A safer way to mix JSON objects to be used as config or POST data.

property-mixer.js

function mixin() {
    return JSON.parse('{'
        + [].reduce.call(arguments, function (prev, cur) {
            var str = JSON.stringify(cur);
            if (!str || str.slice(0, 1) !== '{' || str.slice(-1) !== '}') {
                throw new Error('Invalid object: ' + str);
            }
            return (prev ? prev + ',' : '')
            + str.slice(1, -1);
        }, null)
        + '}'
    );
}

obj1 = {a:1, b:2};
obj2 = {b:3, c: 4, d: [1,2,3]}

console.log(mixin(obj1, obj2));
//console.log(mixin(obj1, obj2, [1,2,3]));
//console.log(mixin(obj1, obj2, function(){}));