mongoose save vs insert vs create

The .save() is an instance method of the model, while the .create() is called directly from the Model as a method call, being static in nature, and takes the object as a first parameter.

var mongoose = require('mongoose');

var notificationSchema = mongoose.Schema({
    "datetime" : {
        type: Date,
        default: Date.now
    },
    "ownerId":{
        type:String
    },
    "customerId" : {
        type:String
    },
    "title" : {
        type:String
    },
    "message" : {
        type:String
    }
});

var Notification = mongoose.model('Notification', notificationsSchema);


function saveNotification1(data) {
    var notification = new Notification(data);
    notification.save(function (err) {
        if (err) return handleError(err);
        // saved!
    })
}

function saveNotification2(data) {
    Notification.create(data, function (err, small) {
    if (err) return handleError(err);
    // saved!
    })
}

Export whatever functions you would want outside.

More at the Mongoose Docs, or consider reading the reference of the Model prototype in Mongoose.