在模型验证中获取this.id返回未定义

Question

I'm getting this as undefined on field's validate, but the same occurs even if I set in third argument of Sequelize.define to use other fields as documentation describes.

module.exports = function (sequelize, DataTypes) {

const User = sequelize.define(
    'User', 
    {...}, //all fields here
    {
        freezeTableName: true,
        paranoid: true,
        validate: {
            isPasswordRepeated: () => {
                console.log(this.id, this.password);
            }
        }
    }
);

}

In this code, console.log outputs undefined undefined . If I use on password's validate, still gets undefined for this.id , but receives password through argument. I've looked for solutions, but it seems a rare problem and only found this abandoned issue on GitHub. Is there another way to get this.id ?

Sequelize version 4.42.0

Answer 1

You're not understanding the context of 'this'.

Inside a function, the value of this depends on how the function is called.

...

Since the following code is not in strict mode, and because the value of this is not set by the call, this will default to the global object, which is window in a browser.

...

In strict mode, however, if the value of this is not set when entering an execution context, it remains as undefined.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/this#Function_context