javaScript function that merges two JSON objects with the second object taking precedence in the event of a collision.

mergeDeep.js

function mergeDeep (o1, o2) {
    var tempNewObj = o1;

    //if o1 is an object - {}
    if (o1.length === undefined && typeof o1 !== "number") {
        $.each(o2, function(key, value) {
            if (o1[key] === undefined) {
                tempNewObj[key] = value;
            } else {
                tempNewObj[key] = mergeDeep(o1[key], o2[key]);
            }
        });
    }

    //else if o1 is an array - []
    else if (o1.length > 0 && typeof o1 !== "string") {
        $.each(o2, function(index) {
            if (JSON.stringify(o1).indexOf(JSON.stringify(o2[index])) === -1) {
                tempNewObj.push(o2[index]);
            }
        });
    }

    //handling other types like string or number
    else {
        //taking value from the second object o2
        //could be modified to keep o1 value with tempNewObj = o1;
        tempNewObj = o2;
    }
    return tempNewObj;
};

what about boolean ?

o1.length === undefined && typeof o1 !== "number" is true for boolean variables

Works like a charm! Thanks!
Also I edited it to only use vanilla JavaScript (FINALLY FIGURED OUT HOW TO USE CODE BLOCK FORMATTING PROPERLY):

function mergeDeep (o1, o2) {
    var tempNewObj = o1;

    //if o1 is an object - {}
    if (o1.length === undefined && typeof o1 !== "number") {
        for(key in o2) {
            value=o2[key]
            if (o1[key] === undefined) {
                tempNewObj[key] = value;
            } else {
                tempNewObj[key] = mergeDeep(o1[key], o2[key]);
            }
        }
    }

    //else if o1 is an array - []    I THINK I BROKE IT ._.
    else if (o1.length > 0 && typeof o1 !== "string") {
        for(index in o2) {
            if (JSON.stringify(o1).indexOf(JSON.stringify(o2[index])) === -1) {
                tempNewObj.push(o2[index]);
            }
        }
    }

    //handling other types like string or number
    else {
        //taking value from the second object o2
        //could be modified to keep o1 value with tempNewObj = o1;
        tempNewObj = o2;
    }
    return tempNewObj;
}