如何让 Meteor 对子项目有反应，但对父项目没有反应 [英] How to make Meteor reactive on sub-items, but not parent

问题描述

我有一个想用 Meteor 构建的 Newsfeed 想法，但我在弄清楚如何使新闻提要本身保持不变时遇到了一些困难，这不是反应性的，而是更新子项目(评论、喜欢等)一更新.

我将所有内容都存储在一个集合中，如果可能，我想保持这种状态.所以集合是这样设置的:

<预><代码>[{title: '随机标题',date_created: '01/01/2001',注释:[{'message': 'Lorem ipsum', date_created: '01/01/2001'},[...]]},[...]]

所以我想做的是让新闻源无反应，这样当插入或更新新新闻时，保存新闻列表的模板不会被重新渲染.但是，如果添加、删除评论或有人喜欢新闻提要，我希望它立即在模板中更新.

我一直在想如何使用 {{#isolate}} 和 {{#constant}} 但没有成功.

这是我的客户端 JS:

Template.group_feed.feed_data = function() {var feed = Newsfeed.find({}, {排序:{updated_time:-1}，限制:10，反应性:假}).拿来();回饲料；};

我设置了 reactive: false 以便它不会更新模板，但是当评论或喜欢被更新时，这也使它成为静态的.所以我猜有一种更好的方法可以做到这一点，然后使整个集合无反应.

这是我的模板代码:

<模板名称="group_feed"><div id="feed-wrapper"><ul>{{#each feed_data}}{{>group_feed_item}}{{/每个}}

<模板名称="group_feed_item"><li><h1>{{title}}</h1><div class="评论">{{#每个评论}}<p>{{message}}</p>{{/每个}}

有没有人有实现这一目标的好方法?

解决方案

我没有测试它，但我想限制客户端的订阅是最直接的，从而减少数据传输并消除对保留的需要:

应该是这样的:

在服务器上:

Meteor.publish('tenItemsBefore',function (time) {Newsfeed.find({updated_time: {$lt time}}, {排序:{updated_time:-1}，限制:10})}

在客户端上，在响应式上下文中，例如.在 Meteor.autorun() 中:

Newsfeed.subscribe('tenItemsBefore',Session.get('lastUpdate'));

在客户端，由事件触发，例如.使用路由器包刷新:

Session.set('lastUpdate', (new Date()).getTime());

希望有所帮助，

最好的，简

I've got a Newsfeed idea that I wanted to build with Meteor, but I'm having a bit of a struggle figuring out how to make the news feed itself constant, that is not reactive, but update the sub-items (comments, likes, etc) as soon as they're updated.

I've got everything stored in a single collection, and I'd like to keep it that way if possible. So the collection is setup like this:

[
    {
        title: 'A random title',
        date_created: '01/01/2001',
        comments:
            [
                {'message': 'Lorem ipsum', date_created: '01/01/2001'},
                [...]
            ]
    },
    [...]
]

So what I'd like to do is have the newsfeed non-reactive, so that when a new news item is inserted or updated, the template holding the list of news won't get re-rendered. But if a comment is added, deleted, or someone likes the news feed, I'd want that to get updated right away in the template.

I've been trying to figure out how to use {{#isolate}} and {{#constant}} but to no prevail.

Here's my client side JS:

Template.group_feed.feed_data = function() {
    var feed = Newsfeed.find({}, {
        sort: {updated_time: -1},
        limit: 10,
        reactive: false
    }).fetch();

    return feed;
};

I set reactive: false so that it doesn't update the template, but that makes it static also when comments or likes are updated. So I'm guessing there's a better way to do this then to make the whole collection non-reactive.

Here's my template code:

<template name="group_feed">
    <div id="feed-wrapper">
        <ul>
            {{#each feed_data}}
                {{> group_feed_item}}
            {{/each}}
        </ul>
    </div>
</template>

<template name="group_feed_item">
    <li>
        <h1>{{title}}</h1>
        <div class="comments">
            {{#each comments}}
                <p>{{message}}</p>
            {{/each}}
        </div>
    </li>
</template>

Anyone got a nice way of achieving this?

解决方案

I did not test it, but I guess it would be most straightforward to limit the subscription of the client, thus reducing data transfer an eliminataing the need for the preserve:

it would be something like:

on server:

Meteor.publish('tenItemsBefore',function (time) {
  Newsfeed.find({updated_time: {$lt time}}, {
  sort: {updated_time: -1},
  limit: 10
})}

on client, in reactive context eg. in Meteor.autorun():

Newsfeed.subscribe('tenItemsBefore',Session.get('lastUpdate'));

on client, triggered by an event eg. refresh using router package:

Session.set('lastUpdate', (new Date()).getTime());

hope that helps,

best, Jan

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