Im trying to optimice the page loading speed when rendering tables with many rows(columns min. 25x).
I am not experienced debugging/improving performance on angular apps so quite lost on what could be involved in this lack of speed.
Here is Chrome timeline report for 5 row query:
Here is Chrome timeline report for 100 row query:
The XHR load(api/list/json/Chemical...) increases in time as more rows are rendered on the table.
The server response with the data is returned fast(not the bottle neck):
Here is the template for the table:
<tbody ng-if="compressed">
<tr ng-if="dbos && (rows.length == 0)">
<td class="tableColumnsDocs"><div class="tableButtons"> </div></td>
<td class="tableColumnsDocs"><div>No results</div></td>
<td class="tableColumnsDocs" ng-repeat="attobj in columns track by $index" ng-if="$index > 0">
<p> </p>
</td>
</tr>
<tr class="tableRowsDocs" ng-repeat="dbo in rows track by $index">
<td class="tableColumnsDocs"><div ng-include="'link_as_eye_template'"></div></td>
<td class="tableColumnsDocs" ng-repeat="attobj in columns track by $index">
<div ng-init="values = dbo.get4(attobj.key); key = attobj.key; template = attobj.template || getAttributeTemplate(dbo.clazz + attobj.key);">
<div class="content" ng-include="template"></div>
<div class="contentFiller" ng-include="template"></div>
</div>
</td>
</tr>
</tbody>
And here templates the table will call:
<script type="text/ng-template" id="plain_values_template">
<p ng-repeat="v in values track by $index">{{ v }}</p>
</script>
<script type="text/ng-template" id="links_as_dns_template">
<div ng-repeat="dbo in values track by $index" ng-include="'link_as_dn_template'"></div>
</script>
<script type="text/ng-template" id="json_doc_template">
<textarea class="form-control" rows="{{values.length + 2}}" ng-trim="false" ng-readonly="true">{{ values | json }}</textarea>
</script>
<script type="text/ng-template" id="link_as_dn_template">
<p>{{ dbo.displayName() }}</p>
Relevant controller part:
$scope.getAttributeTemplate = function(str) {
//console.log("getAttributeTemplate"); console.log(str);
if ($templateCache.get(str + ".template")) {
return str + ".template";
}
var a = str.split(/(>|<)/);
//console.log(a);
if ((a.length - 1) % 4 == 0) {
return "links_as_dns_template";
}
var clsname = a[a.length - 3];
if (clsname == "*") {
return "plain_values_template";
}
var attname = a[a.length - 1];
var cls = datamodel.classes[clsname];
var att = cls.attribute[attname];
if (!att) {
return "plain_values_template";
}
if (att.type == "ref") {
return "links_as_dns_template";
}
return "plain_values_template";
};
I am new to angular and performance opt. so any tips on how to improove or bad practice highlight will be very helpful!
Long tables are angular's biggest evil, because of the hell-as-slow base directives such as ng-repeat
Some easy and obvious stuffs :
I see a lot of bindings in the row/cell templates without one-time binding (::). I dont think your row data is mutating. switching to one-time bindings will reduce the watchers count -> perf.
Some harder stuff :
Quick answer :
dont let angular handle the performance bottleneck
Long answer :
ng-repeat is supposed to compile it's transcluded content once. But using ng-include is killing this effet, causing every row to call compile on their ng-included contents. The key for good performance in big table is to be able to generates (yea, manually, which $compile, $interpolate and stuff) a unique compiled row linking function, with less as possible angular directives - ideally only one-time expression bindings, and to handle row addiction/removal manually (no ng-repeat, you own directive, your own logic)
You should AT LEAST find a way to avoid the second nested ng-repeat on' ng-repeat="attobj in columns track by $index"'. This is a dual repeated on each row, killing compilation &linking (rendering perf) and watcher count (lifecycle perf)
EDIT : as asked, a "naive" example of what can be done to handle the table rendering as manually (and fast) as possible. Note that the example does not handle generating the table header, but it's usually not the hardest thing.
function myCustomRowCompiler(columns) {
var getCellTemplate = function(attribute) {
// this is tricky as i dont know what your "getAttributeTemplate" method does, but it should be able to return
// the cell template AS HTML -> you maybe would need to load them before, as getting them from your server is async.
// but for example, the naive example to display given attribute would be
return $('<span>').text("{{::model."+ attribute +"}}"); // this is NOT interpolated yet
};
var myRowTemplate = $('<tr class="tableRowsDocs">');
// we construct, column per column, the cells of the template row
_.each(columns, function(colAttribute, cellIdx) {
var cell = $("<td>");
cell.html(getCellTemplate());
cell.appendTo(myRowTemplate);
})
return $compile(myRowTemplate); // this returns the linking function
}
and the naive usage :
function renderTableRows(dbos, columns) {
var $scope; // this would be the scope of your TABLE directive
var tableElement = $el; // this would be your table CONTENT
var rowLinker = myCustomRowCompiler(columns); // note : in real life, you would compile this ONCE, but every time you add rows.
for(var i=0; i<dbos; i++) {
var rowScope = $scope.$new(); // creating a scope for each row
rowScope.model = dbos[0]; // injecting the data model to the row scope
rowLinker(rowScope, function(rowClone) { // note : you HAVE to use the linking function second parameter, else it will not clone the element and always use the template
rowClone.appendTo(tableElement);
});
}
};
This is the approach i've been using to my own projects's table framework (well, more advanced, but this is really the global idea), allowing to use angular power to render the cell content ( 'getCellTemplate' implementation can return html with directive, which will be compiled), using filter even including directives in the cell, but keeping the table rendering logic to myself, to avoid useless ng-repeat watch, and minimizing the compilation overheat to it's minimum.
Related
Description
I'm using AngularJS
I have a table that I want to show it as "Data Table" using DataTable jQuery plugin (http://datatables.net/docs/DataTables/1.9.4/DataTable.html).
The logic
Create table table markup.
Add ng-repeat using $scope.entities on the row .
Run the plugin on the table.
The problem
In the first time that I run it, everything is OK.
The problem start when I need to change the $scope.entities (For example: user select another list)
In the snippets below I was created simpler scenario but the logic is same.
Steps
Run the snippet (probably done automatic).
Click on destroy button. It will destroy the plugin and return the table to original html.
Click on Add row. It should add row to the table The problem is that all the rows were deleted instead of adding the row.
Note
I saw some angular directives who integrating with the plugin (datatable). I can't using it. I need to understand why the view nodes are deleting.
angular.module('myApp', []).
controller('ctrl', function($scope, $timeout) {
$scope.test = 'test';
$scope.generateData = function() {
var temp = [];
for (var i = 0; i < 5; i++) {
temp.push({
d1: Math.floor(Math.random() * 10),
d2: Math.floor(Math.random() * 10),
d3: Math.floor(Math.random() * 10)
});
}
$scope.entities = temp;
$timeout(function(){
$scope.dt();
});
};
$scope.dt = function(){
$timeout(function() {
if (!$scope.dataTable) {
$scope.dataTable = $('table').dataTable();
}
});
}
$scope.destroy = function(){
if ($scope.dataTable) {
$scope.dataTable.fnDestroy();
}
}
$scope.addRow = function(){
$scope.entities.push({
d1: Math.floor(Math.random() * 10),
d2: Math.floor(Math.random() * 10),
d3: Math.floor(Math.random() * 10)
});
}
$scope.generateData();
});
<script src="https://code.jquery.com/jquery-2.1.4.js"></script>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.4.5/angular.min.js"></script>
<link href="//cdn.datatables.net/1.9.4/css/jquery.dataTables.css" rel="stylesheet" />
<script src="//cdn.datatables.net/1.9.4/js/jquery.dataTables.min.js"></script>
<div data-ng-app="myApp" data-ng-controller="ctrl">
<table>
<thead>
<tr>
<th>Col1</th>
<th>Col2</th>
<th>Col3</th>
</tr>
</thead>
<tbody>
<tr data-ng-repeat="entity in entities">
<td data-ng-bind="entity.d1"></td>
<td data-ng-bind="entity.d2"></td>
<td data-ng-bind="entity.d3"></td>
</tr>
</tbody>
</table>
<button data-ng-click="destroy();">Destroy</button>
<button data-ng-click="addRow();">Add rows</button>
</div>
I believe the issue is you have your ng-repeat upon the <tr> element. Calling fnDestroy() seems to to delete and re-insert all the original elements in the DOM.
I believe because of this Angular looses reference to the template and it was as if the ng-repeat was never there in the first place. As Angular is not removing and creating the new elements itself. Adding {{entities}} in your markup show that the array is correct and that the new item is being added.
I'm not familiar with data tables so don't know if it has events etc that you need to destroy with fnDestroy() but could you not empty the entities array instead so that angular removes the table? Thus not loosing its bindings? Or will the structure of the table change, different number of headers etc.
EDIT: Found this post on the data tables forums. Apparently you can use the data tables API to manipulate the table, add, remove rows etc. They advise, and i agree, that you shouldn't have multiple libraries manipulating the DOM. One option is to have Angular instruct data tables what to do with the table and let data tables actually manipulate it. You could wrap this in your own minimal directive or service also.
https://www.datatables.net/forums/discussion/21286/datatables-and-angularjs#Comment_61703
I'm in the process of replacing one hell of a lot of javascript/jquery code with knockoutjs and I'm trying to figure out the best way forward. I have no time to replace everything at the same time so I will have to integrate the knockout logic with the existing javascript...
Is there a way to populate a knockout view model from javascript which is not called from a data-bind attribute? Any help would be nice since I've not been able to find this anywhere else (at least not anything that worked).
I know what I'm mentioning here isn't the "correct" way of doing things, but I'm trying to migrate parts of the javascript code... Doing it all in one go isn't an option at the moment.
(using knockout 3.2)
Edit:
Typically the existing javascript does something like:
$('#productlist').append(productItemHtmlCode);
And I would rather have it do something like:
ViewModel.productList.push(productItemObject);
If I understand correctly, currently you have something like this:
<div id='myDiv'>
current status is: <span id='statusSpan'>Active</span>
</div>
with some corresponding javascript that might be something like:
function toggleStatus() {
var s= document.getElementById('statusSpan');
s.innerHTML = s.innerHTML == 'Active' ? 'Inactive' : 'Active';
}
And you want to change it so that the javascript is updating the viewmodel rather than manipulating the DOM?
var app = (function() {
var vm = {
statusText: ko.observable('Active'),
toggleStatus: toggleStatus
}
return vm
function toggleStatus() {
vm.statusText = vm.statusText == 'Active' ? 'Inactive' : 'Active';
}
}) ();
ko.applyBindings(app,document.getElementById('myDiv'));
And then the html would be
<div id='myDiv'>
current status is: <span id='statusSpan' data-bind="text: statusText"></span>
</div>
If that's what you're talking about, that's what Knockout is designed for. The javascript updates the viewmodel, knockout manipulates the DOM.
The example you give is easy to represent in Knockout.
the HTML:
<div>
<table data-bind="foreach: products">
<tr>
<td data-bind="text: id"></td>
<td data-bind="text: name"></td>
<td data-bind="text: category"></td>
</tr>
</table>
</div>
and in the viewmodel:
vm = {
products: ko.observableArray(), // empty array to start
addProduct: addProduct
}
return vm;
function addProduct(id, name, category) {
products.push({id: id, name: name, category:category});
}
etc.
I am using Angular and TingoDB (Mongo) inside Node Webkit for a single page application. However I have a strange problem that I have been unable to resolve.
When I use an object literal (option 2) the data displays correctly in the html page. However changing the code to return data from the database (option 1) the results do not appear on the html page. I have converted both styles of data into the a JSON string to prove consistency and then using the angular.fromJSON to return an object. Both methods return the same JSON string in console.log and before anyone asks I have either Option 1 or Option 2 commented out so both are not running concurrently.
I have copied the JSON string based on the data passed from TingoDB into the console.log and re-entered it into the code below to ensure that no differences between the 2 versions of the data existed without changing any other code, but the problem still persists.
Can anyone shed light on why this occurs and how to fix it?
var app = angular.module('myApp', []);
var Engine = require('tingodb')(),
assert = require('assert');
var db = new Engine.Db('./db', {});
var collection = db.collection("clean.db");
app.controller('tingoDataCtrl', ['$scope', function($scope) {
function getData(callback) {
//Option 1
collection.find().toArray(function(err, docs){
callback (JSON.stringify(docs));
});
//Option 2
var docs = [
{name:"tingo1", description:"56",_id:2},
{name:"tingo2", description:"33",_id:3},
{name:"tingo3", description:"22",_id:4},
{name:"tingo4", description:"76",_id:5},
{name:"tingo5", description:"99",_id:6}
];
callback (JSON.stringify(docs));
}
function info(b) {
// I'm the callback
console.log(b);
$scope.items = angular.fromJson(b)
}
getData(info);
}]);
And the Html
<body ng-app="myApp" id="main">
<div class="page page-data ng-scope">
<section class="panel panel-default" ng-controller="tingoDataCtrl">
<div class="panel-heading"><span class="glyphicon glyphicon-th"></span> Tingo Data</div>
<table class="table">
<thead>
<th class="col-md-4">
Name
</th>
<th class="col-md-8">
Description
</th>
<th class="col-md-8">
ID
</th>
<th></th>
<tr>
</tr>
</thead>
<tbody>
<!-- <tr class="reveal-animation" ng-repeat="item in items | filter:query"> -->
<tr ng-repeat="item in items | filter:query">
<td>{{item.name}}</td>
<td>{{item.description}}</td>
<td>{{item._id}}</td>
</tr>
</tbody>
</table>
</section>
</div>
<script src="js/tingo_problem.js"></script>
</body>
TingoDB is an asynchronous API which will work in the background without stop your app. This means that a syncronous code have no time to wait for an answer and in return it gives undefined.
In your case, you have done a asynchronous call, and it returns correctly the answer to the memory, but too late, the DOM have been updated with undefined already even if your javascript has the data (try console.log to see that it was there).
Angular has a way to be forced to update again the DOM with the new elements of the controller. it is called $apply. And the best way to use it to avoid unexpected behaviours is:
function info(b) {
// I'm the callback
console.log(b);
$scope.items = angular.fromJson(b);
if (!$scope.$$phase) {
$scope.$apply(); //forces update the view
}
}//$scope is NECESARY to be defined in the controler, avoid using it with "ControlerAs"
I have a controller which have a function called $scope.removePoster and another one inside the same controller who create a table calling $scope.removePoster like this:
for(var i=0; i < 6 && postersNum >= 0; i++){
...
table += '<td align="center">';
table += '<img width="150" height="175" src="../js/librerias/carousel/images/'+$scope.posters[indexPosters]['image']+'"><br>';
table += '<button type="button" class="btn btn-danger" ng-click="removePoster('+$scope.posters[indexPosters]['id']+')">Delete</button>';
table += '</td>';
...
When I add this table in my HTML the button doesn't call this function.
Sounds like you are using for something like this:
<!-- HTML -->
<table>
<tr ng-repeat="poster in posters | limitTo: 6">
<td align="center">
Poster {{poster.id}}
<img width="15" height="18"
ng-src="../js/librerias/carousel/images/{{poster.image}}" />
<button type="button" class="btn btn-danger"
ng-click="removePoster(poster.id)">
Delete
</button>
</td>
</tr>
</table>
// Controller:
$scope.posters = [];
$scope.getPosters = function (url) {
$http.post(url, {'method' : 1}).success(function (data, status) {
$scope.posters = data;
});
};
$scope.removePoster = function (id) {
$scope.posters.some(function (poster, idx) {
if (poster.id === id) {
$scope.posters.splice(idx, 1);
return true;
}
});
};
See, also, this short demo.
Some highlights:
By using ngRepeat on the <tr> element, we instruct Angular to create as many tr elements as necessary based on the content of posters (subject to the filtering (see below)).
Angular's built-in limitTo filter, filter's the posters array and makes only the first 6 items available to ngRepeat. Conviniently enough, when the content of the posters array changes (e.g. after removing an entry), the whole expression gets re-evaluated creating or removing DOM nodes as necessary.
IMPORTANT
The implementation above is not the proper way to handle things in all aspects. It is the cleanest/easiset way to allow you to wrap your head around Angular's way of building a table dynamically.
Specifically, in a "real-world app", you should have a service bring the data from the server and inject the service into the controller to let it gain access to the data.
I am new to Knockout and I am building a Simple POC for using knockout to build SPA(Single Page Application).
What I want to do is to show "Business Units" when the app loads and on selection of a business unit show all "Front End Units" under that business unit and on selection of a front end unit, show all "Sales Segments" under that front end unit.
All this will happen in a single page using the same view and the viewmodel will bind the model based on selected business unit or front end unit.
The issue I am facing is that, I have 5 business units that get bound properly first on document ready, but on selection of business unit, the front end units get repeated 5 times each. In this case, I have 2 front end units and each is shown 5 times. Same issue on selection of front end unit.
You can see this issue mimicked in the following jsFiddle sample - jsFiddle Link
Let me know if you can't access the jsfiddle link. In this sample, I have used arrays, but in actual I will be getting the data through async call to the oData service.
This is the view HTML:
<div id="divbu">
<h4 data-bind="text: Heading"></h4>
<ul data-role="listview" data-inset="true" data-bind="foreach: Collection">
<li data-role="list-divider" data-bind="text: EntityName"></li>
<li>
<a href="#" data-bind="click: $root.fnNextLevel">
<table border="0">
<tr>
<td>
<label style="font-size: 12px;">Bus. Plan: </label>
</td>
<td>
<label style="font-size: 12px;" data-bind="text: BusinessPlan"></label>
</td>
<td>
<label style="font-size: 12px;">Forecast: </label>
</td>
<td>
<label style="font-size: 12px;" data-bind="text: Forecast"></label>
</td>
</tr>
<tr>
<td>
<label style="font-size: 12px;">Gross Sales: </label>
</td>
<td colspan="3">
<label style="font-size: 12px;" data-bind="text: GrossSales"></label>
</td>
</tr>
</table>
</a>
</li>
</ul>
</div>
This is the model and view model:
function CommonModel(model, viewType) {
var self = this;
if (viewType == 'BU') {
self.EntityName = model[0];
self.BusinessUnit = model[0];
self.BusinessPlan = model[1];
self.Forecast = model[2];
self.GrossSales = model[3];
} else if (viewType == 'FEU') {
self.EntityName = model[1];
self.BusinessUnit = model[0];
self.FrontEndUnit = model[1];
self.BusinessPlan = model[2];
self.Forecast = model[3];
self.GrossSales = model[4];
} else if (viewType == 'SS') {
self.EntityName = model[2];
self.BusinessPlan = model[3];
self.Forecast = model[4];
self.GrossSales = model[5];
}
}
function ShipmentReportsViewModel(results, viewType) {
var self = this;
self.Collection = ko.observableArray([]);
for (var i = 0; i < results.length; i++) {
self.Collection.push(new CommonModel(results[i], viewType));
}
if (viewType == 'BU') {
self.Heading = "Business Units";
self.fnNextLevel = function (businessUnit) {
FetchFrontEndUnits(businessUnit);
};
self.Home = function () {
FetchBusinessUnits();
};
} else if (viewType == 'FEU') {
self.Heading = results[0][0];
self.fnNextLevel = function (frontEndUnit) {
FetchSalesSegments(frontEndUnit);
};
self.Home = function () {
FetchBusinessUnits();
};
} else if (viewType == 'SS') {
self.fnNextLevel = function () {
alert('No activity zone');
};
self.Heading = results[0][0] + ' - ' + results[0][1];
self.Home = function () {
FetchBusinessUnits();
};
}
}
You can see the complete code in the jsFiddle link.
I have also tried this with multiple views and multiple view models, where I apply bindings by giving the element ID. In this case, one flow from business unit -> sales segment is fine, but when I click on home or back button and I do binding again to that element, I face the same issue. (home and back button features are not done in jsFiddle example).
Let me know if more details are required. I did look into lot of other links in stack overflow, but nothing addressing this particular problem.
Any help is deeply appreciated. Thanks in advance.
The problem here is that you call your ko.applybindings TWICE and there is a foreach binding that iterate within 5 items, therefore the data are duplicated five times.
you should not call a ko.applybindings more than once on the same model.
Your model is always the same even if it's parametrized.
I had the same problem here: Data coming from an ObservableArray are displayed twice in my table
the fact that you have you business logic inside your viewModel is something that could be discussed, and it makes it not easy to fix this.
Make 3 classes, put them in a common model without logic inside. Then once you have applyed the ko.applyBindings once, you just have to modify the array like this:
viewModel.myArray(newValues)
Here is the fiddle with the amended code: http://jsfiddle.net/MaurizioPiccini/5B9Fd/17/
it does not do exaclty what you need but if remove the multiple bindings by moving the Collection object scope outside of your model.
As you can see the problem IS that you are calling the ko.applybindings twice on the same model.
Finally, I got this working. Thanks to #MaurizioIndenmark.
Though I have removed multiple call for ko.applybindings, I was still calling the view model multiple times. This was causing the issue.
Now, I have cleaner view model and I have different function calls for different actions and modify all the data required to be modified within these functions(events). Now, everything is working as expected.
This is how the view model looks now -
function ShipmentReportsViewModel(results) {
var self = this;
self.Heading = ko.observable();
self.BusinessUnits = ko.observableArray();
self.FrontEndUnits = ko.observableArray();
self.SalesSegments = ko.observableArray();
self.Home = function () {
var bu = FetchBusinessUnits();
self.Heading("Business Units");
self.BusinessUnits(bu);
self.FrontEndUnits(null);
self.SalesSegments(null);
};
self.fnFeu = function (businessUnit) {
var feu = FetchFrontEndUnits(businessUnit);
self.Heading(feu[0].BusinessUnit);
self.FrontEndUnits(feu);
self.BusinessUnits(null);
self.SalesSegments(null);
};
self.fnSalesSeg = function (frontEndUnit) {
var ss = FetchSalesSegments(frontEndUnit);
self.Heading(ss[0].BusinessUnit + ' - ' + ss[0].FrontEndUnit);
self.SalesSegments(ss);
self.BusinessUnits(null);
self.FrontEndUnits(null);
};
self.Home();
}
To see the entire working solution, please refer this jsFiddle
Thanks for all the valuable suggestions in getting this work.