I need to display a potential huge treeview in my webapplication. During testing I found out that using the standard template rendering method of angular with ngRepeat and ngInclude are not performing enough (it takes around 5 seconds to show the info). Removing binding (because there is no use for it) gave no results.
After some googling I found a module called scalyr https://github.com/scalyr/angular This should really optimize the performance of rendering.
My code:
<script type="text/ng-template" id="tree_item_renderer.html">
{{data.name}}
<ul>
<li sly-repeat="data in data.childNodes " ng-include="'tree_item_renderer.html'"></li>
</ul>
</script>
<ul>
<li sly-repeat="data in vm.rows" ng-include="'tree_item_renderer.html'"></li>
</ul>
When running this code I get an exception
Error: [$compile:multidir] Multiple directives [slyRepeat, ngInclude] asking for transclusion on: <li sly-repeat="data in data.childNodes " ng-include="'tree_item_renderer.html'">
Is this fixable? Or is it impossible to run scalyr with ng-Include.
There is a problem with multiple transclusions on the same element, but there's an easy solution:
<li sly-repeat="data in data.childNodes ">
<div ng-include="'tree_item_renderer.html'"></div>
</li>
There is a module that offer multiple transclusions, but I've never played with it, so I'm not sure that it works.
When you figure out your tree, tell me if the sly-repeat is worth it, as I've got a huge tree to build as well.
Related
I'm maintaining a legacy product, and found a quirk that I haven't seen before in AngularJS.
As demonstrated in this Plunker, the following HTML fails to render:
<p ng-repeat="item in items">
<div>{{item.type}}</div>
</p>
while this renders just fine:
<div ng-repeat="item in items">
<div>{{item.type}}</div>
</div>
Is there any explanation as to why this might be the case?
I was rather caught off-guard with this, as I don't recall seeing anything about this in the development resources.
It most likely is due to the fact that the HTML spec specifies that for a <p> immediately followed by a <div>, the close tag is optional.
I would assume this means that somehow the browser silently ignores the presence of any explicit source-specified </p> tag. I'd guess that when ng-repeat is parsing the source, it then cannot find the end of the repeated section, and therefore cannot render as expected.
I am trying to use ng-repeat to spit out part of a url (my.url) within ng-include. Unfortunately I cant seem to get it to work. It works when I dont place it within an ng-include, so I know that part isnt the issue. THe issue seems to be when I place {{my.url}} inside ng-repeat and attached to the first (static) part of the url.
What i am aiming for is the ng-include to use "filepath/filepath/mypage.html
my.url is the mypage.html bit.
Anybody able to advise?
<uib-tab ng-repeat="stuff in myList" heading="{{my.text}}" class="sg-tabbed-titles">
<div class="tab">
<ul class="tabbed-list">
<li class="tab-content">
<div ng-include="'\filepath/filepath/{{my.url}}\'"></div>
</li>
It should be
<div ng-include="'filepath/filepath/' + my.url"></div>
ngInclude takes expression. It means that you need to use normal string concatenation just like you would do in regular javascript code.
We are kicking a new project using angularJS :) and one of the requirements is a tree control.
The tree control should support "Lazy Loading", So we could add nodes to it dynamically as we get more data using AJAX.
I saw the 2 directives below, but I do not think "Lazy Loading" is supported
so before I start developing it myself I am asking you folks :)
The 2 nice tree directives I saw:
https://github.com/eu81273/angular.treeview/blob/master/angular.treeview.js
https://github.com/nickperkinslondon/angular-bootstrap-nav-tree
Thanks, Avi
Because AngularJS loads directives before any logic, you cannot use them very well for recursive operations, else you probably wouldn't need a directive for one in the first place.
However, one very pleasant workaround is using ng-include, as this doesn't have the above limitation. And then making a tree is extremely simple.
Where you want to tree, you have something like
<ul class="tree-container">
<li style="margin: 5px; list-style: none;" ng-repeat="d in vm.features" ng-include="'tree_item_renderer.html'"></li>
</ul>
then the include looks something like this
<script type="text/ng-template" id="tree_item_renderer.html">
<span ng-click="d.expand = !d.expand;vm.getChildNodes(d)" ng-show="!d.expand && d.hasChildren"><i class="fa fa-fw fa-plus-circle"></i></span>
<span ng-show="d.expand && d.hasChildren" ng-click="d.expand = !d.expand;d.children=null" ><i class="fa fa-fw fa-minus-circle"></i></span>
<span ng-show="!d.hasChildren" style="margin-left:28px"></span>
<ul>
<li style="list-style:none;" ng-repeat="d in d.children" ng-model="d" ng-include="'tree_item_renderer.html'"></li>
</ul>
</script>
In the controller vm.getChildNodes(d) call you can get the children for the currently expanded node. I expand the nodes and then actually asynchronously do a count for each node over odata to determine if the node has children, so I can show if one of the children has children of its own, but of course you could more efficiently track that in the database if you have control over that (I think I will update my model for this myself).
Note that I've implemented it so that if you open and close and then open, it actually reloads the nodes. You don't have to do that of course, but it saves me from having to implement a reload/refresh button otherwise and it's not like users are going to open/close trees over and over because they have nothing better to do. ;)
The added advantage I have is that I implement user input for some (most) of the nodes, e.g. select them, enter a value for them. I've noticed it is more efficient if these only exist 'on demand' in angular.
I have a HTML file it iterates over a list of objects as shown and every object has a template( stored in the db) that it uses I get "List" from a web service :-
<ul>
<li ng-repeat="object in List" ng-include="object.TemplateName" > </li>
</ul>
Let object.TemplateName be "template1"
A sample template would have a specific directive with the attributes needed and few html tags as shown "template1":-
template1:-
<directive1 s-web-service-path="object.WebServicePath" >
<h1>any html content</h1>
</directive1>
my directive calls a web service to get the content to be displayed and has its own template... instead of putting directives in a template and including them cant I directly call my directive depending upon the different types of objects that i obtain in List
something like
for Object.Type="1" i call directive1 instead of template1
for Object.Type="2" i call directive2 instead of template2
ngIf or ngSwitch might be helpful here, with a few extra wrapping elements within the ngRepeat, in order to dynamically choose what to include based on Object.Type. Using ngSwitch:
<ul>
<li ng-repeat="object in List">
<div ng-switch="object.Type">
<div ng-switch-when="'1'">
<div ng-include="object.TemplateName"></div>
</div>
<div ng-switch-when="'2'">
<directive1 s-web-service-path="object.WebServicePath" >
<h1>any html content</h1>
</directive1>
</div>
</div>
</li>
</ul>
The above is not tested, so there could potentially be an error. You might also be able to cut down on some of DOM nesting level by including the ng-switch-when attributes on the directive1 / ng-include divs, but the way above makes the behaviour clear, and avoids any unexpected issues that might arise from having multiple directives work on the same element.
I have a huge JSON object tree with two levels. First level has around 500 elements, and each element contains an average of 100 child elements.
I want to display the first level of the tree and I am doing it with a simple ng-repeat. When the user clicks on the element I want to display the child elements of that element. If I use a span ng-switch or a ng-show to show/hide child elements when the page first renders it freezes for around 10 seconds while generating all the HTML.
It doesn't sound like the right solution. There must be a different way of doing it, but I can't figure out. Anyone knows?
I have explained most in my comment, and here is a working plunker:
http://plunker.co/edit/RSZwfLlsCJ68MUkACbdp?p=preview
the new ng-if directive will do what you want
<h1>ng-if</h1> <h5>Click on the level to expand</h5>
<div class="well">
<ul class="nav nav-list" ng-repeat="(attr,element) in tree">
<li ng-click="expand=!expand" ng-class="{'active':expand}"><a>{{element.name}}</a></li>
<ul ng-if="expand" class="nav nav-list">
<li ng-repeat="item in element.items">{{item.name}}</li>
</ul>
</ul>
</div>
you can also do this in the "old-way" with ng-show using new ternary operator or its alternative expr && if_true || if_false
<h1>old-way</h1> <h5>Click on the level to expand</h5>
<small>use ternary operator or <pre>expand && element.items || []</pre></small>
<div class="well">
<ul class="nav nav-list" ng-repeat="(attr,element) in tree">
<li ng-click="expand=!expand" ng-class="{'active':expand}"><a>{{element.name}}</a></li>
<ul ng-show="expand" class="nav nav-list">
<li ng-repeat="item in (expand ? element.items : [])">{{item.name}}</li>
<!--<li ng-repeat="item in (expand && element.items || [])">{{item.name}}</li>-->
</ul>
</ul>
</div>
See this answer on ng-repeat performance. Essentially, it just takes a long time since Angular's ng-repeat, and basically all other directives, are set up to always look for updates in the whole JSON structure. So if you have lots of data and don't need live updates in the HTML view when changing the JSON, I wouldn't recommend using AngularJS. Generally, AngularJS performance also depends a lot on the browser and its JavaScript engine.
Alternatively, you could divide your JSON into subparts and then use pagination to display it.
I would recommend to fetch the data gradually from the server. Use server-side pagination and retrieve only the fields that you are going to display. Then, when a user clicks on one of the first level items, you can do another XHR to the server with the new data. I had similar requirements for a project and that solved the latency issue.
Regards,
Agustin.