I am using a helper inside another helper. I am trying to pass a value ‘post_id’, that i am getting dynamically from ‘show_post’ helper.I want to pass it and then use it inside the query that is returning a set of result back to helper. for some reason , app is crashing. Can someone guide me through this.
{{#each show_post}}
{{posttext}}
{{postedBy}}
{{#each show_comment({{post_id}}) }}
//<--- i am passing the value to helper like this.
<span> <p>{{postedBy}}: <h5>{{commenttext}}</h5>{{createdAt}}</p></span>
{{/each}}
{{/each}}
Template.display_block.helpers({
show_post(){
return PostComment.find({parent: 0},{sort: {createdAt: -1}});
}
});
Template.display_block.helpers({
show_comment(e){
var t1 = e;
var now = PostComment.find({post_id:{$regex:new RegExp(’^’ + t1)}});
return now;
}
});
The first helper generates a array(Mongo Db result).I want to use this array’s elements(that are dynamic) in next helper. So i want to use a variable that can hold the value of array element of first helper and then pass it to next helper. In second helper, i want to pass this variable and use this variable to sort a result in Mongo query. I am new to this so i am unable to understand how this instance
Firstly you don't need to wrap helper arguments in double curly braces or parens.
{{#each show_comment post_id}}
Will do what you need.
You're also making life a bit more complicated for yourself than necessary. You can use the current data context through this in your code. Also unclear why you're using a regex unless you're concatenating something to the post _id.
This allows you to simplify down to:
html:
{{#each show_post}}
{{posttext}}
{{postedBy}}
{{#each show_comment}}
<span><p>{{postedBy}}: <h5>{{commenttext}}</h5>{{createdAt}}</p></span>
{{/each}}
{{/each}}
js:
Template.display_block.helpers({
show_comment(){
return PostComment.find({post_id: this._id);
}
});
Related
In my js file, I pass a JSON object with two keys - {'tests': tests, 'isComplete': isComplete}
In my handlebars file, I want to display the tests object based on each test status. At the same time, there's another condition for which I added a helper named 'isRequired' that I want to check the test against only if isComplete is not true.
{{#if isComplete}}
{{#each tests}}
{{#isRequired this}}
// display data
{{/isRequired}}
{{/each}}
{{else}}
{{#each tests}}
// display data
{{/each}}{{/if}}
This code has the duplicate code to display data. I'm still learning handlebars and not sure how to eliminate this redundant code block. Can you help me how I can refactor this? Thank you!
I would probably solve this by adding an isComplete parameter to your isRequired helper. You have not provided the code for your helper, but I imagine it would end up looking something like this:
Handlebars.registerHelper('isRequired', function (context, isComplete, options) {
if (!isComplete) { return options.fn(context); }
/* rest of isRequired implementation here */
});
Your template would then be updated as follows:
{{#each tests}}
{{#isRequired this ../isComplete}}
// display data
{{/isRequired}}
{{/each}}
Note that this implementation applies the isRequired logic only if isComplete is true. This is the same rules as exist in your template code sample. However, these rules appear to contradict the text of your question, which specifies that isRequired should be applied "only if isComplete is not true". If these are the requirements we must meet, we need only remove the not operator from our new guard clause:
if (isComplete) { return options.fn(context); }
Let's say I have the following Blaze template helper that fetches some objects from a collection:
PackageInCart: function() {
PackageIds = Carts.findOne({SessionId: SessionID}).Packages;
var PackageObjects = Packages.find({ _id: { $in : PackageIds } } ).fetch();
return PackageObjects;
},
The PackageObjects variable contains objects that have a 'priceperday' property with a certain price value. In the Blaze template, I can easily print this value using:
{{#each PackageInCart}}
<div class="price">{{priceperday}}</div>
{{/each}}
However, what if I want to modify the 'priceperday' value from the Helper function before it gets printed in the template? What would be the correct way to do this?
One solution that came to mind was to make a for loop that iterates over the objects and does something like Object.defineProperty() to change the priceperday property into the new value.
I want to know if there's an easier or quicker way using Blaze methods to modify the object property that gets printed with the curly braces.
If you want to do this using blaze you could do this using another helper.
weeklyPrice: function(priceperday){
return priceperday * 7;
}
Which would be called like this
{{#each PackageInCart}}
<div class="price">{{weeklyPrice priceperday}}</div>
{{/each}}
More info about spacebars helper arguments in the docs
So I am trying use a helper as an argument of another helper in Spacebars. In the example below, 'getResultInfo' is a helper that gets data specific to the arguments passed, and 'formatResult' is a helper that formats its result and the results of other helpers.
<template name="example">
{{#each collectionResults}}
Label: {{formatResult getResultInfo this._id 'text'}}
{{/each}}
</template>
The issue I'm having is that Spacebars thinks that the arguments for 'getResultInfo' are the just second and third arguments for 'formatResult'. I'd really like to keep the helper's functions separate (ie. not having to format the result at the end of the 'getResultInfo' and every other helper that I have). Is there any alternate syntax or method of doing what I'm trying to achieve?
I think that you cannot chain two helpers with parameters on the second one like you did. Subsequent parameters will still be interpreted as parameters from the first helper.
I see two ways for solving this problem:
1) you could get rid of the parameters and use the data context provided by each.
each bind the data context to this so in getResultInfo you could just use this._id directly. But you have to remember that you need this data context each time you use this helper. And this pose a problem with the 'text' parameter which does not depend from the data context.
2) you could create a function corresponding to your getResultInfo helper and use it directly in the formatResult helper like this:
getResultHelper = function(id, text) {
//do what you want
};
//bind the function to your getResultInfo (example with a global helper)
Template.registerHelper('getResultInfo', getResultHelper);
//use the function in your template helper
Template.example.helpers({
formatResult: function(format) {
return getResultHelper(this._id, format);
}
});
//and finally your template
<template name="example">
{{#each collectionResults}}
Label: {{formatResult 'text'}}
{{/each}}
</template>
FYI, this is now possible in Meteor 1.2, via Spacebars sub expressions in Blaze.
<template name="example">
{{#each collectionResults}}
Label: {{formatResult (getResultInfo this._id 'text')}}
{{/each}}
</template>
I'm trying to write a custom iterator in spacebars (I'm using meteor 1.1.3). The iterator is to be a sequential for loop (basically to replace my usage of #each when needed since I believe #each is not guaranteed to be sequential in its iteration).
I have tried the following:
In lib -
UI.registerHelper 'sequentialFor', () ->
ret = ""
for i in [0...#.length]
id = #[i]
ret = ret + Template.noop
ret
noop.html -
<template name="noop">
{{> UI.contentBlock this}}
<template>
main.html -
{{#sequentialFor ids}}
<div id="wow-{{this}}">stuff</div>
{{/sequentialFor}}
ids in the above is an array of strings passed from one of main's template helpers.
Right now it complains the the return from my UI helper is [object Object] [object Object].
For sanity's sake I know that if I replace my UI helper with:
UI.registerHelper 'sequentialFor', () ->
//ret = ""
//for i in [0...#.length]
// id = #[i]
// ret = ret + template
id = #[0]
Template.noop
I get that the div in my main.html shows up with the appropriate id as a part of its id attribute as desired. However, I can't seem to make the for loop work.
I can't simply return the div in main.html directly from the helper because I have a lot of divs that I need to wrap with my new iterator, each of which has very different attributes.
I guess the simple question is, how do I define my own block iterator (akin to #each) in spacebars?
The more difficult question may be, what is wrong with my approach above?
I have considered a wide array of resources but have only the found the following to be very helpful:
How to pass an object from to a block helper back to the block in meteor blaze?
https://github.com/meteor/meteor/wiki/Using-Blaze
https://github.com/meteor/meteor/blob/devel/packages/spacebars/README.md
Iterating over basic “for” loop using Handlebars.js
NOTE I'm using coffeescript
I managed to get a custom iterator using a recursive technique similar to what you might use in Haskell or Lisp:
<body>
{{#countdown n=5}}
<p>item {{this}}</p>
{{/countdown}}
</body>
<template name="countdown">
{{#if positive}}
{{> Template.contentBlock n}}
{{#countdown n=nMinusOne}}
{{> Template.contentBlock this}}
{{/countdown}}
{{/if}}
</template>
Template.countdown.helpers({
positive: function () {return this.n > 0;},
nMinusOne: function () {return this.n - 1;}
});
See meteorpad.
The performance is probably far worse than the usual {{#each}}.
It appears to me that you want to create a <div> for each of an array of IDs (correct me if I'm wrong). This is how I would go about it, no custom iterator necessary:
Template.registerHelper('ids', function(arrayWithIds) {
if (!arrayWithIds) return [];
// do some sorting or whatever with arrayWithIds, for example:
var arrayOfIds = _.map(arrayWithIds, function(obj) {
return obj._id;
});
return arrayOfIds;
});
Then in main.html:
{{#each ids someDataSetWithIds}}
// `someDataSetWithIds` is the helper's parameter
// `this` in each case is an ID
<div id="wow-{{this}}"></div>
{{/each}}
If your helper returns an object, you would use this._id in the template, instead. Did I misunderstand what you're trying to achieve?
Is there any way to get the object of the current iteration in Handlebars?
code:
<script id="HandleBarTemplate1" type="text/x-handlebars-template">
{{#each objArr}}
<img src="{{objField1}}"/>
<strong>Name:</strong> {{objField2}}
<input type="button" onclick="processObject({{.}});"/>
{{/each}}
</script>
I've mentioned processObject({{.}}) That is incorrect. That's where I need a replacement/Solution.Hope you get what I'm tryin' to say.
The contents of objArr might look like
var objArr = [{objField1:"smith.jpg",objField2:"Smith"},{objField1:"jane.jpg",objField2:"Jane"},...]
Template compilation code is:
var source = document.getElementById("HandleBarTemplate1").innerHTML;
var compiledTemplate = Handlebars.compile(source);
var html = compiledTemplate({objArr:objArr});
If I could get the reference to the Object, then It's so easy to process the data. Rather than passing a field to the function and searching through entire array to get the required object and then process it.
I Prefer a solution without a custom block helper/custom expression helper but if none exists, I'd rather go for a custom block helper. Any solution without searching through the entire array is welcome!
I would suggest a different route.
Knowing that you already have a reference to objArr, make a global or name-spaced variable pointing to it.
For example: window.objArr = objArr;
Create your click handler that does whatever you wish:
function processObject(key){
}
call that with your key inside your template:
< script id="HandleBarTemplate1" type="text/x-handlebars-template">
{{#each objArr}}
<img src="{{objField1}}"/>
<strong>Name:</strong> {{objField2}}
<input type="button" onclick="processObject({{objField2}});"/>
{{/each}}
</script>
Other alternatives:
Customer Handler.
Other alternatives:
If you can't create a reference to objArray, you might could store the properties of the object within data- attributes if you're using html5. processObject could then retrieve them.
I do this with a Handlebars helper and an array of context objects.
Somewhere we have an array of context objects, which will store a reference to each context object we need to reference:
var ContextObjects = [];
We need to register a Handlebars helper function that stores the current context object in the array for us when we place "{{obj}}" in the template. The helper returns the index of the object in the array, which is what gets rendered:
// Must be function and not lambda to preserve the correct 'this'
Handlebars.registerHelper("obj", function ()
{
var contextObject = this; // the current context object
var index = ContextObjects.indexOf(contextObject);
if (index < 0)
{
index = ContextObjects.length;
ContextObjects[index] = contextObject;
}
return index;
});
Next we need a function to retrieve the object from the index on the element:
// Get the context object for the current event (e.g. click or context).
function GetContextObject(event)
{
var $e = $(event.currentTarget);
var index = $e.attr("data-obj");
return ContextObjects[index];
}
We tie them together in the template something like this:
{{#each Items}}
<div data-obj="{{obj}}" onclick="DoSomething(GetContextObject(event));">...</div>
{{/each}}
Which may render something like this:
<div data-obj="0" onclick="DoSomething(GetContextObject(event));">...</div>
<div data-obj="1" onclick="DoSomething(GetContextObject(event));">...</div>
<div data-obj="2" onclick="DoSomething(GetContextObject(event));">...</div>
...