callback - Sequelize - 在最后一次回调执行完成后从第二级链返回对象

Question

在 addBussiness 方法中，我创建了一个业务对象，然后使用结果在数据库中使用 sequelize 创建一个 UserBusiness 对象。

我想返回在 UserBusiness 对象创建完成后创建的 Business 对象。

就目前而言，我认为由于 Javascript 的异步性质，在 UserBusiness 对象创建完成之前返回业务对象。

有没有办法从第二个回调中的第一个回调返回对象？

addBusiness(_,args) {
      // this is needed to put it correctly in the geometry point format that the database expects
      var point = { type: 'Point', coordinates: [args.input.location.longitude,args.input.location.latitude] }; 
      args.input.location = point;

      return Business.create(args.input, {
        include: [{
          association: Hours,
          as: 'hours'
        }]
      }).then(business => {
        UserBusiness.create({userId: args.input.userId, businessId: business.businessId})
        return business; // this might get returned before UserBusiness.create is done executing
      })
    },

这是我在 Sequelize 中定义的映射:

UserAccountModel.belongsToMany(BusinessModel, { through: UserBusinessModel, foreignKey: 'user_id'});
BusinessModel.belongsToMany(UserAccountModel, { through: UserBusinessModel , foreignKey: 'business_id'});

Answer 1

您可以在创建后返回 UserBusiness 对象，然后返回 UserBusiness.bussiness 或将业务对象保存在一个变量中，并在 UserBusiness 对象创建后返回该变量。

addBusiness(_,args) {
      var point = { type: 'Point', coordinates: [args.input.location.longitude,args.input.location.latitude] }; 
      args.input.location = point;

      return Business.create(args.input, {
        include: [{
          association: Hours,
          as: 'hours'
        }]
      }).then(business => {
        return UserBusiness.create({userId: args.input.userId, businessId: business.businessId})
      }).then(UserBusiness => {
        return UserBusiness.business;
      })
    }

或

addBusiness(_,args) {
  var _business;
  var point = { type: 'Point', coordinates: [args.input.location.longitude,args.input.location.latitude] }; 
  args.input.location = point;

  return Business.create(args.input, {
    include: [{
      association: Hours,
      as: 'hours'
    }]
  }).then(business => {
    _business = business;
    return UserBusiness.create({userId: args.input.userId, businessId: business.businessId})
  })
   .then(() => {
     return _business;
  })
}