javascript - 在观察者中发布附加游标

Question

我有一个如下所示的文档。

{
  _id: ObjectId,
  orders: [ObjectId, ObjectId]
}

对这些订单的查找将产生类似这样的结果

{
  _id: ObjectId,
  products: [ObjectId, ObjectId, ObjectId]
}

现在我的出版物将找到并观察父 Meteor.users。

Meteor.publish(function () {
  let handle = Meteor.users.find(this.userId).observe({
    added: doc => {
      // publish all orders
      // publish all products within that order
    },
    changed: doc => { /** same as above */ }
  });
  this.ready();
  this.onStop(() => handle.stop());
});

当其中任何一个发生变化时，我想修改顶级文档并发布它。也就是说:

this.changed('user', doc._id, publishRelations(doc));

对于 meteor 来说这可能吗？

Answer 1

您应该能够使用peerlibrary:reactive-publish 来做到这一点。您只需将要发布的光标包装在出版物中的自动运行中即可。只要 react 性依赖项之一(在本例中为三个游标)发生变化，就应该重新运行它:

Meteor.publish("userOrders", function() {
   var self = this;
   self.autorun(function() {
      var productIds = [];

      // get logged in user
      var userCursor = Meteor.users.find(self.userId);

      //  get orders belonging to logged in user
      var ordersCursor = Orders.find({userId: self.userId});


      // create array of product Ids from user's orders  
      // You could probably make this better by omitting duplicates  
      ordersCursor.forEach(function(doc, index) {
        _.each(doc.products, function(productId) {
           productIds.push(productId);
         });
      });

      // get products in array
      var productsCursor = Products.find({ _id: { $in : productIds } });

      // return array of cursors
      return [
         userCursor,
         ordersCursor,
         productsCursor
      ];

   });

});