A special feature to find next\prev item in array only when item has value. Will be skipped all unnecessary items by their id's.

nextPrevItem.js

// Go to the next item.
function nextIndex(index, arr){
    var item = null;
    var minI = 0;
    var i = index;
    while (i < arr.length) {
        i++;
        if (i == arr.length) { i = minI; }
        if (arr[i].id && arr[i].val) { item = arr[i]; break;}
    }
    return item;
}

// Go to the previous item.
function prevIndex(index, arr){
    var item = null;
    var maxI = arr.length;
    var i = index;
    while (i > 0) {
        i--;
        if (arr[i].id && arr[i].val) { item = arr[i]; break;}
        if (i == 0) { i = maxI; }
    }
    return item;
}

// Tests.
const arr = [{id:0, val: null}, {id:1, val: null}, {id:2, val: 32}, {id:3, val: null}, {id:4, val: 53}];

nextIndex(2, arr); // {id:4, val: 53}
nextIndex(4, arr); // {id:2, val: 32}
prevIndex(4, arr); // {id:2, val: 32}

// http://plnkr.co/edit/fYpXo1mFRWPxrLlgr123?p=preview