How do I access one 'sibling' variable in a meteor template helper when I am in the context of another? - meteor

Question

How do I access one 'sibling' variable in a meteor template helper, when I am in the context of another? I want to determine whether the user that is logged in and viewing the page is the same user that posted the ride offering, so that I can hide or show the "bid" button accordingly.
For example, here is my template (html) file:
<!-- client/views/ride_offers.html -->
<template name="RideOfferPage">
<p>UserIsOwner:{{UserIsOwner}}</p>
{{#with CurrentRideOffer}}
{{> RideOffer}}
{{/with}}
</template>
<template name="RideOffer">
<div class="post">
<div class="post-content">
<p>Details, Author: {{author}}, From: {{origin}}, To: {{destination}}, between {{earliest}} and {{latest}} for {{nseats}} person(s). Asking ${{price}}.
<button type="button" class="btn btn-primary" >Bid</button><p>
<p>UserIsOwner:{{UserIsOwner}}</p>
</div>
</div>
</template>
And here is my JavaScript file:
Template.RideOfferPage.helpers({
CurrentRideOffer: function() {
return RideOffers.findOne(Session.get('CurrentOfferId'));
},
UserIsOwner: function() {
return RideOffers.find({_id: Session.get('CurrentOfferId'), userId: Meteor.userId()}).count() > 0;
}
});
In the "RideOffer" template, I am able access the variables author, origin, ..., price. But I am unable to access the boolean UserIsOwner. I am, however, able to access the boolean UserIsOwner in the "RideOfferPage" template.
Does anyone know how I can access the boolean UserIsOwner in the "RideOffer" template?
Cheers,

Answer 1

Put the userIsOwner function outside the helper as an anonymous function and then call it from both templates.
Template.RideOfferPage.helpers({
CurrentRideOffer: function() {
return RideOffers.findOne(Session.get('CurrentOfferId'));
},
UserIsOwner: checkUserIsOwner()
});
Template.RideOffer.helpers({
UserIsOwner: checkUserIsOwner()
});
checkUserIsOwner= function() {
return RideOffers.find({_id: Session.get('CurrentOfferId'), userId: Meteor.userId()}).count() > 0;
}

Answer 2

There are several ways to do what you're asking.
In your particular example you are not asking about siblings, but about parents, since the RideOfferPage template renders the RideOffer template. You can access variables in the parent data context (but not helpers) like so:
<template name="RideOffer">
<div class="post">
<div class="post-content">
<!--
other stuff
-->
<p>UserIsOwner:{{../UserIsOwner}}</p>
</div>
</div>
</template>
In other cases, you may have a template being rendered as a sibling of this one. In that case, you can't actually know what the sibling is until the template is actually on the page; however, you can find it in the rendered callback:
Template.foo.rendered = function() {
var current = this.firstNode;
var next = $(currentItem).next(); // or .prev()
if (next.length) {
nextData = Spark.getDataContext(next[0]);
}
// Do something with nextData
};
Finally, you can get the parent context of any rendered DOM element by repeatedly iterating through its parents. This isn't super efficient but I've used it in places where there is extensive drag and drop with DOMFragments moving around on the page:
Template.bar.events = {
"click .something": function(e) {
var target = e.target;
var context = Spark.getDataContext(target);
var parentContext = context;
while (parentContext === context) {
parentContext = Spark.getDataContext(target = target.parentNode);
}
// Do something with parentContext
}
};
I'm curious to know if there is a better way to do the last thing, which may potentially have to iterate through many DOM elements. In any case, you may want to check out my meteor-autocomplete package for this and other cool tricks.