我正在编写一个应用程序,它根据集合计数显示估计的等待时间。我遇到的问题是,当页面加载或刷新时,waitTime 显示,但它首先显示 0,大约一秒钟后,它会根据计数显示实际的 waitTime。我假设这与变量在从集合中获取计数时被延迟有关,因此它显示初始计数 0,然后获取实际计数并显示 waitTime?
有没有办法让它只显示加载或刷新时的确切等待时间?
js:
Template.home.helpers({
waitTime: function() {
var totalCount = Students.find().count();
var hour = totalCount/4;
if(totalCount < 4){
return 15*totalCount + " minutes"
}else if(totalCount >= 4 && totalCount%4 == 0){
return hour + " hour(s)";
}else if(totalCount >= 4 && totalCount%4 == 1){
hour = hour - .25;
return hour + " hour(s)" + " 15 minutes";
}else if(totalCount >= 4 && totalCount%4 == 2){
hour = hour - .5;
return hour + " hour(s)" + " 30 minutes";
}else if(totalCount >= 4 && totalCount%4 == 3){
hour = hour - .75;
return hour + " hour(s)" + " 45 minutes";
}
}
});
HTML:
<template name= "home">
<body>
<h2 id="insert">Approximate Wait Time: {{waitTime}}</h2>
<div class="col-lg-6 col-lg-offset-3">
<!-- Quick form from autoform package creates sign in form and populates collection with data-->
{{>quickForm id="studentForm" collection="Students" type="insert" template="bootstrap3-horizontal" label-class="col-sm-3" input-col-class="col-sm-9"}}
</div>
</body>
</template>
最佳答案
最直接的方法是在数据准备好之前不渲染 View (或至少 View 的相关部分)。两种主要方法是等待订阅准备就绪,或者等到获得所需的数据值。
后者会很困难,因为据我所知,0 是一个可能的值。所以我建议前者。
假设您的订阅与您的模板绑定(bind),您可以像这样等待订阅准备就绪:
<template name= "home">
<body>
{{#if Template.subscriptionsReady}}
<h2 id="insert">Approximate Wait Time: {{waitTime}}</h2>
<div class="col-lg-6 col-lg-offset-3">
<!-- Quick form from autoform package creates sign in form and populates collection with data-->
{{>quickForm id="studentForm" collection="Students" type="insert" template="bootstrap3-horizontal" label-class="col-sm-3" input-col-class="col-sm-9"}}
</div>
{{else}}
Loading...
{{/if}}
</body>
</template>
关于javascript - 如何延迟 meteor 中变量的显示?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/43509240/