Mastering Mongoose: Middleware, Validation & Virtuals

Why Mongoose?

Mongoose provides a straight-forward, schema-based solution to model your application data. It includes built-in type casting, validation, query building, business logic hooks and more.

Middleware (Hooks)

Middleware are functions which are passed control during execution of asynchronous functions.

userSchema.pre('save', async function(next) {
  if (!this.isModified('password')) return next();
  this.password = await bcrypt.hash(this.password, 12);
  next();
});

Virtuals

Virtuals are document properties that you can get and set but that do not get persisted to MongoDB.

userSchema.virtual('fullName').get(function() {
  return this.name.first + ' ' + this.name.last;
});

Populate

Mongoose's populate() method lets you reference documents in other collections. It's powerful but use it wisely to avoid N+1 query problems.