Sequelize typescript NO association methods

Question

I don't think my problem is the most difficult, but I haven't really been able to make any progress with it for some time.

What is my problem ?

I use sequelize with typescript in my backend, and I want to create associations between tables / models (many-to-many / m:n). After creating these associations, it seems that I cannot access the "magic methods" (i.e. the methods generated by sequelize to make the association easier to use).

// association between tasks and employees was defined

const task = await DB.Tasks.findByPk(1) 
// task.addEmployee() or such methods doesnt exist! 

Using sequelize v6.37.2

What have I tried ?

Before we get to my code, I would like to give you a little important information first.

console.log(mymodel.associations) // works, no error  

will return my definied asscoation. I have also searched on github for a repository that might use a similar structure to my models (official sequelize docs template) but to no avail. I tried to stick to the official sequelize docs:

https://sequelize.org/docs/v6/other-topics/typescript/

My code

Here is one of my models (the other one has the same structure):

// Task is a simple interface containing all attributes
export type TaskCreationAttributes = Optional<Task, "id">

export class TaskModel extends Model<Task, TaskCreationAttributes> {
    declare id: number
    declare name: string
    declare description: string
}

export default function (sequelize: Sequelize): typeof TaskModel {
    TaskModel.init(
        {
            id: {
                autoIncrement: true,
                primaryKey: true,
                type: DataTypes.INTEGER,
            },
            name: {
                allowNull: false,
                type: DataTypes.STRING(255),
            },
            description: {
                allowNull: true,
                type: DataTypes.TEXT,
            } 
        },
        {
            tableName: "tasks",
            sequelize,
        },
    )

    

    TaskModel.belongsToMany(EmployeeModel, { through: "task_positions"})
    EmployeeModel.belongsToMany(TaskModel, { through: "task_positions"})

    return TaskModel
}

Answer 1

You need to declare such "magic" methods explicitly using provided mixin interfaces from Sequelize (see the link you mentioned):

declare getEmployees: BelongsToManyGetAssociationsMixin<Emplyee>;