第六章 生命周期函数 Hook

有的时候，我们希望在存储之前干点什么，比如把用户的密码进行 Hash 一下。这个时候就需要用到生命周期函数了。

生命周期函数有哪些？有哪些种类？

支持的生命周期函数如下

(1)
  beforeBulkCreate(instances, options)
  beforeBulkDestroy(options)
  beforeBulkUpdate(options)
(2)
  beforeValidate(instance, options)
(-)
  validate
(3)
  afterValidate(instance, options)
  - or -
  validationFailed(instance, options, error)
(4)
  beforeCreate(instance, options)
  beforeDestroy(instance, options)
  beforeUpdate(instance, options)
  beforeSave(instance, options)
  beforeUpsert(values, options)
(-)
  create
  destroy
  update
(5)
  afterCreate(instance, options)
  afterDestroy(instance, options)
  afterUpdate(instance, options)
  afterSave(instance, options)
  afterUpsert(created, options)
(6)
  afterBulkCreate(instances, options)
  afterBulkDestroy(options)
  afterBulkUpdate(options)

这些周期函数分为全局的与模型级别的。

全局级别

const sequelize = new Sequelize(..., {
    define: {
        hooks: {
            beforeCreate: () => {
                // Do stuff
            }
        }
    }
});

模型级别

const Project = sequelize.define('project', {}, {
    hooks: {
        beforeCreate: () => {
            // Do other stuff
        }
    }
});

定义生命周期的三种方式

1.options

const Project = sequelize.define('project', {}, {
    hooks: {
        beforeCreate: () => {
            // Do other stuff
        }
    }
});

const sequelize = new Sequelize(..., {
    define: {
        hooks: {
            beforeCreate: () => {
                // Do stuff
            }
        }
    }
});

2.调用对应的方法

sequelize.afterValidate('xxx', () => {....})
User.afterValidate('myHookAfter', (user, options) => {
  user.username = 'Toni';
});

3.调用 addHook

sequelize.addHook('xxx', () => {....})
User.addHook('afterValidate', 'notifyUsers', () => {....})

命名生命周期函数

取一个叫 notifyUsers 的名字

User.afterValidate('myHookAfter', (user, options) => {
  user.username = 'Toni';
});

User.addHook('afterValidate', 'notifyUsers', () => {....})

移除生命周期函数

只有被命名了的生命周期函数才可移除

Book.removeHook('afterValidate', 'notifyUsers');