I have a Meteor template that includes the following:
{{#with selected_recipe}}
{{>recipe}}
{{/with}}
In my code (Coffeescript), I want to call a function by name from my event map (Backbone-style):
Template.recipe.events = {
'click #btn-edit-recipe': 'editRecipe'
}
editRecipe = (event) ->
console.log # #should log the selected_recipe object
#edit recipe
However, this fails. When I click on my button in the recipe template, I get Uncaught TypeError: Object editRecipe has no method 'call' (liveui.js:651) I learned event maps from Backbone, and maybe Meteor is different. I can get it to work with:
Template.recipe.events = {
'click #btn-edit-recipe': -> editRecipe.call(#, event)
}
Is this the right way to do this? Or am I making some simple error? I've always liked using event maps this way because it summarizes the behaviors of the rendered template in just a few lines. Anonymous functions can spread the list out, making it harder to read, and of course they are not reusable.
What you are doing (later one, where event definition points to a function) is right.
Event map with value as function name (string) is pattern specific to backbone. Meteor doesn't support it.
I've always liked using event maps this way because it summarizes the
behaviors of the rendered template in just a few lines.
But you can acheive similar functionality by doing something like this:
Template.recipe.doLogin = function(){};
Template.recipe.requestData = function(){};
// OR Another way
_.extend(Template.recipe, {
"openFile":function(){},
"editRecipe":function(){}
});
// now Events
Template.recipe.events {
'click #btn-edit-recipe': Template.recipe['editRecipe'],
'click #btn-create-recipe': Template.recipe['createRecipe']
}
Personally, I don't like event-maps. cause its a mapping, which developer has to maintain manually.
Edit: Working code # https://gist.github.com/3010818
Related
Is there any way to extract the entity's information(id, class, etc) that is intersected with a raycaster?
I tried to find the information from evt.detail.el but no success.
AFRAME.registerComponent('collider-check', {
init: function () {
this.el.addEventListener('raycaster-intersected', function (evt) {
console.log(evt.detail.el);
});
}
});
The issue is that the code above logs the raycasting entity, rather than the raycasted entity, so it is logging the cursor.
Using the code above, you can access the data you need by logging evt.detail.intersection.object.el. So you could do something like the following to access id and class, respectively:
console.log(evt.detail.intersection.object.el.id);
console.log(evt.detail.intersection.object.el.className);
Here is a demo of the code in action: https://codepen.io/dansinni/pen/bjjbWv
If you haven't bound this to the handler, and only need basic attribute data, you should also be able to do the following, but YMMV:
console.log(this.id);
console.log(this.className);
You should also be able to use a component with the cursor instead, and rely on the raycaster-intersection event. Note the difference in the docs: https://aframe.io/docs/master/components/raycaster.html#events
I'm looking through the Meteor simple tutorial and the way that 'this' binding in the different Template objects works seems inconsistent to me in my unknowledgeable state.
Template.body.events({
"submit .new-task": function(event) {
console.log(this); // Logs an empty object
}
})
Template.task.events({
"click .toggle-checked": function() {
console.log(this); // logs a task
}
});
I can see that task is an xml template defined in the view, which is a visual representation of the items returned by a function in the Template.body.helpers object.
I guess that the task objects are bound the html representation of each object (though I can't see how as there doesn't seem to be any identifying property within the li elements??)
Anyhow. When I click the task, this is the task. But when I submit the form, I was expecting this to be the body. Why is it not?
I was expecting Meteor to handle Template.body and Template.task in a similar way
In Meteor this referes to the data context. You define it with helpers or with the route controller ( IronRouter or FlowRouter)
Example:
{{#with myData}}
<h1>{{title}}</h1>
{{/with}}
js
Template.yourTemplate.helpers({
myData : function(){
return {
title : "My title"
}
}
})
You need to use the "event" argument
Template.task.events({
"click .toggle-checked": function( event , instance ) {
console.log( event );
}
});
The instance argument is also very useful. You have access to a jQuery selector like: instance.$() and it will only search for elements on your template and also child templates.
Personally I use the instance a lot. My Favorite pattern is:
Template.task.onCreated(function(){
this.vars = new ReactiveDict();
this.data = "some data";
});
Later if you want to access vars or data:
Events - You get this on the arguments
Helpers - var instance = Template.instance();
With instance you avoid storing states in the global namespace, like Session, and your code is a lot easier to maintain and understand. I hope this helps you to understand how template works in Blaze.
I've come across this situation several times now and I realise I'm not really confident about the 'meteor/right' way to handle it.
Suppose I have a form with several parts - each represented by a template - and within each part there are more templates representing eg. datepickers etc.
<template name='myForm'>
{{>partOne}}
{{>partTwo}}
<button class='submit'>Submit</button>
</template>
<template name='partOne'>
{{>widget}}
{{>widget}}
</template>
<template name='widget'>
<input class='datepicker' />
</template>
I want to keep track of my form as the user fills it out - on the level of the 'myForm' template - but all the events are happening at the level of 'widget'.
One solution I keep seeing (e.g. in this SO answer) is to just put everything in the global Session variable. Like so
Template.widget.events({
'click .select' : function(event, template){
var name = template.data.name;
Session.set(name, $(event.currentTarget).val());
}
});
And then in myForm I should do something like this
Template.myForm.rendered = function(){
Tracker.autorun(function(){
var name = Session.get('name');
// do something
});
}
But as my forms are getting more complicated, I find this is really turning into a mess on the myForm template level, all while filling up my Session variable with data that isn't really application-global.
I'd be really grateful for any ideas on how others deal with this ! Keeping templates and widgets modular while still being able to follow and react to their triggered events from parent templates...
You're not alone in feeling like something just isn't right. This is one of the reasons there's a lot of talk about a Blaze 2. Here's what I do:
Create an app global namespace (e.g. G = {}). I usually use the first letter of the app name & do this in lib/config/_namespace.js
Put your collections in G.Collections or G.C,
Put your shared functions in G.Fx, etc...
Put your template vars in G.T.
Then, save that variable to G.T.varName. In doing so, you can use it in rendered as well as events and helpers. As a perk, it's super easy to find all your "globals" because they're all in the G object. Additionally, you can now 'use strict' again.
Then, to keep it clean:
Template.parentTemplate.destroyed = function() {
G.T = {};
};
So if you need reactivity, just make a ReactiveDict:
Template.parentTemplate.created = function() {
G.T.RD = new ReactiveDict();
};
You can use a file-level ReactiveVar or ReactiveDict, instead of the Session object.
I have a template named profile which contains three other templates. One of these templates is {{> postlist}}
and the helper function for this template is
Template.postlist.helpers({
posts: function() {
return Posts.find({rph: {$in : postsArr}});
}
});
The problem is on going to the route, postlist template is empty, since postsArr is calculated later after the dom has loaded on the basis of other two templates. But, if I click on other route and come back to this route, the template renders properly.
What should I do that template renders properly initially itself?
The easiest way would be to us Session, though it's probably the worst option:
Template.postlist.helpers({
posts: function() {
return Posts.find({rph: {$in : Session.get('postsArr') }});
}
});
If you now call Session.set('postArr', ...) anywhere in your code the posts helper will update automatically. The second option is to use a shared reactive variable:
var postsArr = new ReactiveVar();
and then inside your helper:
return Posts.find({rph: {$in : posts.Arr.get() }});
Now you can do postsArr.set(...) and everything should work fine. Just remember to meteor add reactive-var do your project.
One last doubt is: where to put that reactive variable declaration? In most cases you can do away with putting in a single "controller" file. It will work as long as:
- you only have one instance of your template a time
- the code which sets ad gets the value of you reactive variable may be put in the same file
If one of the above conditions does not hold, then the only option to go, which is BTW the best possible, is to put your state variable in your template's scope. This is how you do it:
Template.postsList.created = function () {
this.postsArr = new ReactiveVar();
};
Template.postlist.helpers({
posts: function() {
return Posts.find({rph: {$in : Template.instance().postsArr.get() }});
}
});
From helpers you can always access postsArr using the Template.instance() routine which always return the current template instance, for which the helper was called. From event handlers, note that the second argument of your handler is always the template instance, which you're interested in.
If you need to access it from another templates, then you should probably put your state variable on the corresponding route controller. Assuming you're using iron-router, that would be:
Iron.controller().state.get('postsArr');
The Iron.controller routine grants you access to the current route controller. Read this for more details.
In my meteor app I need to load an array of items corresponding to the item clicked.As I'm new to meteor, I'm held up here.Here is my code.
Template.templatename.events({
'click .showdiv' : function()
{
Template.templatename.vname = function () {
return Db.find();
}
}
Can I set the variable vname dynamically by this code ? This is not working for me.
I think you're misunderstanding the notion of reactivity. A reactive data source will cause any functions which depend on it (including helpers) to rerun when its value is changed, which seems to be the behavior you're looking for here. Instead, you're rewriting the helper function itself every time an item is clicked, which kind of defeats the object of Meteor's reactive data model. Session variables could help:
Template.templatename.events({
'click .showdiv' : function() {
Session.set('vname', Db.find());
}
});
Template.templatename.vname = function () {
return Session.get('vname');
}
If you use an {{#each vname}} block in the templatename template, it will automatically update with the results of the Db.find() query when a .showdiv is clicked. If all you want to do is show the result of that query regardless of whether a click has been registered it would be as simple as:
Template.templatename.vname = function () {
return Db.find();
}
Note that it's still not clear exactly what data you're trying to populate here since the query will return a cursor (which is fine, but you need to loop through it using {{#each ...}} - use findOne if you only want one item), and its contents aren't going to depend on anything intrinsic to the click event (like which .showdiv you clicked). In the former example it will however fail to show anything until the first click (after which you would have to reset with Session.set('vname', null) to stop it showing anything again).