array.partial

array.partial

Like array.some but with exclusivity

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 component.

Why

array.some returns true when at least one element matches. 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, callback)

API

partial(array, callback)

array

Type: Array - Input array

callback

Type: Function - Function is a predicate, to test each element of the array. This is called with same arguments as array.filter

Examples

const partial = require('array.partial')

const myArr = [{id: 'a1', checked: true}, {id: 'a2', checked: false}]
partial(myArr, x => x.checked)  // -> true

// ...

const myArr = [{id: 'a1', checked: true}, {id: 'a2', checked: true}]
partial(myArr, x => x.checked)  // -> false

// ...

const myArr = [{id: 'a1', checked: false}, {id: 'a2', checked: false}]
partial(myArr, x => x.checked)  // -> false

License

MIT © Hrusikesh Panda