[英]How Do I Create Meteor Template Helper to Check Equality?
I am making a chat web app. 我正在制作一个聊天网络应用程序。 people can login with facebook and talk (insert message into mongoDB). 人们可以使用Facebook登录并交谈(将消息插入mongoDB)。
showing the text is simple: javascript: 显示文字很简单:javascript:
messages: function () {
return Messages.find({}, {sort: {createdAt: 1}});
}
each message has these attributes: 每条消息具有以下属性:
text: text,
createdAt: new Date(), // current time
owner: Meteor.userId(), // _id of logged in user
username: Meteor.user().profile.name
It works fine, but I want to "style the message differently" depending on whether the message's owner is equal to currentUser (ie whether it's my message or others message) 它工作正常,但是我想根据消息的所有者是否等于currentUser(即,是我的消息还是其他消息)来“对消息进行样式不同”
For example, I want my message to be float:right and others message to be float:left 例如,我希望我的消息是float:right,而其他消息是float:left
I am thinking the code probably looks something like this: 我认为代码可能看起来像这样:
{{#if mymsg}}
<div class="msgdiv_my">
<span class="message">{{text}}</span>
</div>
{{else}}
<div class="msgdiv">
<span class="message">{{text}}</span>
</div>
{{/if}}
Where and how to write the mymsg function (which should return True if the message.owner == currentUser
, and false otherwise) 在哪里以及如何编写mymsg函数(如果message.owner == currentUser
,则应返回True,否则应返回false)
You would usually write those checks in a template helper, like this: 通常,您将在模板帮助程序中编写这些检查,如下所示:
Template.myTemplate.helpers({
ownDocument: function (doc) {
return doc.owner === Meteor.userId();
}
});
Then in myTemplate
, call your helper like this: 然后在myTemplate
,像这样调用您的助手:
<template name="myTemplate">
{{#if ownDocument text}}
<div class="msgdiv_my">
<span class="message">{{text}}</span>
</div>
{{else}}
<div class="msgdiv">
<span class="message">{{text}}</span>
</div>
{{/if}}
</template>
Although you may want to implement a global "equals" helper to your meteor app's client, as it sadly is not built in Meteor Spacebars yet: 尽管您可能想为流星应用程序的客户端实现一个全局的“等于”助手,但遗憾的是它尚未内置在Meteor Spacebars中:
Template.registerHelper('equals',
function(v1, v2) {
return (v1 === v2);
}
);
This way, you would call: 这样,您将调用:
{{#if equals text.owner currentUser._id}}
And get the same result. 并得到相同的结果。
KyleMit wrote a lengthy answer for all your equality check needs in Meteor. KyleMit为您在Meteor中的所有平等检查需求写了一个冗长的答案 。
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