Mapping two array with native functions into objects, each object differs by parent array.

two_array_iteration.js

var a = [1,2,3,4,5];
var b = [11,12,13,14];
var length = a.length;
var c = a.concat(b).map(function(value, index) {
    return {
        value: value,
        isA: index >= length
    }
});