runkit-example.js

require('mysql2')
const { format } = require('sql-formatter')
const { ORM, Model, PrimaryKeyType, StringType, StringNotNullType, DateType, NumberNotNullType } = require('taichi-orm')

/*
 * Runkit doesn't support Class Properties
 * So we assign properties in constructor
 */
class ShopModel extends Model{
  constructor(...args){
    super(...args)
    this.id = this.field(PrimaryKeyType)
    this.name = this.field(new StringType({length: 100}))
    this.products = ShopModel.hasMany(ProductModel, 'shopId')
  }
}

class ColorModel extends Model{
  constructor(...args){
    super(...args)
    this.id = this.field(PrimaryKeyType)
    this.code = this.field(new StringNotNullType({length: 50}))
  }
}

class ProductColorModel extends Model{
  constructor(...args){
    super(...args)
    this.id = this.field(PrimaryKeyType)
    this.productId = this.field(NumberNotNullType)
    this.colorId = this.field(NumberNotNullType)
    this.type = this.field(new StringNotNullType({length: 50}))
  }
}

class ProductModel extends Model{
  constructor(...args){
    super(...args)
    this.id = this.field(PrimaryKeyType)
    this.name = this.field(new StringType({length: 100}))
    this.createdAt = this.field(DateType)
    this.shopId = this.field(NumberNotNullType)
    this.shop = ProductModel.belongsTo(ShopModel, 'shopId')
    this.colors = ProductModel.hasManyThrough(ProductColorModel, ColorModel, 'id', 'colorId', 'productId')
    //computed property created based on colors
    this.colorsWithType = ProductModel.compute( (parent, type = 'main') => {
      return parent.$.colors({
        where: ({through}) => through.type.equals(type)
      })
    })
  }
}

(async() =>{
    // configure database
    const orm = new ORM({
        models: {
          Shop: ShopModel, 
          Product: ProductModel, 
          Color: ColorModel, 
          ProductColor: ProductColorModel
        },
        knexConfig: {
            client: 'mysql2'
        }
    })
   
    const { Shop, Product, Color, ProductColor } = orm.getContext().repos

    // computed fields are the relations
    // you can do complicated query in one go
    // Graph-like selecting Models "Shop > Product > Color"
    let records = await Shop.find({
      select: {
        products: {
          select: {
            colors: {
              limit: 2
            },
            colorsWithType: 'main'
          }
        }
      }
    }).getBuilder().toSqlString()

  console.log('print the sql', format(records))


})()