在meteor app中从服务器获取客户端的最新数据

I have created a mongoDB collection through server code in meteor:

我通过meteor中的服务器代码创建了一个mongoDB集合:

//Server
Restaurants = new Mongo.Collection('restaurants')   
if (Meteor.isServer) {
    //This code only runs on the server
    Meteor.publish('restaurants', function () {
    return Restaurants.find();
  }); 
}

I am trying to fetch latest data on client side every time when the data changes in the database.

每次数据库中的数据发生变化时,我都会尝试在客户端获取最新数据。

This is my client side code:

这是我的客户端代码:

//Client
Restaurants = new Mongo.Collection('restaurants');
var myData = "";

if (Meteor.isClient) {

    Meteor.subscribe('restaurants');        
    myData = Restaurants.find();
};  

Thanking you!

1 个解决方案

#1

For completeness, here's a quick revised example using your code that shows how Tracker works.

为了完整起见,这里有一个快速修改的示例,使用您的代码显示Tracker的工作原理。

Restaurants = new Mongo.Collection('restaurants')

if (Meteor.isClient) {
  Meteor.subscribe('restaurants');
  Tracker.autorun(() => {
    const restaurant = Restaurants.findOne();
    console.log(restaurant);
  });
};

if (Meteor.isServer) {
  Meteor.publish('restaurants', function restaurants() {
    return Restaurants.find();
  });

  Meteor.startup(() => {
    if (Restaurants.find().count() === 0) {
      Restaurants.insert({
        name: 'McDonalds',
      });
    }
  });
}

The above will first log undefined to your console since when Restaurants.findOne is first called, no restaurant data has been pushed to the client yet. By wrapping your find in a Tracker.autorun, when restaurant data is pushed to the client, your find will re-run, and the loaded restaurant will be logged to the console. So your console output will look like:

以上将首先将undefined记录到您的控制台,因为首次调用Restaurants.findOne时,尚未将任何餐馆数据推送到客户端。通过将您的查找包装在Tracker.autorun中,当餐馆数据被推送到客户端时,您的查找将重新运行,并且已加载的餐馆将被记录到控制台。所以你的控制台输出看起来像:

undefined
Object {_id: "HAJpQxfq59KPmTwDA", name: "McDonalds"}