Iron Router数据触发3次 [英] Iron Router data fires 3 times

问题描述

我在Router.Config上使用路由模板设置了此路由

I have this route set up with a loding template on Router.Config

Router.onBeforeAction('loading');
this.route('clients', {
    path: '/clients',
    template: 'clientsAll',
    waitOn: function () {
        return Meteor.subscribe('clientsAll');
    },
    data: function () {
        if (this.ready()) {
            console.log("Data");
            return Clients.find().fetch();
        }
    }
});

一切正常，在呈现模板之前显示加载模板，但在日志上显示数据被触发两次.

Everything works fine it displays the loading template before rendering the template, but on the log it shows data being fired twice.

推荐答案

这是正常现象，像大多数路由方法一样，data也在反应式计算中运行.

This is a normal behavior, data like most route methods is run inside a reactive computation.

在您的data方法中，您依赖于this.ready()，它恰好是反应性数据源(它返回由waitOn返回的等待列表的状态).

In your data method you depend on this.ready() which happens to be a reactive data source (it returns the state of the wait list returned by waitOn).

所以基本上这就是发生的事情:

So basically this is what is going on :

• 您的数据方法被声明为一种计算，并且最初在this.ready()返回false的情况下运行.
• 您等待的订阅将在将来的某个时间准备好，因此this.ready()现在返回true，并且您的data方法将重新运行.

• your data method is declared as a computation and initially runs with this.ready() returning false.
• the subscription you wait on becomes ready some time in the future so this.ready() now returns true and your data method is rerun.

这不是问题，因为data方法通常不占用大量计算资源(它们仅返回一些在客户端本地可用的数据).

This is not a problem because data methods are usually not computational heavy (they just return some data that is available locally on the client).

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