boo.js

const { DataTypes } = require('sequelize');
const ApplicationRecord = require('./application-record');

const Foo = require('./foo');

const Boo = ApplicationRecord.define('Boo', {
  fooId: DataTypes.INTEGER,
  booName: DataTypes.STRING
}, {});


// Boo.belongsTo(Foo); <= 這樣會噴掉, 因為跟 Foo 有循環引用, boo 就變成 defefined
Boo.belongsTo(ApplicationRecord.define('foo'), { as: 'foo' });

module.exports = Boo;

foo.js

const { DataTypes } = require('sequelize');
const ApplicationRecord = require('./application-record');

const Boo = require('./boo');

const Definetion = ApplicationRecord.define('Foo', {
  firstName: DataTypes.STRING,
  lastName: DataTypes.STRING,
  email: DataTypes.STRING
}, {});

class Foo extends Definetion {
  toJSON() {
    const data = this.get();

    return {
      ...data,
      email: undefined
    };
  }

  getBooName() {
    console.log('======');
  }
}

Foo.hasMany(Boo); // <= include 的時候會變成 Boos
// Foo.hasMany(Boo, { as: 'boos' }) <= include 的時候會變成 boos

module.exports = Foo;

test-koa.js

const Koa = require('koa');
const Router = require('koa-router');

const Foo = require('./models/foo');
const Boo = require('./models/boo');

const app = new Koa();

const router = new Router();

router.get('/foo', async (ctx) => {
  const foo = await Foo.create({ firstName: 'Calvin', lastName: 'Huang' });
  ctx.body = foo;
});

router.get('/boo', async (ctx) => {
  const boo = await Boo.create({ fooId: 1, booName: 'Kevin' });
  ctx.body = boo;
});

router.get('/', async (ctx) => {
  const foo = await Foo.find({ where: 1, include: [Boo] });

  foo.getBooName();

  ctx.body = foo;
});

app.use(router.routes());

app.listen('3003', () => {
  console.log('> Listen on port 3003');
});