How to split an array into 2, left and right

Question

I have an array of menu links ['A','B','C','D','X','Y','Z'] and I want to split them into an array with this result {'left':['A','B','C','D'], 'right': ['X', 'Y','Z']}. I want them split in half. The number of items in the list can variable. What is the easiest way to do this?

Answer 1

You can use Array.prototype.slice to extract subarrays from an array:

var arr = ['A','B','C','D','X','Y','Z'],
    mid = Math.ceil(arr.length/2),
    obj = {
        left: arr.slice(0, mid),
        right: arr.slice(mid)
    };

If you don't mind altering the original array, you can also use Array.prototype.splice:

var arr = ['A','B','C','D','X','Y','Z'],
    obj = {
        left: arr.splice(0, Math.ceil(arr.length/2)),
        right: arr
    };

Answer 2

Split array into two parts with slice function.

var numbers= [1,2,3,4,5,6,7,8,9,10],
    leftEnd= Math.ceil(numbers.length/2),
    result= {
        left: numbers.slice(0,leftEnd),
        right: numbers.slice(leftEnd)
    };