How can you reset Knockout for each Jasmine test? - javascript

I have some feature tests that run with a fixture (loaded with jasmine-jquery) that has some Knockout bindings in the HTML. At the begin of each test I want to start with a viewModel in its initial state.
If I call applyBindings() in the beforeEach() with a new instance of the viewModel I get this error from Knockout
Error: You cannot apply bindings multiple times to the same element.
If I try to revert the properties of the existing viewModel to match its initial state I still get an error. I believe this is because the fixture's HTML is removed after each test - this probably breaks the bindings?
I've also tried a suggestion that came up when Googling which was to use the cleanNode function in Knockout. This isn't part of the API (it only designed to be used by Knockout internally) and no matter what I tried it didn't resolve the issue.
It feels like I'm taking the wrong approach to this. tl;dr; How does everybody else test Knockout with Jasmine?
Thanks for any help

I generally append an element in beforeEach, apply bindings to that element, and ko.removeNode on it in afterEach. Something like:
var fixture;
beforeEach(function() {
fixture = document.createElement("div");
document.body.appendChild(fixture);
});
afterEach(function() {
ko.removeNode(fixture);
});
Then use fixture as the second argument to any applyBindings calls like: ko.applyBindings(myTestViewModel, fixture);

The way I solved this was changing my js to check for jasmine e.g.:
if (!window.jasmine)
ko.applyBindings(viewModel);

Related

Protractor - Giving "could not find testability for element" error when accessing element

I'm running into issue with Protractor when accessing variable that stores return value of "elements.all". I'm fairly new to Protractor, so I wasn't sure how to select elements by custom attribute. Luckily, I received a suggestion, when I posted a question in another post. I was suggested to try out - "element.all(by.css('[mycustom-id]'));". But I'm not sure if that statement works or not since I'm getting "Could not find testability for element" error. It is also possible that I'm incorrectly iterating the object. I appreciate if anyone of you can point out my mistake. Thanks.
Spec.JS
var settings = require(__dirname + '/setting.json');
describe('Protractor Demo App', function() {
var target = element.all(by.css('[mycustom-id]'));
beforeEach(function() {
browser.get(settings.url);
});
it('Test mouseover', function() {
// This does not work
target.each(function(item){
//Do some stuff here
});
// This does not work either
target.count().then(function(x){
console.log("Total--" + x);
});
});
});
index.html
<div>
<a mycustom-id="123" href=''>HELLO1</a>
<a mycustom-id="211" href=''>HELLO2</a>
</div>
I'm getting this error because I need to set useAllAngular2AppRoots to true in config file. So if anyone having similar issue, make sure you have useAllAngular2AppRoots set to True.
It's not a good practice to put things outside of Jasmine functions, i.e. outside of it(), beforeAll() etc. Protractor uses those Jasmine functions to manage the control flow.
So I'm guessing that it is trying to create those webElements way before it should be. Move your element locator inside the it() block.
it('Test mouseover', function() {
var target = element.all(by.css('[mycustom-id]'));
target.each(function(item){
//Do some stuff here
});
});

jQuery-Chains in an AngularJS $timeout

Am I mistaken or is AngularJS' $timeout function buggy when it comes to jQuery-Chains (in this case jsTree)?
An exception is raised
$.(...).jstree(...).on is not a function
This is my snippet:
$timout(function() {
$("#foo").jstree().on('select_node:jstree', onSelect)
});
When not chaining the .on() but having it in an extra line like
$("#foo").on('select_node:jstree', onSelect)
there is no exception beeing thrown and the onSelect works fine.
Any hint is much appreciated!
you must download jstree and include that your project
https://github.com/vakata/jstree/zipball/3.2.1
Overview
Include a jsTree theme
Setup a container
Include jsTree
Create an instance
Listen for events
Interact with your instances
$(selector).jstree() returns an instance of $.jstree.core, and not a jQuery wrapped object.
Thus, you cannot chain it with the .on() handler setter - problem is completely unrelated from Angular / timeout issues of course.

Unable to retrieve cached jQuery selector in AngularJS service

I am having a little trouble hiding an element. I am attempting to hide this element using an AngularJS service. My code is as follows:
app.service('testService', function(){
var testElement = $("#testElement");
this.hideElement = function(){
testElement.hide();
}
});
The code above does not actually hide the element, but the following code does:
app.service('testService', function(){
this.hideElement = function(){
var testElement = $("#testElement");
testElement.hide();
}
});
However, I have multiple functions that use the testElement and I would hate to have to keep declaring it in all the functions that need testElement within the service. Am I doing something wrong here?
Am I doing something wrong here?
Yes. In fact your very first step was wrong. I mean having service that makes some DOM manipulations, in your case hiding HTML node. Services are data manipulation layer (retrieve, transform, save, post, etc.) but never presentation one, it should not care about View. Services are reusable piece of application code, meaning that it is supposed to be injected in different places of the app to provide a bridge to data sources, it should not make any view transformations, it's just not what they are for.
You should use directive for this with controller as mediator to decide when and what to hide and show. Most likely it will be enough to use build-in ngShow/ngHide directives with some boolean flags set in controller.
for html manipulation better to use angular controllers or inbuilt directives. services are never recommended.
If you really want to cache something, use simple JS Constants or html5 localstorage if you cache session wise use sessionstorage, they are really helpfull. or in angular $rootscope variables are also global.
Yes. What actually happened when you assign 'testElement' outside the hide method was 'testElement' will be assigned with undefined value.Since injection are created before the dom was available.So the below code doesn't work.
var testElement = $("#testElement");
this.hideElement = function(){
testElement.hide();
}
For DOM manipulation it is better to go with directives than services.

Use directive as value for ng-if?

In my application, I need to be able to easily determine whether a user is authenticated within my HTML and in all templates.
My first thought on how to do this was to create a "global" controller and apply it to which simply set $scope.isAuthenticated = $auth.isAuthenticated.
However, after doing some reading, I discovered that this wasn't considered good practice. Instead, I created a directive, which would just return $auth.isAuthenticated().
angular.module('HordeWebClient')
.directive('isAuthenticated', function($auth) {
return $auth.isAuthenticated();
});
And then in my templates, I figured I could just use .... This doesn't work, the element isn't rendered regardless of the state of $auth.isAuthenticated.
The Safari error console doesn't show any problems, so I'm stuck on where to start in fixing this. Any pointers would be greatly appreciated.
In my opinion you should use .run on your main module.
angular.module('app').run(function(){
if(!isAuthenticated){
redirectToLoginView();
}
});
More: https://docs.angularjs.org/guide/module

Since Meteor upgrade to 0.8.0, Template "rendered" callback is not fired when Session variable dependancy changes

I'm stuck with a problem since I upgraded to 0.8.0.
The Template rendered is not being fired anymore (except the first time).
I followed the recommendations as in:
https://github.com/avital/meteor-ui-new-rendered-callback/blob/master/new2/client/each.js
This didn't helped, and so I finally made this small piece of code (by modifying the new2 example).
The main difference is that the update is triggered by a Session variable change instead of a DB change.
This perfectly shows the problem, as rendered is fired only twice with this example:
client/each.js
Template.list.items = function () {
return (Session.get('items') || 'None')
};
var renderCount = 1;
var logRender = function () {
console.log("rendered #" + renderCount);
renderCount++;
};
Template.list.rendered = function () {
logRender();
};
Template.justName.rendered = function () {
logRender();
};
setInterval(function () {
Session.set('items', {name: Random.choice(["one", "two", "three"])});
}, 1000);
client/each.html
<body>
{{> list}}
</body>
<template name="list">
{{#with items}}
{{> justName}}
{{/with}}
</template>
<template name="justName">
{{name}}
</template>
How can I do to get the Template.justName.rendered callback properly fired when content update is triggered by a Session.set?
Thanks,
I do have an instant solution for you, but it probably requires a tiny bit of re-thinking your actual code. This is by the way the same problem as here:
Meteor 0.8.0 - Failed to operate DOM in rendered callback
But the question is posed in such a different context that it makes sense to answer it twice.
So why does it not trigger the rendered callback? Because it does not re-render.
Blaze treats the whole thing of "how to react on a changed dependencies" very differently, "better" one might say: it will identify the DOM node where your "one", "two" or "three" (in your case it's the template itself) was stored in and just replace the part that has changed, which is the text content "one", "two" or "three". The DOM node itself as well as the template stay completely intact. That also means, that everything you could have been doing with this DOM node won't have to be re-done in almost every practical scenario. I.e. if you animate it, change it's text color using jQuery, the color and animation will just stay on the screen, so you won't need the rendered callback to re-do that.
In your case, the problem is easily solved by just rearanging what you want to do on "rerender":
var whatever = function(){
// whatever you want to do on data-change, in your case calling "logRender" (which needs to be renamed with Blaze, anyway..)
logRender();
}
And then the only thing you have to do is firing it whenever your data change, either manually, like this:
setInterval(function () {
Session.set('items', {name: Random.choice(["one", "two", "three"])});
// calling the function when changing the data, knowing that it WON'T destroy the DOM node it affects
whatever();
}, 1000);
or reactively, like this:
Deps.autorun(function(){
Session.get("items"); // our dependency, just has to be there, but you can also use it
whatever(); // will be fired whenever dependency changes
});
The core idea is to eliminate the need to re-do something you did in the rendered callback, since the DOM and the identity of its objects (and all the beautiful jQuery effects) are still intact. So all that is left to re-do is something that only would depend on the particular reactive data-change, which is why there is the Deps.autorun().
In your particular example, your "logRender" function did not have any reactive dependencies, but if you add some and put it into the Deps.autorun(), it will be reliably re-run whenever the dependency changes.
As a conclusion, Meteor 0.7.x and below drove us to make the mistake of treating the "rendered" callback function as a general purpose autorun function, which is why we are running into trouble now and have to fix our apps.
As noted in the comments, this is a indeed a design change with Meteor.
Prior to Meteor 0.8, a template was a function that generated HTML. This function would be re-computed whenever any of its reactive dependencies changed, which resulted in a recreation of all the DOM nodes generated by the template (apart from any sub-templates or isolated nodes). Whenever this re-draw happened, the rendered callback was triggered.
This behavior creates quite a performance hit because it requires re-rendering of potentially a lot of HTML, including for identifiers and helpers depending on data that hadn't changed. Additionally, it made it difficult to use other libraries like jQuery to modify the DOM elements that were created, because Meteor basically had control of the entire process and the jQuery code would have to be carefully re-run each time.
Meteor 0.8 fixes this by only rendering the pieces of the DOM that have actually changed, down to the granularity of the identifiers in your template - it is much more fine-grained. As a result, the template's rendered callback is only triggered once when your template hits the page, and is never called again afterward. This solves a lot of performance issues and allows jQuery and other DOM manipulations to work seamlessly with Meteor, but also means that you won't get the automatic callback signalling when something has changed. You can, however, achieve this with helpers that use reactive variables for specific things that change.
For a more detailed listing of how Spacebars, the new Handlebars replacement, works, see https://github.com/meteor/meteor/blob/devel/packages/spacebars/README.md
See also the new documentation about the rendered callback: http://docs.meteor.com/#template_rendered
So, I was doing a lot of digging yesterday to try and figure out basically the exact same issues you are having. I am still digging, but I did come across this Devshop Talk about Integrating Other Clientside JS Libraries. In it Ted Blackman describes a package he made to trigger events when a Session variable changed. It sounds like what you need. This talk was given prior to 0.8.0 so I am not sure how the package would be effected, but it might be worth a shot.
Devshop Talk - https://www.youtube.com/watch?v=NdBPY98o6eM
Session Extras - https://atmospherejs.com/package/session-extras
Event Horizon - https://atmospherejs.com/package/event-horizon

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