I am working on Test cases for Marionette's View. By using events attribute, I have written a callback function on click of an HTML element. The functionality is working but I am struggling in writing test cases. I am not able to cover that click event using Jasmine test cases.
I have used the Marionette Region to render the view.
I have tried using spies but those are not working.
Please find code below for more details:
var TestView = Backbone.Marionette.CompositeView.extend({
tagName: 'div',
className: 'test-menu',
childView: testMenuView,
childViewOptions: function() {
return {
'componentId': this.cid
};
},
template: _.template(testTemplate),
initialize: function(options) {
this.collection = this.options.testData;
},
onShow: function(collectionView) {
collectionView.$el.show();
},
attachHtml: function(collectionView,itemView) {
collectionView.$("#testMenu").append(itemView.el);
},
events: {
'click #testBtn': function (event) {
alert('testBtn Clicked');
}
}
});
I like to use JQuery where I can when I write tests due to it being less verbose, and for most events triggering the handlers with JQuery will also work fine.
Given that you've got everything else set up for running a Jasmine suite I'd do
it('reacts to click events on its button', function() {
var view = new TestView();
view.render();
view.$('#testBtn').click(); // or view.$('#testBtn').trigger('click')
//(verify that the view did what was expected)
});
If testing the alert is the actual problem then use a spy for that, e.g. spyOn(window, 'alert') and expect(window.alert).ToHaveBeenCalledWith('testBtn Clicked')
JQuery won't always be able to trigger event handlers that are bound with addEventListener. Click is not one of those events, but there are situations where I have to trigger events using for examples
var event = document.createEvent('Event');
event.initEvent('keydown');
event.keyCode = 40;
event.altKey = true;
view.el.querySelector('input').dispatchEvent(event);
But most of the time just using JQuery's .trigger or corresponding shortcut-function directly on the element you want is fine.
Related
I've been trying to debug my Backbone multi-page app for most of the day now to get rid of 'zombies', but unfortunately to no avail. Before today, I didn't even realize I have a zombie problem. What am I doing wrong?
This is my RegionManager:
var regionManager = (function() {
var currView = null;
var rm = {};
var closeView = function(view) {
if (view && view.close) {
view.close();
}
};
var openView = function(view) {
view.render();
if (view.onShow) {
view.onShow();
}
};
rm.show = function(view) {
closeView(currView);
currView = view;
openView(currView);
};
return rm;
})();
This is my View cleaning up function:
Backbone.View.prototype.close = function() {
if (this.onClose) {
this.onClose();
}
if (this.views) {
_.invoke(this.views, 'close');
}
// Unbind any view's events.
this.off();
// Unbind any model and collection events that the view is bound to.
if (this.model) {
this.model.off(null, null, this);
}
if (this.collection) {
this.collection.off(null, null, this);
}
// Clean up the HTML.
this.$el.empty();
};
I tried appending the View els directly to the body and using this.remove(); in the View clean-up function (instead of using a common el: $('#content') to which I am appending elements, then cleaning up by this.$el.empty()), but that didn't work either.
It might have something to do with my "global Events":
Backbone.Events.on('letterMouseDown', this.letterMouseDown, this);
But I take care of them with the onClose function:
onClose: function() {
Backbone.Events.off('letterMouseDown');
}
One problem I see is that your close function never removes the event delegator from the view's el. A view's events are handled by using the delegator form of jQuery's on to attach a single event handler to the view's el. Your close does:
this.$el.empty();
but that only removes the content and any event handlers attached to that content, it does nothing at all to the handlers attached directly to this.el. Consider this minimal example:
var V = Backbone.View.extend({
events: {
'click': 'clicked'
},
clicked: function() {
console.log('still here');
}
});
var v = new V({ el: '#el' });
v.close();
After that, clicking on #el will throw a 'still here' in the console even though you think that the view has been fully cleaned up. Demo: http://jsfiddle.net/ambiguous/aqdq7pwm/
Adding an undelegateEvents call to your close should take care of this problem.
General advice:
Don't use the old-school on and off functions for events, use listenTo and stopListening instead. listenTo keeps track of the events on the listener so it is easier to remove them all later.
Simplify your close to just this:
Backbone.View.prototype.close = function() {
if(this.onClose)
this.onClose();
if(this.views)
_.invoke(this.views, 'close');
this.remove();
};
Don't bind views to existing els. Let the view create (and own) its own el and let the caller place that el into a container with the usual:
var v = new View();
container.append(v.render().el);
pattern. If you must attach to an existing el then the view should override remove with a slightly modified version of the standard implementation:
remove: function() {
this.$el.empty(); // Instead of removing the element.
this.undelegateEvents(); // Manually detach the event delegator.
this.stopListening();
return this;
}
I'm pretty sure I found the root for my problem.
mu is too short was right, with the close() method I wasn't removing the events bound directly to my el (which I tried to do by this.off() - this.$el.off()/this.undelegateEvents() is the correct way). But for me, it only fixed the problem that events got called multiple times unnecessarily.
The reason I was plagued by 'zombie views' or unintended behavior was that I wasn't freeing up the memory in the View..
this.remove() only gets rid of the el and it's elements/events, but not the View's internal variables. To elaborate - in my View I have an array declared like so this.array: [] and I didn't have it freed in the onClose function.
All I had to do was empty it in the onClose function or initially declare the array as this.array: null so on recurrent View renderings it would at least free the previous array (it still should be freed on the onClose method though, because the array/object is still going to sit in the memory until browsing away from the page).
It was excruciating to debug, because it's a crossword game (at least my code is hard to read there) and sometimes the words didn't match up, but I didn't know where the problem was coming from.
Lessons learned.
Originally I wrote standard functions triggered by an on input event handler that I placed in the HTML. However, it was recommended to me to rather 'listen' for events using jQuery (to make for more readable code).
Question:
What is the difference in terms of processing between the two? (as in how is the code of each style interacting with the DOM).
Originally I had something like this:
HTML:
<input type='range' oninput='doStuff()'../>
JS:
function doStuff() {
//Things happen
}
Below is the refactored code:
var makeMusic = {
var1: val,
var2: val,
var3: val,
init: function() {
makeMusic.watchExperience();
},
watchExperience: function() {
$(document).on('input change', '#input_experience', function() {
//do stuff
}
},
anotherFunction: function() {
},
etc
}
var otherScript = {
init: function() {
},
etc
}
var Main = {
run: function() {
makeMusic.init();
otherScript.init();
}
}
$(document).ready(Main.run);
I think you are talking about custom event dispatchers and redirecting it to a standard event
Based on your example the orginal event given by the browser DOM which is onchange if you want to do a proxy for it then you definitely catch that event and trigger your oninput
Refer https://developer.mozilla.org/en-US/docs/Web/Guide/Events/Creating_and_triggering_events
You can capture all the events at document level or a wilcard ***** selector level and re-trigger oninput with a custom code
if you use JQuery it will also help
The difference is: you can handle the native hardware events in a more sophisticated manner. This allows you create your own framework which give more proper event names.
I want to validate a users input by keydown. For this I require a keydown event.
Unfortunatly I only have found custom model events:
initalize: function(){
this.model = new ModelClass();
this.model.bind("keydown", this.validate, this);
}
That approach surely is fine for model events but I don't believe this is the right way for view, ui-related stuff...
To give you a better explication, this is how I would like to use my event:
var SomeView;
SomeView = Backbone.View.extend({
events: {
"keydown input#some-field": "validate" // custom event
, "change input#some-field": "doSomethingElse" // predefined backbone event
},
validate: function(attr){
// validation
}
});
So what is the approach to create custom Backbone Events which are callable in the View?
what is the approach to create custom Backbone Events which are callable in the View?
I feel as if your problem is not a problem，because backbone.view default has been to support the events.
you can write code like what you want to:
//This is the right thing to do
SomeView = Backbone.View.extend({
events: {
"keydown input#some-field": "validate" // custom event
, "change input#some-field": "doSomethingElse" // predefined backbone event
},
validate: function(attr){
// validation
}
});
Reference here：
http://backbonejs.org/docs/todos.html#section-22
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
EDIT :
you can see here:
http://backbonejs.org/docs/backbone.html#section-156
The most critical sentence is：
this.$el.delegate(selector, eventName, method);
because backbone's events is jquery's delegate(http://api.jquery.com/delegate/),so jQuery's delegate to support the event, backbone are available.
I'm not sure I'm understanding what the problem is. Your second example is definitely how I would and have gone about setting up event handlers in Backbone Views. Backbone's validate method only exists in the model and is called automatically before the models set and save are called. It is left undefined as default. If you are validating in the view though your way should work. But i believe event handling functions are only passed the event. so it should probably be
validate: function (event) {
// do Something here
}
also you should keep in mind that backbone event delegation takes place in the el. so you will need to either set it manually or render into it in order for event delegation to to work
I have the following view, where I'm trying to bind the click event to a delete button, but it doesn't seem to be triggering anything. Not getting any errors in console, it just doesn't seem to be binding the "click" event.
The span.delete element is deeply nested within a bunch of other elements, not sure if that matters, I've tried it as a direct child element as well, but still no go.
var ListRow = Backbone.View.extend(
{
events:
{
'click span.delete': 'remove'
},
initialize: function()
{
_.bindAll(this, 'render', 'unrender', 'remove');
this.model.bind('remove', this.unrender);
},
render: function()
{
this.el = _.template($('#tpl-sTableList_' + key + 'Row').html());
return this;
},
unrender: function()
{
$(this.el).fadeOut();
},
remove: function()
{
this.model.destroy();
}
});
There is no default remove event on a model, there is only a remove event coming from the collection, so if you want to remove a view when the model gets removed from the collection, it's probably better to put a
this.collection.bind('remove', this.onRemove, this);
in your ListView (as I assume you're using a ListView and a ListItemView based on your example) and then your onRemove method passes the model as an argument so you can find the view that's associated with it.
Found the problem, it was because I was only setting the el object, but not rendering it, so instead of:
this.el =
should be
$(this.el).html();
Otherwise all works as expected.
I have two views, for simplicity sake a parent/child. The child is using trigger to throw an event. I am not seeing it in the handler of the parent. Is the below valid?
var parent = Backbone.View.extend({
events: { "childevent": "run" },
run: function(e) {
console.log(e);
},
render: function() { /* render the child here */ }
});
var child = Backbone.View.extend({
someAction: function() { this.trigger('childevent'); }
});
Figured it out! $(this.el).trigger('childevent'); works.
Shouldn't it be events: { "childevent": "run" } instead? There is no way to access the actual anonymous function in this place in the code.
Backbone store a jQuery reference to the view's node in this.$el property so you can spare some performance using it rather than re-compute the reference by $(this.el).
// use "this.$el.trigger()" to refer to jQuery's object
this.$el.trigger('childevent');
Obviously late, but for anyone else who comes across this:
the events property on a view is for auto-binding Html DOM events from components within the views el or $el elements, and the syntax involves both a UI event and a selector as the key in pair:
events: { "click #someButton", "clickHandler" }
To listen to events from other Models or Views, you use this.listenTo( target, ..... )