Merge Object & Array: Javascript, JQuery

Illustrative example:

d1 = {
  "ean_code": ["OA13233394CN08", "8903327046534", "8903327014779"],
  "balance_qty": [5, 10, 15]
}

And

d2 = {
  "ean_code": ["OA13233394CN11", "OA13233394CN08", "8903327014779", "OA13233394CN09"],
  "scanned_qty": [30, 5, 20, 10, - 1],
}

Output:

d3 = {
  "ean_code": ["OA13233394CN08", "8903327046534", "8903327014779", "OA13233394CN11", "OA13233394CN09"],
  "scanned_qty": [5, 0, 20, 30, 10],
  "balance_qty": [5, 10, 15, 0, 0]
}

Explaination. d3['scanned_qty'][1] default value is 0, because value of d3['ean_code'][1] is belongs to d1['ean_code'] array and d1 object doesn't have scanned_qty key.

Best possible way to do this operation?

Solution

You just need a custom solution for your specific case.

Merge 2 objects with no sub-objects (no recursion required)
Final object's array fields must be the same length
Final object's array fields must preserve index coherency
Final object's array fields must use '0' as a default value

http://jsfiddle.net/8X5yB/4/

function customMerge(a, b, uniqueKey) {
    var result = {};
    var temp = {};
    var fields = {};
    // object 1
    for(var x=0; x<a[uniqueKey].length; x++) {
        id = a[uniqueKey][x];
        if(temp[id] == null) temp[id] = {};
        for(k in a) {
            if(k != uniqueKey) {
                fields[k] = '';
                temp[id][k] = (a[k].length > x ? a[k][x] : 0);
            }
        }
    }
    // object 2
    for(var x=0; x<b[uniqueKey].length; x++) {
        id = b[uniqueKey][x];
        if(temp[id] == null) temp[id] = {};
        for(k in b) {
            if(k != uniqueKey) {
                fields[k] = '';
                temp[id][k] = (b[k].length > x ? b[k][x] : 0);
            }
        }
    }
    // create result
    result[uniqueKey] = [];
    for(f in fields) result[f] = [];
    for(k in temp) {
        result[uniqueKey].push(k);
        for(f in fields) {
            result[f].push(temp[k][f] != null ? temp[k][f] : 0);
        }
    }
    return result;
}
...
var obj = customMerge(d1, d2, "ean_code");