Ember.js: disappearing component properties while performing acceptance tests - javascript

I have a component listing-table which takes a number of properties, like this:
{{listing-table model=model.devices type='user' exclude='customerName'}}
This works as intended, and the integration tests also work just fine. However, my acceptance tests fail, because apparently my exclude property is not being taken into account while running an acceptance test.
I have tested this by printing to console the value of this.get('exclude') in the component's javascript file and getting undefined. However, printing e.g. this.get('type') yields the expected results.
I have then, for testing purposes, removed exclude and replaced type's value with it, i.e. type='endpointName,typeName', however, I would get the previous value in the console, e.g. user.
This is all way beyond puzzling, and I'd really like to know what's the matter with acceptance test. Any sort of hints are more than welcome, and thanks for your time!
EDIT:
I have now edited my acceptance test to exclude clicking through various elements to get to the route that contains my listing-table component:
From:
visit('/users/1')
click('a:contains("Devices")')
To:
visit('/users/1/devices')
And the test passes. I still don't understand why clicking through makes my component's properties disappear, whereas visiting the page directly works just fine.
EDIT 2:
So, here is some sample code. This is what my test looks like:
test('/customers/1/devices should display 5 devices', function (assert) {
let type = server.create('endpoint-type')
let user = server.create('user')
let endpoint = server.create('endpoint', { type })
server.createList('device', 5, { user })
visit('/customers');
click('a:contains("Customer 0")')
click('a:contains("Devices")')
andThen(function () {
assert.equal(find('.device-listing').length, 5, 'should see 5 listings')
assert.equal(find('th').text().trim(), 'IDModelManufacturerMACExtensionLocation', 'should only contain ID, Model, Manufacturer, MAC, Extension, and Location columns')
})
Now, my Devices table should, in this case, omit the 'Customer' column, however, the column does appear in there, even though my component in devices.show.customers has been invoked with:
{{listing-table model=model.devices type='user' exclude='customerName'}}
My listing-table.js file basically uses this.get('exclude') inside the init () function to process the excludes, but as I said, if I add a console.log(this.get('exclude') in that file, I get undefined.
EDIT 3:
After more testing, I have made some progress, and the resulting question needs its own page, here.

Just a few thoughts:
I assume this one has been done since you got green on your second attempt... are you using andThen to handle your assertions to make sure all of your async events are settled?
Is the model hook being triggered? Depending on how you enter the route, the model hook will sometimes not get triggred: Why isn't my ember.js route model being called?
Might be helpful to have some code to look at.

Related

Observable fires only once

I decided to pick up this RxJS tutorial over the weekend to learn about reactive programming. The goal is to set up a simple page that generates an interactive list of users from the Github users API using Observables.
The list displayed is a subset of the total number of users retrieved (in my case 3 out of 30). The list needs to be refreshable (show a new set of users), and you need to be able to remove entries from it by clicking the 'remove' button on each respective entry.
I've set up a chain of Observables to define the behavior of the page. Some act as events to trigger processing, and some publish processed results for use in the app. This chain should dynamically cause my list to be updated. Currently, the default flow is like this:
Startup!
Suggestions refresh triggered! (this is where the data is retrieved)
30 new suggestions available!
List update triggered! (this is where I choose 3 users to display)
List updated! (at this point, the list is showing on the page)
A list update is triggered on startup, by refreshing the list and by removing something from the list. However, when I refresh the list, this happens:
Refresh button clicked!
Suggestions refresh triggered!
30 new suggestions available!
As you can see, the trigger to update the list of users is not set off. As I understand it, by emitting some value at the start of a stream, the rest of the stream should be executed consequently. However, this only seems to be happening the first time I run through the chain. What am I missing?
You can find a running version of my project here.
I think the issue is in the way userStream$ Observable is created.
Filtering users not closed and then taking the first 3 is something that can be done directly on the UserModel[] array passed into the pipe chain by displayEvents$ via filter and slice methods of Array.
If you do so, you remove the need of using the from function to create an Observable<UserModel> on which you then have to apply flatMap (which is currently better known as mergeMap) to apply finally toArray to transform it back into an Array of UserModel.
In other words you can simplify the code as in the following example, which as side effect solves the refresh problem.
this.userStream$ = this.displayEvent$.pipe(
map(users => users
.filter((user: UserModel) => !this.closedUsers.has(user))
.slice(0, this.numberOfUsers))
// flatMap((users: UserModel[]) => from(users))
// // Don't include users we've previously closed.
// , filter((user: UserModel) => !this.closedUsers.has(user))
// , take(this.numberOfUsers)
// , toArray()
, tap(() => console.log('List updated!'))
// Unless we explicitly want to recalculate the list of users, re-use the current result.
, shareReplay(1));
To be honest though I have not fully grasped why your original solution, which is a sort of long detour, does not work.

How to display a "not found" page with parameterised route in Durandal

I have a Durandal application, and I use router.mapUnknownRoutes to display a user-friendly error page if the URL does not correspond to a known route. This works fine -- if I go to, say /foo, and that doesn't match a route, then the module specified by mapUnknownRoutes is correctly displayed.
However I cannot find any way to display that same error page when I have a parameterised route, and the parameter does not match anything on the backend.
For example, say I have a route like people/:slug where the corresponding module's activate method looks like this:
this.activate = function (slug) {
dataService.load(slug).then(function () {
// ... set observables used by view ...
});
};
If I go to, say /people/foo, then the result depends on whether dataService.load('foo') returns data or an error:
If foo exists on the backend then no problem - the observables are set and the composition continues.
If foo doesn't exist, then the error is thrown (because there is no catch). This results in an unhandled error which causes the navigation to be cancelled and the router to stop working.
I know that I can return false from canActivate and the navigation will be cancelled in a cleaner way without borking the router. However this isn't what I want; I want an invalid URL to tell the user that something went wrong.
I know that I can return { redirect: 'not-found' } or something similar from canActivate. However this is terrible because it breaks the back button -- after the redirect happens, if the user presses back they go back to /people/foo which causes another error and therefore another redirect back to not-found.
I've tried a few different approaches, mostly involving adding a catch call to the promise definition:
this.activate = function (slug) {
dataService.load(slug).then(function () {
// ... set observables used by view ...
}).catch(function (err) {
// ... do something to indicate the error ...
});
};
Can the activate (or canActivate) notify the router that the route is in fact invalid, just as though it never matched in the first place?
Can the activate (or canActivate) issue a rewrite (as opposed to a redirect) so that the router will display a different module without changing the URL?
Can I directly compose some other module in place of the current module (and cancel the current module's composition)?
I've also tried an empty catch block, which swallows the error (and I can add a toast here to notify the user, which is better than nothing). However this causes a lot of binding errors because the observables expected by the view are never set. Potentially I can wrap the whole view in an if binding to prevent the errors, but this results in a blank page rather than an error message; or I have to put the error message into every single view that might fail to retrieve its data. Either way this is view pollution and not DRY because I should write the "not found" error message only once.
I just want an invalid URL (specifically a URL that matches a route but contains an invalid parameter value) to display a page that says "page not found". Surely this is something that other people want as well? Is there any way to achieve this?
I think you should be able to use the following from the activate or canActivate method.
router.navigate('not-found', {replace: true});
It turns out that Nathan's answer, while not quite right, has put me on the right track. What I have done seems a bit hacky but it does work.
There are two options that can be passed to router.navigate() - replace and trigger. Passing replace (which defaults to false) toggles between the history plugin using pushState and replaceState (or simulating the same using hash change events). Passing trigger (which defaults to true) toggles between actually loading the view (and changing the URL) vs only changing the URL in the address bar. This looks like what I want, only the wrong way around - I want to load a different view without changing the URL.
(There is some information about this in the docs, but it is not very thorough: http://durandaljs.com/documentation/Using-The-Router.html)
My solution is to navigate to the not-found module and activate it, then navigate back to the original URL without triggering activation.
So in my module that does the database lookup, in its activate, if the record is not found I call:
router.navigate('not-found?realUrl=' + document.location.pathname + document.location.hash, { replace: true, trigger: true });
(I realise the trigger: true is redundant but it makes it explicit).
Then in the not-found module, it has an activate that looks like:
if (params.realUrl) {
router.navigate(params.realUrl, { replace: true, trigger: false });
}
What the user sees is, it redirects to not-found?realUrl=people/joe and then immediately the URL changes back to people/joe while the not-found module is still displayed. Because these are both replace style navigations, if the user navigates back, they go to the previous entry, which is the page they came from before clicking the broken link (i.e. what the back button is supposed to do).
Like I said, this seems hacky and I don't like the URL flicker, but it seems like the best I can do, and most people won't notice the address bar.
Working repo that demonstrates this solution

Why do I need to call a dynamic route ":_id" and not whatever I want?

Here's a rather standard way to set a route in Iron Router:
Router.route('/posts/:_id', {
name: 'postPage',
data: function() { return Posts.findOne({_id: this.params._id}) }
});
Experimenting around a little, beginner as I am, I tried:
Router.route('/posts/:whatever', {
name: 'postPage',
data: function() { return Posts.findOne({_id: this.params.whatever}) }
});
This works well, up to a point. True, whatever will scoop up whatever is after /posts/ as its value, and the data context will indeed be the same as before... but linking to specific posts now won't work!
So,
{{title}}
simply won't work doing it "my" way (linking to nothing at all).
I can't fully wrap my head around this, and I'm too much of a novice to grasp the source code for Iron Router, so my hope is that someone here can explain it in a manner that even a beginner like me can comprehend.
Preferably like something like this:
First {{pathFor 'postPage'}} looks inside the routes to find the one named postPage.
It sees that this route corresponds to /posts/ followed by something else.
Looking inside the data context it finds that only one post is returned, namely the one with the same _id as whatever comes after /posts/.
It understands that it should link to this post, cleverly setting the url to /posts/_id.
This is wrong, most likely, and it doesn't explain why it would work when whatever is turned into _id. But it would help me immensely to see it parsed in a similar fashion.
Edit: Cleaned up my question so it is easier to grasp.
There's a simple set of circumstances that together lead to confusion:
The Posts.findOne issue is explained by the fact that the first argument can be either a selector or a document _id. So it's not really a shortcut but rather a documented feature.
As you found, putting :something in the iron:router URL causes that value to be reported as this.params.something inside the route function. This also registers something as an parameter to that route, which brings us to how pathFor works.
The pathFor helper takes two inputs: first the name of the route (in this case 'postPage') and second an object of parameters, which can come either from the second argument as in {{pathFor 'postPage' params}} or from the data context like so: {{#with params}}{{pathFor 'postPage'}}{{/with}}.
Now, here's why passing in a document from the database works if you call the parameter _id but not if you call it whatever: the post object that you retrieved from the database _has an _id field, but it doesn't have a whatever field. So when you pass it into pathFor, it only passes along the correct _id if the parameter to the route also happens to be called _id.
Let me know if that makes sense, I agree that this is somewhat confusing and that this "shortcut" hides what exactly pathFor and params actually do.

AngularJS: Changing object does not update field but changing string directly does

I feel like this is something trivial, but I've been stuck for awhile.
I have an object user, set in the directive UserSettings. The directive's element contains a button with html {{user.name}} to open a model for user settings. When the page loads user.name is set.
The user settings form in the modal is contained by a controller called UserSettingsForm. I've been trying to debug the controller and I'm confused by the behavior I'm seeing.
console.log #$scope.user # debug to show user object is there
#$scope.test = angular.copy(#$scope.user) # set test equal to a copy of user
#$scope.test.name = 'wowee' # change test object's 'name' property
#$scope.user = angular.copy(#$scope.test) # set user back to test
console.log #$scope.test # test is changed
console.log #$scope.user # user is equivalent to test
The above debugging works as expected, but the unexpected part (for me, at least) is the fact that {{user.name}} in the nav bar is not being updated. But when I do #$scope.user.name = #$scope.test.name the {{user.name}} field in the HTML is updated.
I am admittedly an angular noob (even though this is probably a JavaScript concept), but the logic I'm having trouble with doesn't make sense to me and I would be very appreciative if someone could clear it up for me, and maybe even give me a push in the right direction as far as properly updating the user object to equal the test object. test will eventually be an instance of the user settings form and only when the data is saved successfully will that instance be saved as user.
Angular is still watching the previous reference, even after you do the change.
If you use:
angular.copy(source, destination)
It will deleted all of the previous properties and replace them with the source properties.
Here's the updated example for your case:
angular.copy($scope.test, $scope.user)
That statement should solve the issue.

Controller belonging to render helper gets reset if passed a model

I noticed a behavior in Ember that does not make any sense to me. I am not sure if this is a bug or feature. In the latter case I am really interested why this is a desired behavior. So here we go:
Make sure you can see your browsers console output.
Open the example project on JS Bin. Notice the two init messages comming from IndexController and FoobarController.
Click on the button saying 'Add one'. Do this so that there is some state on the FoobarController.
Click on the 'Go to hello' link to transition to the hello route
Go back to index via the link
The count variable still has the value. All good!
Now there is a tiny change in the next JS Bin. I pass the model to the render helper.
Follow the steps above again. After step 5 you see that count is 0 now and that the 'init FoobarController' appears again.
Somehow a controller belonging to a render helper gets reset when a model is passed. I can't find any information on why this happens or think of any reason why this makes sense.
From the Docs
If a model property path is specified, then a new instance of the controller will be created and {{render}} can be used multiple times with the same name.
Passing that second param re-instantiates the FoobarController, which basically resets the count to 0, whereas not passing the model param creates a singleton instance of the FoobarController.

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