I'm trying to make a function that merges arrays. The reason is, I have a function that supposed to get the settings of an entity, and merge them with the global defaults.

//So for example, let's say globalOptions is something like this
var globalOptions={opt1:'foo',opt2:'something'};
//and this is entityOptions
var entityOptions={opt1:'foofoo',opt2:null};

The only difference is it has objects in objects and objects in objects in objects, so what I made was a function that loops through all objects, thinking I would later, easily be able to loop through it all. Please ignore the array thing. That is defected, but unneeded.

function loopObj(obj, call, where, objcall, array) {
    if ($.isArray(obj) || $.isPlainObject(obj)) {
        for (i in obj) {
            if ($.isArray(obj)) {
                if (array) {
                    loopObj(obj[i], call, where[where.length] = i, true);
                    if (objcall) {
                        call(obj[i],where,true);
                        }
                    }
                    else {
                    loopObj(obj[i], call, where+'['+i+']', false);
                    if (objcall) {
                        call(obj[i],where,true);
                        }
                    }
                }
            else {
                if (array) {
                    loopObj(obj[i], call, where[where.length] = parseInt(i), true);
                    if (objcall) {
                        call(obj[i],where,true);
                        }
                    }
                    else {
                    loopObj(obj[i], call, where+'[\''+i+'\']', false);
                    if (objcall) {
                        call(obj[i],where,true);
                        }
                    }
                }
            }
        }
        else {
            return call(obj,where);
            }
    } 

Then I made this program to convert it:

function mergeObj(a,b) {
    temp.retd = new Object();
    loopObj(a,function (c,d) {
        if (c) {
            eval(d.replace('%par%','temp.retd'))=c;
            }
        else {
            eval(d.replace('%par%','temp.retd'))=eval(d.replace('%par%','b'));
            }
        },'%par%', true);
    return temp.retd();
    }

I get the error:

Uncaught ReferenceError: Invalid left-hand side in assignment
(anonymous function)base.js:51
loopObjbase.js:40
loopObjbase.js:31
mergeObjbase.js:46
(anonymous function)base.js:72

I know what it means, the eval returns an anonomys variable (copy of the variable), so I can't set it, only get it.