I find in several backbone examples different ways to do the same thing
I'd just like to know if any of them is better, and in case they're exactly the same which is the more accepted style
$('#header').html(new HeaderView().render());
vs
new HeaderView({el:$('#header')).render();
and
this.$el.html( this.template() );
vs
$(this.el).html( this.template() );
and finnally
render: function() {
[...]
return this.el;
}
vs
render: function() {
[...]
return this;
}
Send, or not to send, el in the constructor
I think always that is possible is better to send el in the constructor, this way the JS logic will be more decoupled from the DOM structure and not any DOM element name is hard-coded into the JS code.
This is also better for testing proposes so you don't need to recreate the production DOM structure in your tests and you can create a dummy DOM structure and instantiate your Views making reference to any DOM element in your dummy DOM structure.
Also the View becomes more reusable.
Using this.$el
I think in a performance point of view is better to use:
this.$el
VS
$(this.el)
Due the first option is already precompiled. jQuery consume resources transforming a simple DOM element in a jQuery DOM element and if you use this.$el this is done only once.
What to return in render()
As #muistooshort has said, the standard is to return this. Normally when you call render() what you only need from outside is el so returning el has a lot of logic but people has agreed to returning this.
In some way it has its logic due this expression looks awkward:
$('#header').html(new HeaderView().render())
But this other looks very much intuitive and self explained:
$('#header').html(new HeaderView().render().el)
Related
I am using the following directive to create a ckEditor view. There are other lines to the directive to save the data but these are not included as saving always works for me.
app.directive('ckEditor', [function () {
return {
require: '?ngModel',
link: function ($scope, elm, attr, ngModel) {
var ck = ck = CKEDITOR.replace(elm[0]);
ngModel.$render = function (value) {
ck.setData(ngModel.$modelValue);
setTimeout(function () {
ck.setData(ngModel.$modelValue);
}, 1000);
}; }
};
}])
The window appears but almost always the first time around it is empty. Then after clicking the [SOURCE] button to show the source and clicking it again the window is populated with data.
I'm very sure that the ck.setData works as I tried a ck.getData and then logged the output to the console. However it seems like ck.setData does not make the data visible at the start.
Is there some way to force the view window contents to appear?
You can call render on the model at any time and it will simply do whatever you've told it to do. In your case, calling ngModel.$render() will grab the $modelValue and pass it to ck.setData(). Angular will automatically call $render whenever it needs to during its digest cycle (i.e. whenever it notices that the model has been updated). However, I have noticed that there are times when Angular doesn't update properly, especially in instances where the $modelValue is set prior to the directive being compiled.
So, you can simply call ngModel.$render() when your modal object is set. The only problem with that is you have to have access to the ngModel object to do that, which you don't have in your controller. My suggestion would be to do the following:
In your controller:
$scope.editRow = function (row, entityType) {
$scope.modal.data = row;
$scope.modal.visible = true;
...
...
// trigger event after $scope.modal is set
$scope.$emit('modalObjectSet', $scope.modal); //passing $scope.modal is optional
}
In your directive:
ngModel.$render = function (value) {
ck.setData(ngModel.$modelValue);
};
scope.$on('modalObjectSet', function(e, modalData){
// force a call to render
ngModel.$render();
});
Its not a particularly clean solution, but it should allow you to call $render whenever you need to. I hope that helps.
UPDATE: (after your update)
I wasn't aware that your controllers were nested. This can get really icky in Angular, but I'll try to provide a few possible solutions (given that I'm not able to see all your code and project layout). Scope events (as noted here) are specific to the nesting of the scope and only emit events to child scopes. Because of that, I would suggest trying one of the three following solutions (listed in order of my personal preference):
1) Reorganize your code to have a cleaner layout (less nesting of controllers) so that your scopes are direct decendants (rather than sibling controllers).
2) I'm going to assume that 1) wasn't possible. Next I would try to use the $scope.$broadcast() function. The specs for that are listed here as well. The difference between $emit and $broadcast is that $emit only sends event to child $scopes, while $broadcast will send events to both parent and child scopes.
3) Forget using $scope events in angular and just use generic javascript events (using a framework such as jQuery or even just roll your own as in the example here)
There's a fairly simple answer to the question. I checked the DOM and found out the data was getting loaded in fact all of the time. However it was not displaying in the Chrome browser. So the problem is more of a display issue with ckEditor. Strange solution seems to be to do a resize of the ckEditor window which then makes the text visible.
This is a strange issue with ckeditor when your ckeditor is hidden by default. Trying to show the editor has a 30% chance of the editor being uneditable and the editor data is cleared. If you are trying to hide/show your editor, use a css trick like position:absolute;left-9999px; to hide the editor and just return it back by css. This way, the ckeditor is not being removed in the DOM but is just positioned elsewhere.
Use this java script code that is very simple and effective.Note editor1 is my textarea id
<script>
$(function () {
CKEDITOR.timestamp= new Date();
CKEDITOR.replace('editor1');
});
</script>
Second way In controller ,when your query is fetch data from database then use th
is code after .success(function().
$http.get(url).success(function(){
CKEDITOR.replace('editor1');
});
I know, that this thread is dead for a year, but I got the same problem and I found another (still ugly) solution to this problem:
instance.setData(html, function(){
instance.setData(html);
});
I'm writing some simple jasmine tests and I'm getting an exception since the code I'm testing is looking for a form that doesn't exist because there's no DOM when testing a js file only: $("form")[0] in the tested js file leads to:
TypeError: $(...)[0] is undefined
I read a bit about jasmine-jquery and realized I can use some html fixture with an external html file. That flow seems quite messy, since all I need to do is only to add an empty valid form so that the test (which focusing on something else) will run, something like <form></form> appending would be enough I think.
At first I thought that sandbox() function will be the solution, but it seems that it creates only divs, and I need a form.
Any simple way to add some elements by using only code in jasmine spec file?
The simplest solution is to add the form to the DOM by yourself in the before block and then delete it in the after block:
describe(function(){
var form;
beforeEach(function(){
form = $('<form>');
$(document.body).append(form);
});
it('your test', function(){
})
afterEach(function(){
form.remove();
form = null;
});
});
Also writing your sandbox helper isn't that hard:
function sandbox(html){
var el;
beforeEach(function(){
el = $(html);
$(document.body).append(el);
});
afterEach(function(){
el.remove();
el = null;
});
Another approach is to use jasmine fixture
The concept
Here's one way to think about it:
In jQuery, you give $() a CSS selector and it finds elements on the
DOM.
In jasmine-fixture, you give affix() a CSS selector and it adds those
elements to the DOM.
This is very useful for tests, because it means that after setting up
the state of the DOM with affix, your subject code under test will
have the elements it needs to do its work.
Finally, jasmine-fixture will help you avoid test pollution by tidying
up and remove everything you affix to the DOM after each spec runs.
See also: SO: dom manipulation in Jasmine test
You should use sandbox() to create a div and create a form element and append to sandbox, this is the safer way to jasmine take control to this fixtures in the DOM.
So we all know in an ajax update events must be rebound to new dom elements. Yes delegate is an option, but delegate doesn't work for all scenarios. For instance delegate won't help for something that needs to be done simply on load rather than on a click event.
Rather than split my code into delegate handlers and handlers that need to be rebound on updates, I would rather define a single method with a context parameter that gets called every time the page changes like so:
function onPageUpdate(context) {
$('a', context).click(...); // event handlers
$('.chart', context).addClass(...); // load handlers
}
On dom ready this will be called with the context parameter null. On an ajax update the context will container the new dom elements. This way I'll never have to worry about delegating or ajax updates again.
I'm having trouble getting this to work however. Given the ajax callback:
function onSuccess(data) {
// data contains new dom elements like: <div><a>Click</a><span>chart<span></div>
// replace old elements with new ones
$('a').replaceWith('a', data);
$('span').replaceWith('span', data);
// call pageUpdate with the new context
onPageUpdate(data);
}
Is it possible to make this work like I expect? The replacing works fine, but onPageUpdate isn't binding anything to these new elements, I don't know if thats because the context is just a string object or what. Can anyone think of a way to make this work?
In my mind this is a better solution than delegate, because theres only one method for all handlers and only the elements that need a binding will own it.
From jQuery() - jQuery API
jQuery( selector [, context] )
selector A string containing a selector expression
context A DOM Element, Document, or jQuery to use as context
If the context isn't the correct type - such as passing a string - it's simply going to be ignored. Try wrapping your HTML string in a jQuery object, then use that as the context for your selectors, like so:
var $context = $(data);
$('a').replaceWith('a', $context);
$('span').replaceWith('span', $context);
// call pageUpdate with the new context
onPageUpdate($context);
I won't answer to your question, Anthony Grist's answer is quite right, but there are some things you said that I don't understand. Could you explain them to me ?
For instance delegate won't help for something that needs to be done simply on load rather than on a click event
Sorry but I don't get it, do you have an example ?
In my mind this is a better solution than delegate, because theres
only one method for all handlers and only the elements that need a
binding will own it.
I don't get it too:
only one method: which method are you talking about ?
only the elements ... will own it: it's also the case with delegate, and more, if you have let's say 10 anchor element, only ONE handler would be bound, instead of 10 in your solution
On your method onPageUpdate you're mixing two things: event handling ($("a").click(...)) and DOM modification ($(".char").addClass(...)). Maybe that's why you're confusing about delegate's ability to resolve your problem.
Firstly I am very new to all forms of javascript, particularly anything remotely AJAX. That said, over the course of the last day I have managed to code a script that dynamically refreshes a single div and replaces it with the contents of a div on another page.
The problem however is that several of my other scripts do not work in the ajax refreshed content. The most important of which being "colorbox".
I have spent several hours this evening researching this and am seeing lot's of stuff regarding .load, .live... updating the DOM on refresh etc...etc... But to be quite honest most of it is going over my head currently and I wouldn't know where to begin in terms of integrating it with the code I currently have.
My Ajax refresh code is as follows (My apologies if I haven't used best practice, it was my first attempt):-
$(function() {
$(".artist li.artist").removeClass("artist").addClass("current_page_item");
$("#rightcolumnwrapper").append("<img src='http://www.mywebsite.com/wp-content/images/ajax-loader.gif' id='ajax-loader' style='position:absolute;top:400px;left:190px;right:0px;margin-left:auto;margin-right:auto;width:100px;' />");
var $rightcolumn = $("#rightcolumn"),
siteURL = "http://" + top.location.host.toString(),
hash = window.location.hash,
$ajaxSpinner = $("#ajax-loader"),
$el, $allLinks = $("a");
$ajaxSpinner.hide();
$('a:urlInternal').live('click', function(e) {
$el = $(this);
if ((!$el.hasClass("comment-reply-link")) && ($el.attr("id") != 'cancel-comment-reply-link')) {
var path = $(this).attr('href').replace(siteURL, '');
$.address.value(path);
$(".current_page_item").removeClass("current_page_item");
$allLinks.removeClass("current_link");
$el.addClass("current_link").parent().addClass("current_page_item");
return false;
}
e.preventDefault();
});
$.address.change(function(event) {
$ajaxSpinner.fadeIn();
$rightcolumn.animate({ opacity: "0.1" })
.load(siteURL + event.value + ' #rightcolumn', function() {
$ajaxSpinner.fadeOut();
$rightcolumn.animate({ opacity: "1" });
});
});});
I was hoping someone might be kind enough to show me the sort of modifications I would need to make to the above code in order to have the colorbox load when the contents of #rightcolumn have been refreshed.
There is also a second part to this question. My links to the pictures themselves are now also being effected by the hashtag due to the above code which will in turn prevent the images themselves from loading correctly in the colorbox I should imagine. How can I prevent these images from being effected and just have them keep the standard URL. I only want the above code to effect my internal navigation links if at all possible.
Many thanks guys. I look forward to your replies.
That's a lot of code to review so I'll focus first on the conceptual side of things. Maybe that you will give you some clues...
It sounds like when you load content via Ajax the DOM is changed. No worries, that's kind of what we expect. However, scripts loaded before the Ajax calls may have difficulty if they are bound to elements that weren't there at page load time or are no longer there.
JQuery's live function is one solution to that. Instead of binding to a specific element (or collection of elements) at particular point in time, live lets you specify a binding to an element (or collection) of elements without regard to when they show up in the DOM (if ever).
ColorBox, however, in its default "vanilla" use abstracts that all away and, I believe, uses classic DOM binding - meaning the elements must be present at bind time. (Since you don't show your call to ColorBox I can't see how your using it.)
You may want to consider re-initalizing ColorBox after each content load by Ajax to be certain the binding happens the way you need it to.
Use $('selector').delegate() it watches the DOM of 'selector' and .live() is deprecated.
Use this to watch your elements AND fire the colorbox initilization. This way the colorbox is not dependent on the DOM element, but the other way around.
$("body").delegate("a[rel='lightbox']", "click", function (event) {
event.preventDefault();
$.colorbox({href: $(this).attr("href"),
transition: "fade",
innerHeight: '515px',
innerWidth: '579px',
overlayClose: true,
iframe: true,
opacity: 0.3});});
This should basically solve your problem and is cross browser tested.
The a[rel='lightbox'] in the delegate closure is the reference to what ever link you're clicking to fire the colorbox, whether it has been loaded with the initial DOM or with an AJAX request and has been added to the DOM in a live fashion. ie: any tag like this:
<a rel='lightbox' href="http://some.website.com">Launch Colorbox</a>
I'm in the process of converting my web app to a fully AJAX architecture.
I have my master page that is initially loaded and a div container that is loaded with dynamic content.
I created a few jQuery plugins that I apply to certain elements in order to extend their functionality. I'd normally call the functions as follows during each page load:
$(document).ready(function () {
// Enable fancy AJAX search
$(".entity-search-table").EntitySearch();
});
This would find the appropriate div(s) and call the plugin to enable the necessary functionality.
In an AJAX environment I can't just apply the plugin during the page load since elements will be added and removed dynamically.
I'd like to do something like this:
$(document).ready(function () {
// Enable fancy AJAX search
$(".entity-search-table").live("load", function () {
$(this).EntitySearch();
});
});
Question: Is there any way that I can trigger an event when a <div> or other element that matches a selector is added to the DOM?
It seems incredibly wasteful to activate the plug-in every time an AJAX request completes. The plug-in only needs to be applied to the element once when it is first added to the DOM.
Thanks for any help!
Yes - take a look at liveQuery. Example:
$('.entity-search-table').livequery(function(){
$(this).EntitySearch();
});
It seems incredibly wasteful to activate the plug-in every time an AJAX request completes. The plug-in only needs to be applied to the element once when it is first added to the DOM.
You can get the best of both worlds here, for example:
$("#something").load("url", function() {
$(".entity-search-table", this).EntitySearch();
});
This way it's only applying the plugin to the .entity-search-table elements you just loaded, since we specified a context to $(selector, context) to limit it.
The DOM 2 MutationEvent is what you really want, but unfortunately it isn't supported by IE. You'll need to either use live()/ delegate() binding in the plug-in, or (as I did when I had to work around this) use callbacks from your AJAX loaders indicating the scope of what has changed.
Use the live binding in your plugin code directly
jQuery.fn.EntitySearch = function() {
this.live(..., function(){ your plugin code });
return this;
}