How to make a session variable reactive? - meteor

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>

Related

Meteor stopped running template `rendered` functions

Im trying to run some jquery code after the template renders. But it's not working. When I run the code in the console manually, it works. Here's the js :
Template.PanelLayout.helpers({
restricted: function() {
return !Meteor.user();
},
authInProcess: function() {
return Meteor.loggingIn();
},
canShow: function() {
return !!Meteor.user();
}
});
Template.PanelLayout.rendered = function() {
$(document).ready(function() { // This is the code I want to run
$(".button-collapse").sideNav();
$('.collapsible').collapsible();
});
}
Template code :
<template name="PanelLayout">
{{#if restricted}}
{{> NotFound}}
{{else}}
{{#if authInProcess}}
{{> spinner}}
{{else}}
{{#if canShow}}
<header>
{{> PanelMainNav}}
</header>
<main id="panel-content">
{{> Template.dynamic template=content }}
</main>
{{/if}}
{{/if}}
{{/if}}
</template>
Im not sure but I think it's because I have added the if else statements to load the content only when the user is logged in? How can I fix this?
Probably it's because rendered function is called after document is ready, therefore your hook document.ready won't work, you should remove it, so it will look like this(also rendered function is deprecated, use onRendered instead):
Template.PanelLayout.onRendered(function() {
$(".button-collapse").sideNav();
$('.collapsible').collapsible();
});

How to append Template Data to another Template based on Button Click in Meteor JS?

One template have button and another template have contains one text field.When ever button clicked that text filed append to the button template at the same time not remove the previous text fields that means the button clicked in 4 times 4 text fields add to the button template.
See the following code :
HTML Code :
<head>
<title>hello</title>
</head>
<body>
<h1>Welcome to Meteor!</h1>
{{> hello}}
</body>
<template name="hello">
Add Text Fields here :
<button>add another text box</button>
</template>
<template name="home">
<input type="text" id="name" />
</template>
JS Code :
if (Meteor.isClient) {
Template.hello.events({
'click button': function () {
//Here to write append logic
}
});
}
I didn't get any idea about this.So please suggest me what to do for this?
Use a client side only collection. Clicking adds a new record. Then in home template you loop on this. new Meteor.Collection(null) the null will tell it that it is local only and won't actually create the collection in the MongoDB.
if (Meteor.isClient) {
var buttonClicks = new Meteor.Collection(null),
clickCounter = 0;
Template.hello.events({
'click button': function () {
buttonClicks.insert({click: clickCounter++});
}
});
Template.home.helpers({
clicks: function () {
return buttonClicks.find({});
}
});
}
<template name="home">
{{#each clicks}}
<input type="text" id="name_{{click}}" />
{{/each}}
</template>

passing values to meteor partials

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.

Content wrapped in currentUser re-rendering when user updated

I'm using Meteor and having an issue where my content is being re-rendered when I don't want it to.
I have my main content wrapped in a currentUser if statement which I feel is fairly standard.
{{#if currentUser}}
{{> content}}
{{/if}}
The problem with this is my content template is being re-rendered when I update my user object. Is there any way around this? I don't reference users anywhere inside the content template.
Thank you!
Here's a sample app to replicate my problem:
HTML
<head>
<title>Render Test</title>
</head>
<body>
{{loginButtons}}
{{> userUpdate}}
{{#if currentUser}}
{{> content}}
{{/if}}
</body>
<template name="userUpdate">
<p>
<input id="updateUser" type="button" value="Update User Value" />
User last update: <span id="lastUpdated">{{lastUpdated}}</span>
</p>
</template>
<template name="content">
<p>Render count: <span id="renderCount"></span></p>
</template>
JavaScript
if (Meteor.isClient) {
Meteor.startup(function() {
Session.set("contentRenderedCount", 0);
});
Template.content.rendered = function() {
var renderCount = Session.get("contentRenderedCount") + 1;
Session.set("contentRenderedCount", renderCount);
document.getElementById("renderCount").innerText = renderCount;
};
Template.userUpdate.events = {
"click #updateUser": function() {
Meteor.users.update({_id: Meteor.userId()}, {$set: {lastActive: new Date()}});
}
};
Template.userUpdate.lastUpdated = function() {
return Meteor.user().lastActive;
};
}
if (Meteor.isServer) {
Meteor.users.allow({
'update': function () {
return true;
}
});
}
Update:
I should've explained this example a little. After creating a user, clicking the Update User Value button, causes the render count to increment. This is because it's wrapped in a {{#if currentUser}}. If this is if is removed, you'll notice the render count remains at 1.
Also, you'll need to add the accounts-ui and accounts-password packages to your project.
Meteor will re-render any template containing reactive variables that are altered. In your case the {{currentUser}} is Meteor.user() which is an object containing the user's data. When you update the users profile, the object changes and it tells meteor to re-calculate everything reactive involving the object.
We could alter the reactivity a bit so it only reacts to changes in whether the user logs in/out and not anything within the object itself:
Meteor.autorun(function() {
Session.set("meteor_loggedin",!!Meteor.user());
});
Handlebars.registerHelper('session',function(input){
return Session.get(input);
});
Your html
{{#if session "meteor_loggedin"}}
{{> content}}
{{/if}}

Template reuse in meteor

I'm trying to reuse some control elements in my Meteor app. I'd like the following two templates to toggle visibility and submission of different forms.
<template name='addControl'>
<img class='add' src='/images/icon-plus.png' />
</template>
<template name='okCancelControl'>
<img class='submit' src='/images/icon-submit.png' />
<img class='cancel' src='/images/icon-cancel.png' />
</template>
I'll call these templates in another:
<template name='insectForm'>
{{#if editing}}
<!-- form elements -->
{{> okCancelControl}}
{{else}}
{{> addControl}}
{{/if}}
</template>
editing is a Session boolean.
What's a good way to wire up the controls to show, hide and "submit" the form?
The main problem is finding the addInsect template (where the data is) from the control templates (where the "submit" event fires). Here's what I did:
First, the controls:
<template name='addControl'>
<section class='controls'>
<span class="add icon-plus"></span>
</section>
</template>
<template name='okCancelControl'>
<section class='controls'>
<span class="submit icon-publish"></span>
<span class="cancel icon-cancel"></span>
</section>
</template>
Now the javascripts. They simply invoke a callback when clicked.
Template.addControl.events({
'click .add': function(event, template) {
if (this.add != null) {
this.add(event, template);
}
}
});
Template.okCancelControl.events({
'click .cancel': function(event, template) {
if (this.cancel != null) {
this.cancel(event, template);
}
},
'click .submit': function(event, template) {
if (this.submit != null) {
this.submit(event, template);
}
}
});
I then connected the callbacks using handlebars' #with block helper.
<template name='addInsect'>
{{#with controlCallbacks}}
{{#if addingInsect}}
<section class='form'>
{{> insectErrors}}
<label for='scientificName'>Scientific Name <input type='text' id='scientificName' /></label>
<label for='commonName'>Common Name <input type='text' id='commonName' /></label>
{{> okCancelControl}}
</section>
{{else}}
{{> addControl}}
{{/if}}
{{/with}}
</template>
And the corresponding javascript that creates the callbacks relevant to this form.
Session.set('addingInsect', false);
Template.addInsect.controlCallbacks = {
add: function() {
Session.set('addingInsect', true);
Session.set('addInsectErrors', null);
},
cancel: function() {
Session.set('addingInsect', false);
Session.set('addInsectErrors', null);
},
submit: function() {
var attrs, errors;
attrs = {
commonName: DomUtils.find(document, 'input#commonName').value,
scientificName: DomUtils.find(document, 'input#scientificName').value
};
errors = Insects.validate(attrs);
Session.set('addInsectErrors', errors);
if (errors == null) {
Session.set('addingInsect', false);
Meteor.call('newInsect', attrs);
}
}
};
Template.addInsect.addingInsect = function() {
Session.get('addingInsect');
};
Template.addInsect.events = {
'keyup #scientificName, keyup #commonName': function(event, template) {
if (event.which === 13) {
this.submit();
}
}
};
In the submit callback I had to use DomUtils.find rather than template.find because template is an instance of okCancelControl, not addInsect.
You can use Session for this. You Just need a template helper that returns a boolean flag that indicates whether you are editing the form fields. And manipulate the DOM based on the Session value set by this template helper.
Assume you have one text input, now when you are entering text in it, set the Session flag as true. This will trigger the helper to return true flag, Based on that, one of your two templates will be rendered in the DOM.
The isEditing is the helper that triggers whenever you change the Session value.
This helper function is the main part here, it returns true/false based on the session value you have set.
Template.insectForm.isEditing = function(){
if(Session.get('isEditing')){
return true;
}
else{
return false;
}
}
Remember to set the Session to false at the start-up as:
$(document).ready(function(){
Session.set('isEditing', false);
})
This will render the default add template in the html, Now when you click on ADD, you need to display another template, for that, set Session to true as:
'click .add' : function(){
Session.set('isEditing', true);
}
Accordingly when you click on CANCEL, set the session to false, this will make the isEditing to return false and the default add template will be displayed.
So your complete html will look something like this:
<template name='insectForm'>
{{#if isEditing}}
<!-- form elements -->
<input type="text" id="text" value="">
{{> okCancelControl}}
{{else}}
{{> addControl}}
{{/if}}
</template>
<template name='addControl'>
<img class='add' src='/images/icon-plus.png' />
</template>
<template name='okCancelControl'>
<img class='submit' src='/images/icon-submit.png' />
<img class='cancel' src='/images/icon-cancel.png' />
</template>
[UPDATE]
To get the instance of the template, you'll need to pass the additional parameter in the event handler that represents the template.
So update your event handler as:
Template.insectForm.events = {
'click .submit' : function(event, template){
//your event handling code
}
}
The parameter template is the instance of the template from which the event originates.
Note that, although the event fires form the image that is inside the okCancelControl template, the parameter will still contain the instance of the insectForm template. This is because we are calling the event handler as Template.insectForm.events = {} .
Also see this answer for template instances.

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