Meteor package that compares two objects with the same _id in a before and after state and returns a corresponding mongo update query.
Sometimes it's practical to get an object from the database, modify the object and put it back directly in the database. However minimongo doesn't allow to do that since collections on the client could be filtered through publications, hence minimongo update operation only allow fields modifications, not objects replacement.
This package solves this problem by building the appropriate update query to go from oldObject to newObject.
meteor add vjau:jsdiff2mongo
The package exports a single function jsDiff2mongo(oldObject, newObject)
Let say you have an object from minimongo
var oldObj = Coll.findOne({});
console.log(oldObj);
// {_id:"xyz123", a:1}Now you do some modifications
var newObj = _.clone(oldObj);
newObj.b = 2;And call the comparison function
var diff = jsDiff2Mongo(oldObj, newObj);
console.log(diff);
//[{_id:"xyz123"},{"$set":{b:2}}]You get an array which you can apply to minimongo with
Mongo.Collection.prototype.update.apply(diff);0r you can use the helper package vjau:mongo-extend which does all that for you
Methods are ignored (not serializable by Mongo)
Arrays with variations are replaced in place instead of complicated addtoset queries