Declaring Hooks

Arguments to hooks are passed by reference. This means, that you can change the values, and this will be reflected in the insert / update statement. A hook may contain async actions - in this case the hook function should return a promise.

There are currently three ways to programmatically add hooks:

  1. // Method 1 via the .init() method
  2. class User extends Model {}
  3. User.init({
  4.   username: DataTypes.STRING,
  5.   mood: {
  6.     type: DataTypes.ENUM,
  7.     values: ['happy', 'sad', 'neutral']
  8.   }
  9. }, {
  10.   hooks: {
  11.     beforeValidate: (user, options) => {
  12.       user.mood = 'happy';
  13.     },
  14.     afterValidate: (user, options) => {
  15.       user.username = 'Toni';
  16.     }
  17.   },
  18.   sequelize
  19. });
  21. // Method 2 via the .addHook() method
  22. User.addHook('beforeValidate', (user, options) => {
  23.   user.mood = 'happy';
  24. });
  26. User.addHook('afterValidate', 'someCustomName', (user, options) => {
  27.   return Promise.reject(new Error("I'm afraid I can't let you do that!"));
  28. });
  30. // Method 3 via the direct method
  31. User.beforeCreate((user, options) => {
  32.   return hashPassword(user.password).then(hashedPw => {
  33.     user.password = hashedPw;
  34.   });
  35. });
  37. User.afterValidate('myHookAfter', (user, options) => {
  38.   user.username = 'Toni';
  39. });