a little exercise showing how to use mongoose middleware

mongoose middleware showcase

var mongoose = require('mongoose');
var Schema = mongoose.Schema;

var blogSchema = new Schema({
    title:  String,
    author: String,
    body:   String,
    date: { type: Date, default: Date.now }
});

var blogModel = mongoose.model('Blog', blogSchema);

mongoose.connect("mongodb://localhost/mwtest", function (err) {
    // if we failed to connect, abort
    if (err) {
        throw err;
    } else {
        console.log("DB connected succesfully");
    }

    blogSchema.pre('save', function preSave(next) {
        this._wasNew = this.isNew;
        console.log("pre save of doc: " + this._id);
        next();
    });

    blogSchema.post('save', function (doc) {
        if (doc._wasNew) {
            console.log("created new doc: " + doc._id);

        } else {
            console.log("updated doc: " + doc._id);
        }
        return true;
    });

    blogSchema.post('remove', function (doc) {
       console.log("post remove of doc: " + doc._id);
    });

    blogSchema.pre('remove', function (next) {
       console.log("pre remove of doc: " + this._id);
        next();
    });

    blogModel.create({title: 'Philip is good', author: 'George'}).then(function (doc) {
        console.log("create callback doc: " + JSON.stringify(doc));
        blogModel.findById(doc._id, function (err, doc) {
            doc.remove();
            console.log("after removal of doc: " + doc._id);

        });
    });

});

And the output is:
DB connected succesfully
pre save of doc: 527a14f93cf78b8e04000001
created new doc: 527a14f93cf78b8e04000001
create callback doc: {"__v":0,"title":"Philip is good","author":"George","_id":"527a14f93cf78b8e04000001","date":"2013-11-06T10:07:53.327Z"}
pre remove of doc: 527a14f93cf78b8e04000001
after removal of doc: 527a14f93cf78b8e04000001
post remove of doc: 527a14f93cf78b8e04000001