How to add custom function to sequelize.js in Node.JS?

Question

For example I have a Client model. I want to add new function "sendEmail"

The function needs to work send email to one client, or to send email to many clients at once?

Where to define those functions?

Answer 1

Version 4 of sequelize has changed this and the other solutions with instanceMethods and classMethods do not work anymore. See Upgrade to V4 / Breaking changes

The new way of doing it is as follows:

const Model = sequelize.define('Model', {
    ...
});

// Class Method
Model.myCustomQuery = function (param, param2) {  };

// Instance Method
Model.prototype.myCustomSetter = function (param, param2) {  }

Answer 2

Use instanceMethods as Jan Meier pointed out.

In your client sample:

// models/Client.js
'use strict';

module.exports = function(sequelize, DataTypes) {
  return sequelize.define('Client', {
    first_name: DataTypes.STRING,
    last_name: DataTypes.STRING,
  }, {
    instanceMethods: {
      getFullName: function() {
        return this.first_name + ' ' + this.last_name;
      }
    }
  });
};

Answer 3

https://sequelize.org/v4/manual/tutorial/upgrade-to-v4.html#config-options

Removed classMethods and instanceMethods options from sequelize.define. Sequelize models are now ES6 classes. You can set class / instance level methods like this

Old

const Model = sequelize.define('Model', {
    ...
}, {
    classMethods: {
        associate: function (model) {...}
    },
    instanceMethods: {
        someMethod: function () { ...}
    }
});

New

const Model = sequelize.define('Model', {
    ...
});

// Class Method
Model.associate = function (models) {
    ...associate the models
};

// Instance Method
Model.prototype.someMethod = function () {..}