array-find-predecessor


Find a predecessor value of the array that should be chosen when a given index is deleted

``javascript
import arrayFindPredecessor from 'array-find-predecessor';

const array = ['foo', 'bar', 'baz'];

arrayFindPredecessor(array, 1); //=> 'foo'
arrayFindPredecessor(array, 2); //=> 'bar'

arrayFindPredecessor(array, 0); //=> 'bar'
`

Installation

$3

`
npm install array-find-predecessor
`

$3

`
bower install array-find-predecessor
`

API

$3

array: Array (non-empty array)
index: Number (index of the array assumed to be deleted)
Return: Number or null

Essentially, it returns an array value one index before the given index.

`
value: A B C
deleted: ^
substitute: ^
`

`javascript
arrayFindPredecessor(['A', 'B', 'C'], 1); //=> 'A'
`

If index is 0, it returns the successor value because the first element has no predecessor elements.

`
value: A B C
deleted: ^
substitute: ^
`

`javascript
arrayFindPredecessor(['A', 'B', 'C'], 0); //=> 'B'
`

If the array includes only a single value, it returns null because no value exists except for the deleted value.

`
value: A
deleted: ^
substitute: (none)
`

`javascript
arrayFindPredecessor(['A'], 0); //=> null
``

License

Copyright (c) 2016 Shinnosuke Watanabe

Licensed under the MIT License.