I'm learning meteor to build quick website prototypes.
I'm trying to understand how to generate a set of values to populate the site templates and partials.
I have a layout.html template
<template name="layout">
<div class="container">
<header role="banner">
{{>site-header}}
</header>
<h1>This is {{siteLogo}}</h1>
<main role="main">
{{ yield }}
</main>
<footer role="contentinfo">
{{> site-footer }}
</footer>
</div>
</template>
in main.js I define the following:
Meteor.startup(function(){
Session.set('siteLogo', 'the logo');
});
Template.site-header.helpers({
siteLogo: function(){ return Session.get('siteLogo'); }
});
Template.layout.helpers({
siteLogo: function(){ return Session.get('siteLogo'); }
});
With this i can pass the value of siteLogo to layout.html.
I have a site-header.html partial
<template name="site-header">
<h1>{{siteLogo}}</h1>
</template>
I can't seem to be able to pass the value of siteLogo to the partial. Is there a way to do that?
Is it necessary to create a Session variable to pre-fill some values or can i just create a json settings list and access the value globally?
something that would go in main.js, like the yaml config file in a jekyll site:
siteSettings = [
{
siteLogo: "some brand name",
otherValue: "something else"
}
]
update
I'm a bit confused, I'm must be doing something wrong.
I've created a quick new meteor app to test this.
I have main.html
<head>
<title>handlebar-helper</title>
</head>
<body>
{{> header}}
{{> hello}}
{{> footer}}
</body>
<template name="hello">
<h1>Hello World!</h1>
{{greeting}}
<input type="button" value="Click" />
</template>
<template name="header">
<header>
<h1>{{ headline }}</h1>
<p>tagline</p>
</header>
</template>
<template name="footer">
<footer role="contentinfo">
<h1>{{ headline }}</h1>
<small>copyright</small>
</footer>
</template>
And main.js
if (Meteor.isClient) {
Template.hello.greeting = function () {
return "Welcome to handlebar-helper.";
};
Template.hello.events({
'click input' : function () {
// template data, if any, is available in 'this'
if (typeof console !== 'undefined')
console.log("You pressed the button");
}
});
Meteor.startup(function(){
Session.set('headline', 'My fancy headline');
});
Handlebars.registerHelper('headline', function(){
return Session.get('headline');
});
}
if (Meteor.isServer) {
// server code here
}
And i can't still pass the value of headline into >header of >footer
if I try to put the Session.set into the Meteor.isServer block, I get a syntax error, Session is not defined
Cheers
Do you have a Template.site-header.helpers function declared for siteLogo? If not it won't work - you can't use a helper from another template. If you need to use siteLogo in a variety of places, it's best to use a Handlebars block helper, as these can be accessed by any template.
UPDATE
The Handlebars helper would just look like this:
Handlebars.registerHelper('siteLogo', function() {
return Session.get('siteLogo');
});
However, if you've already got a siteLogo helper in the site-header Template, it suggests something else is wrong, like a typo in a template or helper name. Is there an error in the console?
UPDATE 2
If you want to use a dictionary-style structure to store reactive data, you can do something like this:
Session.set('myDict', {foo: 1, bar: 2});
Handlebars.registerHelper('myDict', function(key) {
return Session.get('myDict') ? Session.get('myDict')[key] : null;
});
And then use this in your template: {{myDict 'foo'}}. Obviously, the format above would work fine in a tempate helper as well, but it would only be accessible from within that template. The ternary operator is just to check that myDict has been initialised before it lets a template try to look up one of the keys, which is a common Meteor problem on page load.
Incidentally, if you're finding Session variables a cumbersome way to deal with reactive dictionary-like data structures, it's pretty easy to roll your own. This is the best introduction.
Related
I am trying to combine 2 beginner classes together (https://www.meteor.com/tutorials/blaze/templates & http://meteortips.com/second-meteor-tutorial/iron-router-part-1/). I have been able to complete both classes individually with no problem.
I am using Iron:Router to route to various templates. I run in to issues when I try to access a template within a template. The proper results do not get displayed on the " aostasks"page.
.js:
Router.route('aostask', {
template: 'aostask'
});
Tasks = new Mongo.Collection("tasks");
if (Meteor.isClient) {
// This code only runs on the client
Template.registerHelpers('task', function () {
return tasks.find({});
})
};
.html:
<template name= "aostask">
<head>
<title>Todo List</title>
</head>
<body>
<div class="container">
<header>
<h1>Todo List</h1>
</header>
<ul>
{{#each tasks}}
{{> task}}
{{/each}}
</ul>
</div>
</body>
</template>
<template name="task">
<li>{{text}}</li>
</template>
Result:
A page with the correct headers.However, it does not list the tasks i have in my mongo collection. Is the issue that i am using the registerHelper function incorrectly? Should i be using some other function?
Thanks in advance.
There is typo in your helper name
Template.registerHelper('tasks', function () {
return tasks.find({});
})
};
tasks not task
Your helper is registered with the same name as your template. It should be just 'task'. Template.registerHelpers should be Template.registerHelper
if (Meteor.isClient) {
// This code only runs on the client
Template.registerHelper('task', function () {
return Tasks.find({});
})
};
I'm new to both meteor and JS.
I created a meteor app like this:
cd /tmp/
meteor create hello
cd hello
In hello.html I wrote this
<body>
<h1>Welcome to Meteor!</h1>
{{> t1}}
{{> t2}}
</body>
Then I added these templates:
<template name='t1'>
<span id='t1'>hello</span>
</template>
<template name='t2'>
<span id='t2'>world</span>
</template>
Then I wrote syntax inside of hello.js to get text from the DOM:
Template.t1.onRendered( function() {
mytext = $('span#t1').html() });
According to the debugger-console in my browser,
the above syntax works okay.
The debugger tells me that mytext == 'hello'
Question: How to share the mytext value with other parts of my Meteor app?
As written, mytext is stuck inside my anonymous function.
For example how would I make this call work:
$('span#t2').html(mytext)
??
You'll want to reactively watch your variable. An easy out-of-the-box solution for this is to use the Session variable. You can do it pretty easily like so:
Template.t1.onRendered( function() {
Session.set('mytext', $('span#t1').html());
});
Then in your second template, define and reference helper that returns that variable:
<!--html-->
<template name='t2'>
<span id='t2'>{{getMyText}}</span>
</template>
//js
Template.t2.helpers({
getMyText: function() { return Session.get('mytext'); }
});
The Session variable is reactive, so when the first template renders and sets the value of Session.mytext, the helper's result will be invalidated and the second template will update.
Here's what I want, a custom block helper that can act like a template, monitoring for it's own events etc. The html would look like this:
{{#expandable}}
{{#if expanded}}
Content!!!
<div id="toggle-area"></div>
{{else}}
<div id="toggle-area"></div>
{{/if}}
{{/expandable}}
And here's some javascript I have put together. This would work if I just declared the above as a template, but I want it to apply to whatever input is given to that expandable block helper.
Template.expandableView.created = function() {
this.data._isExpanded = false;
this.data._isExpandedDep = new Deps.Dependency();
}
Template.expandableView.events({
'click .toggle-area': function(e, t) {
t.data._isExpanded = !t.data._isExpanded;
t.data._isExpandedDep.changed();
}
});
Template.expandableView.expanded = function() {
this._isExpandedDep.depend();
return this._isExpanded;
};
I know I can declare block helpers with syntax like this:
Handlebars.registerHelper('expandable', function() {
var contents = options.fn(this);
// boring block helper that unconditionally returns the content
return contents;
});
But that wouldn't have the template behavior.
Thanks in advance! This might not be really possible with the current Meteor implementation.
Update
The implementation given by HubertOG is super cool, but the expanded helper isn't accessible from within the content below:
<template name="expandableView">
{{expanded}} <!-- this works correctly -->
{{content}}
</template>
<!-- in an appropriate 'home' template -->
{{#expandable}}
{{expanded}} <!-- this doesn't work correctly. Expanded is undefined. -->
<button class="toggle-thing">Toggle</button>
{{#if expanded}}
Content is showing!
{{else}}
Nope....
{{/if}}
{{/expandable}}
In the actual block helper, expanded is undefined, since the real thing is a level up in the context. I tried things like {{../expanded}} and {{this.expanded}}, but to no avail.
Strangely, the event handler is correctly wired up.... it fires when I click that button, but the expanded helper is simply never called from within the content, so even console.log() calls are never fired.
Meteor's new Blaze template engine solves this problem quite nicely.
Here's an excerpt from the Blaze docs showing how they can be used.
Definition:
<template name="ifEven">
{{#if isEven value}}
{{> UI.contentBlock}}
{{else}}
{{> UI.elseBlock}}
{{/if}}
</template>
Template.ifEven.isEven = function (value) {
return (value % 2) === 0;
}
Usage:
{{#ifEven value=2}}
2 is even
{{else}}
2 is odd
{{/ifEven}}
You can achieve this by making a helper that returns a template, and passing the helper options as a data to that template.
First, make your helper template:
<template name="helperTemplate">
<div class="this-is-a-helper-box">
<p>I'm a helper!</p>
{{helperContents}}
</div>
</template>
This will work as a typical template, i.e. it can respond to events:
Template.helperTemplate.events({
'click .click-me': function(e, t) {
alert('CLICK!');
},
});
Finally, make a helper that will return this template.
Handlebars.registerHelper('blockHelper', function(options) {
return new Handlebars.SafeString(Template.helperTemplate({
helperContents: new Handlebars.SafeString(options.fn(this)),
}));
});
The helper options are passed as a helperContents param inside the template data. We used that param in the template to display the contents. Notice also that you need to wrap the returned HTML code in Handlebars.SafeString, both in the case of the template helper and its data.
Then you can use it just as intended:
<template name="example">
{{#blockHelper}}
Blah blah blah
<div class="click-me">CLICK</div>
{{/blockHelper}}
</template>
I'm running Meteor 0.5.7, and trying to display a bootstrap alert message when user clicks submit.
client.js
Handlebars.registerHelper('isSuccessful',function(input){
return Session.get("success");
});
Template.form.events({
'click .submit' : function (event, template) {
if (condition) {
Session.set("success", true);
// hide warning, show success
$('#valid_form').show();
$('#invalid_form').hide();
} else {
Session.set("success", false);
// hide success, show warning
$('#valid_form').hide();
$('#invalid_form').show();
}
}
});
Template.form.rendered = function () { $('.alert').hide();};
page.html
<body>
{{> page}}
</body>
<template name='page'>
{{> form}}
</template>
<template name='form'>
<!-- Show Alerts Above Form -->
<div class="alert alert-success" id="valid_form">..</div>
<div class="alert" id="invalid_form">..</div>
{{#if isSuccessful}}
<div>SHOW CONFIRMATION PAGE</div>
{{else}}
<div>SHOW INPUT FIELDS</div>
{{/if}}
<div>
</template>
When the user INITIALLY clicks submit and the condition is not met, they have to click submit again in order to get the warning message. All other times the logic works.
I've looked at this - How does Meteor's reactivity work behind the scenes?, and re-read the Meteor docs on reactive programming parts, but something is still amiss.
Shouldn't the else statement in the client default to a session variable of success == false, and the handlebar template pick it up immediately in the {{else}} block? SLightly confused. Thanks,
The answer to my question appears to be that changing return Session.get("success") to return Session.equals("success",true) in the handlebar registered helper did the trick. From what I'm reading, it has less "invalidations"? - not sure what that's suppose to mean atm, but it's a start!
If your purpose is to hide/show the relevant alerts on a condition, you can just do this instead:
client.js
Template.form.rendered = function() {
// hide all alerts when elements are rendered
$('.alert').alert('hide');
}
Template.form.events({
'click .submit' : function (event, template) {
if (condition) {
// hide warning, show success
$('#valid_form').alert();
$('#invalid_form').alert('hide');
} else {
// hide success, show warning
$('#valid_form').alert('hide');
$('#invalid_form').alert();
}
}
});
page.html:
<body>
{{> page}}
</body>
<template name='page'>
{{> form}}
</template>
<template name='form'>
<div class="alert alert-success" id="valid_form">..</div>
<div class="alert" id="invalid_form">..</div>
</template>
I'm getting client side errors(console.log ones) but my app works(I can add users)
The error is the following:
Uncaught TypeError: Cannot read property '_liveui' of null
The project is in my repo:
https://github.com/thiagofm/statusfyit
What is happening?
Meteor has updated its API a bunch since this question was asked, so the original code no longer runs directly.
Using jQuery.html to insert the results of rendering a template is not the normal approach. It is better to use the handlebars template include functionality.
For example, replace:
$().ready(function(){
hello = Meteor.ui.render(function(){
return Template.hello();
});
$('body').html(hello);
});
With:
<body>
{{> hello}}
</body>
To render different things depending on the state of the application, use the 'Session' object to conditionalize includes. For example:
<template name="foo">
{{#if showNewUserDialog}}
{{> newUserDialog}}
{{else}}
other stuff
{{/if}}
</template>
<template name="newUserDialog">
some stuff
</template>
and
Template.foo.showNewUserDialog = function () {
return Session.get('showNewUserDialog');
};
Template.other.events({
'click #new_user': function () {
Session.set('showNewUserDialog', true);
}
});