sequelize instanceMethods - node.js

Question

I'm trying to configurate my database ,i want the data returned to user doesn't include some sensetive data, so i'm adding an instanceMethods named toPublicJSON that using a function named pick from underscoreJS , but when i use this function (toPublicJSON) I encounter an error : that toPublicJSON is not a function
this my database configuration:
var bcrypt = require("bcrypt");
var _ = require("underscore");
module.exports = function(sequelize, DataType) {
return sequelize.define('users', {
email: {
type: DataType.STRING,
allowNull: false,
unique: true,
validate: {
isEmail: true
}
},
salt: {
type: DataType.STRING
},
hassedPassword: {
type: DataType.STRING
},
password: {
type: DataType.VIRTUAL,
allowNull: false,
validate: {
len: [7, 100]
},
set: function(value) {
var salt = bcrypt.genSaltSync(10);
var hashed_password = bcrypt.hashSync(value, salt);
this.setDataValue('password', value);
this.setDataValue("salt", salt);
this.setDataValue("hassedPassword", hashed_password);
}
}
}, {
hooks: {
beforeValidate: function(user, option) {
if (typeof user.email == 'string')
user.email = user.email.toLowerCase();
}
},
instanceMethods:{
toPublicJSON: function() {
var json = this.toJSON();
return _.pick(json, 'id', 'email', 'createdAt', 'updatedAt');
}
}
});
}
my code :
app.post('/users',function(req,res){
var body=_.pick(req.body,"email","password");
db.users.create(body).then(function(user){
return res.send(user.toPublicJSON());
},function(e){
return res.status(400).json(e);
})
});
and this is the error :

Answer 1

Assuming you are using the latest version of Sequelize they changed slightly how to define instance and class methods. You need to assign functions to the prototype of the result of sequelize.define('users');. You will need to save the results of sequelize.define to a variable, similar to below...
const User = sequelize.define('users', {});
User.prototype.toPublicJSON = function() {
// Your code here
};
return User;
If you're on version 3 let me know.
Good luck :)
EDIT: Further reading material http://docs.sequelizejs.com/manual/tutorial/models-definition.html#expansion-of-models
EDIT 2: You may want to look into scopes. They are essentially pre-baked filters you can apply to your data when querying for them. http://docs.sequelizejs.com/manual/tutorial/scopes.html
If you did that then you could say
sequelize.define('users', {
// Attributes...
}, {
scopes: {
public: {
attributes: ['id', 'email', 'createdAt', 'updatedAt']
}
}
});
db.users.scope('public').findOne({...});