denodb: Uncaught ReferenceError: Cannot access 'Model' before initialization

Hello, I encountered this error when trying to achieve one-to-many relationship error: Uncaught ReferenceError: Cannot access 'UserModel' before initialization userId: Relationships.belongsTo(UserModel),

I have 2 models Article

import {
  DataTypes,
  Model,
  Relationships,
} from "https://deno.land/x/denodb/mod.ts";
import { UserModel } from "./user.ts";
export class ArticleModel extends Model {
  static table = "articles";
  static timestamps = true;

  static fields = {
    id: { primaryKey: true, autoIncrement: true },
    content: DataTypes.TEXT,
    title: DataTypes.STRING,
    tags: DataTypes.ENUM,
    likeCount: DataTypes.INTEGER,
    userId: Relationships.belongsTo(UserModel),
  };

  static user() {
    return this.hasOne(UserModel);
  }
}

User

import { ArticleModel } from "./article.ts";

export class UserModel extends Model {
  static table = "users";
  static timestamps = true;

  static fields = {
    id: { primaryKey: true, autoIncrement: true },
    username: DataTypes.STRING,
    password: DataTypes.STRING,
  };

  static articles() {
    return this.hasMany(ArticleModel);
  }
}

Seems like a cyclic dependency problem here because User class references Article class and vice versa. Please help

About this issue

Original URL
State: closed
Created 4 years ago
Comments: 16 (5 by maintainers)

Most upvoted comments

Hey guys,

I think the way this could be done without cyclic dependencies is by taking the relationships outside of the model definition.

At the moment, if you make a one-to-one relationship (or many-to-many, etc.), it has to be done this way:

import { Relationships } from 'https://deno.land/x/denodb/mod.ts';

// After both models declarations

Relationships.oneToOne(Business, Owner);

// Before database linking

I could change the belongsTo API so you could have:

// models/article
export class Article extends Model {
  static table = "articles";
  static timestamps = true;

  static fields = {
    id: { primaryKey: true, autoIncrement: true },
    // ...
  };

  static user() {
    return this.hasOne(User);
  }
}

// app
// Create userId in Article
Relationships.belongsTo(Article, User);

Also, thank you so much for your patience. I only got back to help recently, didn’t have the time before.

Anyways, let me know what you think or feel free to suggest another syntax 😃

eveningkid on Apr 17, 2021

Hey guys,

I think the way this could be done without cyclic dependencies is by taking the relationships outside of the model definition.

At the moment, if you make a one-to-one relationship (or many-to-many, etc.), it has to be done this way:
import { Relationships } from 'https://deno.land/x/denodb/mod.ts';

// After both models declarations

Relationships.oneToOne(Business, Owner);

// Before database linking
I could change the belongsTo API so you could have:
// models/article
export class Article extends Model {
  static table = "articles";
  static timestamps = true;

  static fields = {
    id: { primaryKey: true, autoIncrement: true },
    // ...
  };

  static user() {
    return this.hasOne(User);
  }
}

// app
// Create userId in Article
Relationships.belongsTo(Article, User);
Also, thank you so much for your patience. I only got back to help recently, didn’t have the time before.

Anyways, let me know what you think or feel free to suggest another syntax 😃

This is what I’m looking for !

siegen1192 on Apr 18, 2021

@eveningkid, I was checking this issue (I’m in this situation right now)… How about let pass the table name directly to the belongsTo parameter. Something like:

export class ArticleModel extends Model {
  static table = "articles";
  static timestamps = true;

  static fields = {
    id: { primaryKey: true, autoIncrement: true },
    content: DataTypes.TEXT,
    title: DataTypes.STRING,
    tags: DataTypes.ENUM,
    likeCount: DataTypes.INTEGER,
    userId: Relationships.belongsTo("users"), // Here
  };

  static user() {
    return this.hasOne(UserModel);
  }
}

So we avoid falling in the typescript error @hoangph271 said. Solutions for desperate moments

stillalivx on Apr 17, 2021

I think this is more of a coding problem than a denodb problem…!
You can avoid cyclic dependency by just declaring all models in a single file…?

hoangph271 on Sep 2, 2020