value-at

This is a simple JavaScript getter/setter function for retrieving or changing a value in an array.

Installation

npm install value-at --save

Usage

Quick guide to the syntax:

valueAt(array, index[, replacementValue][, isCloned])

Using as a get function

Positive

var valueAt = require('value-at');
 
var array = [1, 2, 3, 4, 5];
 
var value = valueAt(array, 1);
 
// value = 2

That isn't all that special since you can do the same thing with native JavaScript by just using array[1].

The advantage this has is that it also works for negative index values.

Negative

var valueAt = require('value-at');
 
var array = [1, 2, 3, 4, 5];
 
var value = valueAt(array, -2);
 
// value = 4

Using as a set function

Positive

var valueAt = require('value-at');
 
var array = [1, 2, 3, 4, 5];
 
var newArray = valueAt(array, 1, "a");
 
// array = [1, 2, 3, 4, 5];
// newArray = [1, "a", 3, 4, 5];

Note that valueAt doesn't change the original array by default. It returns with an altered shallow clone of the original array.

Negative

var valueAt = require('value-at');
 
var array = [1, 2, 3, 4, 5];
 
var newArray = valueAt(array, -2, "b");
 
// array = [1, 2, 3, 4, 5];
// newArray = [1, 2, 3, "b", 5];

Altering the original array

If you do want to alter the original array, set the 4th parameter to false.

var valueAt = require('value-at');
 
var array = [1, 2, 3, 4, 5];
 
valueAt(array, -2, "b", false);
 
// array = [1, 2, 3, "b", 5];