Error callback for collection operations

[anisart]

I set unique field check for collection

Genres._ensureIndex({title: 1}, {unique: true});

and if I add document with same title to list I have an error in console

insert failed: MongoError: insertDocument :: caused by :: 11000 E11000 duplicate key error index: meteor.genres.$title_1  dup key: { : "New title" }

I want show alert message with error like a

webix.message("Document with same title is exist!");

but I don't know where paste this code.

Need add error callback to save section of meteor-data.js