Re-render Blaze template on text change - meteor

I have a Meteor Blaze Template based on autoform.
<template name="patientForm">
<div class='mdl-cell mdl-cell--12-col'>
{{#autoForm id="insertUpdatePatientForm" collection="Patients" doc=selectedPatientDoc
type=formType validation="browser" template="semanticUI"}}
<div class='two fields'>
{{> afQuickField name="firstName"}}
{{> afQuickField name="lastName"}}
</div>
<div class='two fields'>
{{> afQuickField name="phn.type"}}
{{> afQuickField name="phn.value" class="ramq"}}
</div>
<div class='two fields'>
{{> afQuickField name="birthDate"}}
{{> afQuickField name="gender"}}
</div>
<button class="ui submit button" type="submit">Save</button>
<div class="ui error message"></div>
{{/autoForm}}
</div>
</template>
I want to handle the text change event for input with name phn.value. Based on the text, I want to auto-populate two other fields: gender and date of birth. I am doing it by changing the template data directly as follows:
Template.patientForm.events({
'change .ramq': function changeRAMQ(event, templateInstance) {
const { patient } = templateInstance.data;
if (patient.phn.type === 'RAMQ') {
const ramq = event.target.value;
const yy = parseInt(ramq.substr(4, 2), 10);
let mm = parseInt(ramq.substr(6, 2), 10);
const dd = parseInt(ramq.substr(8, 2), 10);
patient.gender = mm < 13 ? 'Male' : 'Female';
if (mm > 50) {
mm -= 50;
}
patient.birthDate = moment(new Date(yy, mm, dd)).format('YYYY-MM-DD');
}
},
});
I am getting the template data and directly modifying the gender and birthdate when the phn.value changes. However, the modified gender and birthdate does not re-render in the autoform / blaze template. Any way by which I can force re-render of Blaze template or alternate ways to effect changes to other controls in Blaze template?

You can't modify the template data directly (you can, but that's not reactive and will be overwritten). Where are you getting the template data from? A collection? a reactive variable? If so, modify the data there -- Blaze will notice the change and re-render.
Supposedly something like this will work:
Patients.update(templateInstance.data._id, {$set: {
birthDate: ..,
gender: ..
}});

To enable reactivity and thus the re-rendering of the fields you should use a ReactiveVar (or ReactiveDict)
You can do this like this:
Template.patientForm.onCreated(function(){
const instance = this;
instance.birthDate = new ReactiveVar()
});
And in your helpers and events you can use instance.birthDate.set() / get()
Template.patientForm.helpers({
birthDate() {
return Template.instance().birthDate.get()
}
});
Template.patientForm.events({
'click something'(event, instance){
....
instance.birthDate.set(value);
....
}
});

Related

Reuse Meteor template as inclusion with different helpers

I'd like to re-use a Meteor template as an inclusion (i.e. using {{> }}) in two different contexts. I know I can pass in different data with the inclusion by using {{> templateName data1=foo data2=bar}}, but I'm struggling to figure out how I can provide different helpers based on the context. Here's the template in question:
<template name="choiceQuestion">
<div class="choice-grid" data-picks="{{numberOfPicks}}" data-toggle="buttons">
{{! Provide for the user to make multiple selections from the multiple choice list }}
{{#if hasMultiplePicks}}
{{#unless canPickAll}}<span class="help-block text-center">Pick up to {{numberOfPicks}}</span>{{/unless}}
{{#each choices}}
<label class="btn btn-default"><input type="checkbox" class="choice" name="{{this}}" autocomplete="off" value="{{this}}" checked="{{isChecked}}"> {{this}}</label>
{{/each}}
{{/if}}{{! hasMultiplePicks}}
{{#if hasSinglePick}}
{{#each choices}}
<label class="btn btn-default"><input type="radio" class="choice" name="{{this}}" id="{{this}}" autocomplete="off" value="{{this}}" checked="{{isChecked}}"> {{this}}</label>
{{/each}}
{{/if}}{{! hasSinglePick}}
</div>
</template>
and here's how I've reused it:
{{> choiceQuestion choices=allInterests picks=4}}
The key component of the template is a checkbox. In one context, it will never be checked. In another, it may be checked based on the contents of a field in the user document. I've added checked={{isChecked}} to the template. I've read this boolean attribute will be omitted if a falsey value is returned from the helper which should work well for my purposes.
The template's JS intentionally does not have an isChecked helper. I had hoped I could provide one on the parent where the template is included in the other context in order to conditionally check the box by returning true if the checked conditions are met, but the template doesn't acknowledge this helper.
Here's the template's JS:
Template.choiceQuestion.helpers({
hasSinglePick: function() {
return this.picks === 1;
},
hasMultiplePicks: function() {
return this.picks > 1 || !this.picks;
},
numberOfPicks: function() {
return this.picks || this.choices.length;
},
canPickAll: function() {
return !this.picks;
},
});
and the parent's JS:
Template.dashboard.helpers({
postsCount: function() {
var count = (Meteor.user().profile.posts||{}).length;
if (count > 0) {
return count;
} else {
return 0;
}
},
isChecked: function() {
return (((Meteor.user() || {}).profile || {}).contentWellTags || []).indexOf(this) > -1 ? 'checked' : null;
}
});
Template.dashboard.events({
'click .js-your-profile-tab': function(){
facebookUtils.getPagesAssumeLinked();
}
});
I've tried a few other approaches as well. I tried passing the helper to the template along with the other context (i.e. {{> templateName data1=foo data2=bar isChecked=isChecked}}. This kinda works, but it calls the helper immediately. This breaks these since I need to use a value from the context to determine what to return from my helper. Since this value doesn't exist when the function returns, the function always returns undefined.
If I return a function from this helper rather than the value and then pass the helper into the template inclusion along with the data context, I get better results. In fact, my console logs show the desired output, but I still don't end up with the checked box I expect.
Here's what that looks like. Returning a function:
isChecked: function() {
var self = this;
return function() {
return (((Meteor.user() || {}).profile || {}).contentWellTags || []).indexOf(this) > -1 ? 'checked' : null;
};
}
and passing that to the template:
{{> choiceQuestion choices=allInterests picks=4 isChecked=isChecked}}
Is there an established pattern for overriding template helpers from the parent or for including helpers on the parent that are missing from the child template? How can I achieve this?

UI updates with Meteor.js?

I'm having issues finding a way to update the UI AFTER adding to a collection. So in the example below after you click the button and add to the collection an additional input is added to the DOM. All good, but i'd like to find a way to target the new input element and preferably give it focus in addition to CSS. Unfortunately I can't find any info that helps solve this AFTER the DOM's been updated. Any ideas? Thanks
<body>
{{> myTemplate}}
</body>
<template name="myTemplate">
{{#each myCollection}}
<input type="text" value="{{name}}"><br>
{{/each}}
<br>
<button>Click</button><input type="text" value="test" name="testBox">
</template>
test = new Meteor.Collection("test");
if (Meteor.isClient) {
Template.myTemplate.rendered = function()
{
console.log("rendered");
this.$('input').focus()
}
Template.myTemplate.helpers({
'myCollection' : function(){
var testCollection = test.find({});
console.log("helpers");
return testCollection;
}
});
Template.myTemplate.events({
'click button': function(event){
event.preventDefault();
var val = $('[name="testBox"]').val();
console.log("events");
return test.insert({name: val});
}
});
}
Turn what you're adding into a template and call that template's rendered to set the needed css or do whatever transforms are needed.
HTML:
<body>
{{> myTemplate}}
</body>
<template name="item">
<input type="text" value="{{name}}"><br>
</template>
<template name="myTemplate">
{{#each myCollection}}
{{> item this}}
{{/each}}
<br>
<button>Click</button><input type="text" value="test" name="testBox">
</template>
JS:
test = new Meteor.Collection("test");
if (Meteor.isClient) {
Template.myTemplate.onRendered(function() {
console.log("rendered");
this.$('input').focus()
});
Template.myTemplate.helpers({
'myCollection' : function(){
var testCollection = test.find({});
console.log("helpers");
return testCollection;
}
});
Template.myTemplate.events({
'click button': function(event){
event.preventDefault();
var val = $('[name="testBox"]').val();
console.log("events");
test.insert({name: val});
}
});
Template.item.onRendered(function() {
this.$('input').focus();
}
}
On a side note, you should use onRendered instead of rendered as the latter has been deprecated for the former.
Do it inside of your myCollection helper function. Use jquery to target the last input in your template and focus it, add css. Meteor's template helpers are reactive computations based on the DOMs usage of their reactive variables, so it will run each time the DOM updates based on your collection.

Meteor Block Helper that acts like a template

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>

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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