
.filter((x) => x > 5);
.then(console.log);
// -> [10, 9, 8]
```
#### .reduce(fn, [initialValue]): ListPromise
- `fn` `Function(context, item, i) : context` Reduce callback.
- `initialValue` `*` (default: `undefined`) Initial value to pass to the reducer.
Creates a new `ListPromise` for the result of reducing a list with a given reducer function. If the reduction results in an array, that array may then be iterated.
```js
list([0, 10, 1, 9, 2, 8])
.reduce((x, y) => x + y, 1);
.then(console.log);
// -> 31
```
#### .reverse(): ListPromise
Creates a new `ListPromise` for the result of reversing the list.
```js
list(['a', 'b', 'c', 1, 2, 3])
.reverse()
.then(console.log);
// -> [3, 2, 1, 'c', 'b', 'a']
```
#### .sortBy(fn): ListPromise
- `fn` `Function(item, i) : any` Sort value getter.
Creates a new `ListPromise` for the result of sorting a list with a property getter function.
```js
list([{ foo: '3' }, { foo: '1' }, { foo: '2' }])
.sortBy((x) => x.foo);
.then(console.log);
// -> [{ foo: '1' }, { foo: '2' }, { foo: '3' }]
```
## Contribute
Standards for this project, including tests, code coverage, and semantics are enforced with a build tool. Pull requests must include passing tests with 100% code coverage and no linting errors.
### Test
$ npm test
----
MIT © [Shannon Moeller](http://shannonmoeller.com)
[amazon-img]: https://img.shields.io/badge/amazon-tip_jar-yellow.svg?style=flat-square
[amazon-url]: https://www.amazon.com/gp/registry/wishlist/1VQM9ID04YPC5?sort=universal-price
[coveralls-img]: http://img.shields.io/coveralls/shannonmoeller/list-promise/master.svg?style=flat-square
[coveralls-url]: https://coveralls.io/r/shannonmoeller/list-promise
[downloads-img]: http://img.shields.io/npm/dm/list-promise.svg?style=flat-square
[npm-img]: http://img.shields.io/npm/v/list-promise.svg?style=flat-square
[npm-url]: https://npmjs.org/package/list-promise
[travis-img]: http://img.shields.io/travis/shannonmoeller/list-promise/master.svg?style=flat-square
[travis-url]: https://travis-ci.org/shannonmoeller/list-promise