https://github.com/mrchief/array.partial

When you want array.some but not array.every
https://github.com/mrchief/array.partial

array every filter partial some

Last synced: 10 days ago
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When you want array.some but not array.every

• Host: GitHub
• URL: https://github.com/mrchief/array.partial
• Owner: mrchief
• License: mit
• Created: 2018-03-25T02:50:07.000Z (almost 7 years ago)
• Default Branch: master
• Last Pushed: 2019-06-27T02:57:33.000Z (over 5 years ago)
• Last Synced: 2024-11-29T03:44:49.386Z (29 days ago)
• Topics: array, every, filter, partial, some
• Language: JavaScript
• Homepage:
• Size: 43 KB
• Stars: 1
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# array.partial [![Build Status](https://travis-ci.org/mrchief/array.partial.svg?branch=master)](https://travis-ci.org/mrchief/array.partial)

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---

> When you want array.some but not array.every

Useful when you need to determine "partially" selected states - like partially selecting tree nodes when some but not all child nodes are checked.

In fact, the idea originated while building a feature for my own [react-dropdown-tree-select](https://github.com/dowjones/react-dropdown-tree-select) component.

## Why

[array.some](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/some) returns true when _at least one_ element matches. [array.every](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/every) returns true when _all_ elements match. `array.some` will also return true when `array.every` returns true.

`array.partial` is something in between. It returns `true` **only, and only when** _some_ (but not all) elements match. If all elements match, then it'll return `false`.

This can also be achieved with `array.some && !array.every` if you don't mind iterating over the array twice. This module does it with one iteration over the array.

## Install

```

npm install array.partial

```

## Usage

```

const partial = require('array.partial')

partial(array, predicate)

```

## API

### partial(array, predicate)

Return true if and only if some elements pass the check, otherwise false.

#### array

Type: `Array` - Input array

#### predicate

Type: `Function` - A predicate, to test each element of the array. This is called with the following arguments:

`element` - The current element being processed in the array

`index` (Optional) - The index of the current element being processed in the array.

`array` (Optional) - The array filter was called upon.

## Examples

```

const partial = require('array.partial')

const myArr = [{id: 'a1', checked: true}, {id: 'a2', checked: false}]

partial(myArr, x => x.checked)  // -> returns true

// ...

const myArr = [{id: 'a1', checked: true}, {id: 'a2', checked: true}]

partial(myArr, x => x.checked)  // -> returns false

// ...

const myArr = [{id: 'a1', checked: false}, {id: 'a2', checked: false}]

partial(myArr, x => x.checked)  // -> returns false

```

## License

MIT © [Hrusikesh Panda](https://about.me/hkpanda)