类方法和实例方法有什么区别[sequelize]

Question

Sequelize allows you to add custom methods to a model , and there are two ways to do so:

• classMethods: {}
• instanceMethods: {}

In Sequelize I can't find an explanation about the differences of this two objects. Could anyone explain the difference with an example when to use one or the other?

Answer 1

Class is the object you get when you call sequelize.define . It stands for the whole table.

var User = sequelize.define('user', {...});

Instance is like one unit of that class, ie a row in the collection's table:

User.create({}).then(function(user) {
  // `user` is an instance.
});

Class methods are functions that don't expect an instance. You can call those like this:

User.myMethod();

Instance methods are ones that operate on a single instance. You can call them like this:

user.myMethod();

this in class methods is a class. this in instance methods is an instance (obviously).