couchdb generic update handler.js

function (doc,req) {
    if(!req.id)
        return [null,{ message : "Support only PUT with id" }];

    if(!doc)
        doc = { "_id":req.id };
    
    var data = JSON.parse(req.body);
    delete data._id;
    delete data.id;

    function MergeObject(origin,obj) {
        var arr = Object.keys(obj);
        arr.forEach(function(key) {
            if(obj[key] instanceof Object && !Array.isArray(obj[key]))
            {
                if(!origin[key])
                    origin[key] = {};

                obj[key]    = MergeObject(origin[key],obj[key]);
                if(Object.keys(obj[key]).length < 1)
                    delete obj[key];
            }
            else if(obj[key] === null)
            {
                if(origin[key])
                    delete origin[key];
                else delete obj[key];
            }
            else if(origin[key] === obj[key])
                delete obj[key];
            else origin[key] = obj[key];
        });

        return obj;
    }

    data    = MergeObject(doc,data);
    return [doc,JSON.stringify(data)];
}