meteor :Deps.autorun 内的 collection.find().fetch() 失败

Question

我想在 meteor 服务器上创建一个响应式(Reactive)集合查询，并在有变化时处理结果。

这是我的代码:

if (Meteor.isServer) {
  Meteor.startup(function(){
    Deps.autorun(function(){
      var items=new Meteor.Collection('name').find().fetch();
      // ... process the items ...
    });
  });
}

(事实上，对于这个测试，整个项目只是在一个 .js 文件中包含上述代码)。用 meteor 启动这个程序会抛出一个错误:

/home/yaakov/Bug/.meteor/local/build/programs/server/boot.js:198
}).run();
   ^
Error: Can't call yield in a noYieldsAllowed block!
    at Function.Fiber.yield (packages/meteor/fiber_helpers.js:11)
    at Function.wait (home/yaakov/.meteor/tools/cef2bcd356/lib/node_modules/fibers/future.js:111:14)
    at Object.Future.wait (/home/yaakov/.meteor/tools/cef2bcd356/lib/node_modules/fibers/future.js:325:10)
    at new MongoConnection (packages/mongo-livedata/mongo_driver.js:196)
    at new MongoInternals.RemoteCollectionDriver (packages/mongo-livedata/remote_collection_driver.js:4)
    at Object.<anonymous> (packages/mongo-livedata/remote_collection_driver.js:44)
    at Object.defaultRemoteCollectionDriver (packages/underscore/underscore.js:750)
    at new Meteor.Collection (packages/mongo-livedata/collection.js:72)
    at app/Bug.js:4:17
    at packages/deps/deps.js:47

我做错了什么？如何在 meteor 服务器上创建响应式(Reactive)集合查询？

Answer 1

Deps 包只能在客户端工作，所以你不能在服务器端使用Deps.autorun。

要在服务器上使用类似响应式的查询，请改用observe:

var items=collection.find().observe({
    added: function (document) {
        // ...
    },
    changed: function (newDocument, oldDocument) {
        // ...
    },
    removed: function (oldDocument) {
        // ...
    }
});