问题描述
如果我返回find与fetch的结果，在流星模板帮助器函数内部，性能，重渲染次数或其他任何内容是否存在差异?
Inside a meteor template helper function, is there any difference in performance, number of re-renders, or anything else if I return the result of a find vs a fetch?
例如，查找方法:
Template.players.topScorers = function () {
return Users.find({score: {$gt: 100}}, {sort: {score: -1}});
};
或添加提取:
Template.players.topScorers = function () {
return Users.find({score: {$gt: 100}}, {sort: {score: -1}}).fetch();
};
仅查找"方法是文档中的当前方法，但是我看到很多其他人使用fetch.
The find-only approach is what is currently in the docs, but I’ve seen lots of other people using fetch.
推荐答案
是的.
通过使用访存，您可以在现场注册对整个查询结果集的依赖.通过使用find以及以后使用{{#each}}进行迭代，将在每个文档上分别注册一个依赖项.因此，当一个文档更改时，仅重新渲染相关代码.使用fetch时，更改结果集中的任何文档都会重新呈现使用fetch的整个范围.
By using fetch you register a dependency on the entire query result set on the spot. By using find and later on iterating using {{#each}} a dependency is registered on every document separately. So when one document changes, only the relevant code is re-rendered. When using fetch, changing any document in the result-set would re-render the entire scope in which you used fetch.
对于较小的结果集，没有任何区别.对于频繁更改的较大集合，它可能会减慢计算速度并导致不良的视觉伪像.
For small result-sets it doesn't make any difference. For larger sets with frequent changes it could slow down computation and cause undesired visual artefacts.
我写了帖子，帮助您理解它(虽然它不能直接回答您的问题)
I wrote a post which may help you understand it (it doesn't answer your question directly though)
这篇关于流星使用获取还是在模板帮助器函数中查找?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！