I have some data on a model that comes in the form of a code such as "US60" and "US70".
I need to take that value and show a display value such as "US 7day/60hour" and "US 8day/70hour". I'm not sure if there is any best practices way to do this in Angular, and I'm not having much luck googling it.
What I would do is have a service that I pass in type and value, and it would return a display value, but as with many things in Angular, since this is my first Angular project, I don't know if it's a good way to do it or not.
I'm just needing to use the display value in html such as {{settings.cycle}} I am already able to access the variable, but I want to show the display value, not the actual value.
If I am getting the gist of your question correctly, you have the value available but want to alter how it is displayed on screen right?
There are two main approaches to do this in Angular, using a directive or a filter.
A filter is basically like a pipe in Unix. You can alter a value before it is being displayed. For example:
{ username | uppercase } will transform the username into an all-caps username. Naturally, you can define your own filters for your use case. Filters are mostly used to transform single values. So for your case, a filter sounds best.
A directive is commonly used to create entire components on a page. For example: <user-profile-card></user-profile-card> would be transformed, using the directive, into the appropriate html/css/logic. So these are used often for larger transformations which involve logic, like server requests. Still these directives could also be used for very small components.
So for your case, although what you are actually want to do is not completely clear to me honestly, a filter seems to be your best shot ;)
Related
Which of these two is better?
<span translate="key">Key</span>
or
<span>{{'key' | translate}}</span>
They are both good and work fine but in first case I must fill the content of the element.
Using the attribute is better performance-wise, especially if you intend to use translations on elements that will be inside ngRepeats. This is because the way filter work internally.
Every time there is a digest cycle, angularjs reloads all the expressions containing filters. This is because angular can't possibly know if a filter has changed or not. What this means is that, even if the key of the translation has not changed, but some other value on the scope has, angular will look through every translation and translate it again, just to come to the conclusion that they all remain the same.
Attributes are smarter, because the developer of the directive has explicit control over when it should re-render and what watcher should be created.
Edit: And as far as I know, there is no need to fill the content in the first use-case. You can just leave it empty.
Started with Angular and Protractor.
It just feels wrong to write some heavy css selectors which will break instant when you change something.
Using ID's would make testing way easier.
I'm not using any id attribute for styling yet. Are there any drawbacks using ids for testing I haven't considered?
The general rule is to use IDs whenever possible assuming they are unique across the DOM and not dynamically generated. Quoting Jim Holmes:
Whenever possible, use ID attributes. If the page is valid HTML, then
IDs are unique on the page. They're extraordinarily fast for
resolution in every browser, and the UI can change dramatically but
your script will still locate the element.
Sometimes IDs aren't the right choice. Dynamically generated IDs are
almost always the wrong choice when you're working with something like
a grid control. You rely on an id that is likely tied to the specific
row position and then you're screwed if your row changes.
Also, in general try to use the "data-oriented" approach: by.model, by.binding, by.repeater locators, or if you rely on class names, choose them wisely: do not use layout-oriented classes like .col-xs-4 or .container-fluid.
See also these related topics:
Best Practices for Watir and Selenium Locators
best way to detect an element on a web page for seleniumRC in java
I'm trying to use a single controller for two parts of a large form. I've successfully done this with one controller, but another refuses to work in both parts.
To explain how I did this. I created two directives which pull in separate templates for vehicle information. Make, model, body type and so on. The custom tags are as follows:
<my-sale-vehicle-form ng-controller="vehicleFormCtrl as sale_vform"></my-sale-vehicle-form>
<my-trade-vehicle-form ng-controller="vehicleFormCtrl as trade_vform"></my-trade-vehicle-form>
As you can see each uses the vehicleFormCtrl controller as an alias allowing me to display data from each alias and load data from the controller into the form fields.
Now I figured if this will work I should be able to display multiple instances of a custom warranty form using the same technique as seen below. I attempted it, but I can't seem to get it to work in the same way. I've checked over the templates and each refers to the right alias. Usually what happens is that one will work, or neither will work. If I remove the second instance the first will work. I just can't wrap my brain around why this works in one situation and not the other. I do not get any errors in the console either. Any advice is appreciated. Thanks.
<my_pack0-warranty-form ng-controller="customWarrantyFormCtrl as custwarforma"></my_pack0-warranty-form>
<my_pack1-warranty-form ng-controller="customWarrantyFormCtrl as custwarformb"></my_pack1-warranty-form>
Got a webapp I'm building in Angular.
This app walks a user to authorizing accounts, presenting specific instructions based on the users choices.
I've implemented this as HTML that is shown or hidden based on values in the model, so for 3 different choices, I have 3 different sets of HTML sections that are similar but with different texts.
In the spirit of DRY, I should instead have one set of HTML sections, and instead switch the text based on the values of the model. This means putting text data inside the model, including small snippets of markup, like anchor and strong tags.
Does putting presentation data into the controller violate the principals of Angular?
There are quite a number of options to avoid repeating code depending on what you are looking to do. The following ideas are things I would consider and use when they make sense (I placed these from simple to complex, so you probably can skip the first few):
ng-bind -- Put it on a span/div. Simple & works to bind the model to the display
ng-switch, ng-if, ng-hide, ng-show -- Work to conditionally show an element
custom directive -- use this when you want to alter the behavior of an element or if you want to alter the dom based on a template. If you use "ng-transclude" the contents of the element you template will be included in the result. This can be very elegant but it works best when you have a single format. I can provide examples but angular's documentation also has excellent examples.
service -- I generally use this just to provide data only. This could be via a restful api and $resource or via $http calls. Either way, I wouldn't recommend doing much more than load/save data here.
$scope method -- In other words:
$scope.myMethod = function(x,y,z) { /* code making decisions based on the model */ }
Then you can call this method from one of the previous either via a prebuilt directive (ng-show, etc) or via a custom directive that manipulates the dom for how you expect it to be.
ng-bind-html -- Last option I know to suggest is to use this directive combined with the $sce service to bind whatever you want to the DOM. If you are binding something with angular code in it - make sure to use the $compile service as well. I generally don't favor this approach except as a last resort because it makes it harder to find where elements in the DOM are coming from and it can make debugging + testing a real pain. That said, these tools wouldn't exist if people didn't need them.
I'm sure that this isn't complete and maybe others have suggestions but that is where I would start. Best of luck!
I would put the text data in a separate angular service. This article gives an example: http://joelhooks.com/blog/2013/04/24/modeling-data-and-state-in-your-angularjs-application/
Then if you decided at some point to move it to some other storage, your service would still be the single access point for the rest of the app.
I think the vagueness of the question is part of the problem, so my real first question is, what do you call, in Angular, the thing.
The thing I'm trying to name is the view plus the controller, over the model of a single object. I don't even know what to call it. For things I know ahead of time I'm going to need, I've been creating directives, but what do you call one instance of the thing that a directive creates?
I have several situations where all of a sudden (in response to some external event), I have a new object in the model and I want to show it on the screen. Angular seems to want me to list all the possible views ab initio in their parent view, but that isn't really reasonable in my case. How, for example, would I list all the pop-ups and tool-tips and other stuff.
I'm down in some little edge case, deep in the controller code, and it needs to add something to the current view. What's the accepted practice.
Incidentally, the $route/ng-view is one case of exactly this. The view containing the ng-view, and the ng-view DIV itself, have no idea what the $route module is going to put in the ng-view. I need the more general case of this strategy.
EDIT
People keep asking for an example. How about this: I'm making an equipment-requisition app. When a user asks that one of the 1000 different type of equipment be sent to him, I need to display a pop-up that gathers addition information specific to that type. If he asks for a screwdriver, the pop-up will ask about blade size, neck length, and handle composition; if he asks for an airplane, it will be a wizard ask him about engine size, fuel tanks, seating arrangement. All the app knows on start-up is the list of all equipment types, and the name of the UI element that gathers all subsequent information about each particular type.
I'm down in some little edge case, deep in the controller code, and it needs to add something to the current view. What's the accepted practice.
Somewhere, you need to define all of the views you'll need -- e.g., all of the equipment popups. You could put each view into a separate file and use ng-include to dynamically pull in the one you currently need to display. Define a property on your $scope (e.g., $scope.equipmentTypeViewUrl), then
<div ng-include src="equipmentTypeViewUrl"></div>
Since ng-view can only appear once per page, ng-include is probably not what you need to use if you need multiple levels of routing.
See also
create a single html view for multiple partial views in angularjs
https://groups.google.com/forum/#!topic/angular/xIIyGpW8KUk/discussion
App design using Angular js
Client Side Template with view per role
I think the problem is that you think that you need to create the "thing" in controller, but actually you don't. The way two-way data binding works is that you change some attribute value, and the view changes based on that. I've never seen a use case where that's not enough, pop-ups and tooltips notwithstanding.
However, if you really must have the controller show something, you could utilize angular's events to do that. You would need two parts: a directive responsible for showing stuff (modifying DOM), and the controller. The controller would $broadcast an event with some parameters, and the directive would listen to those events using $on and react accordingly.
I'd just make sure I had some useful code coming in as the model...
<div class="row" ng-repeat="attribute in attributes">
<div class="widget" ng-repeat="input in attribute.inputs">
<input type="{{input.type}}" ng-model="input.value" />
</div>
</div>
I'm extremely limited in my knowledge, but all I know is if you have a definite structure to your model you can build a view that reacts to it dynamically.
If all of those things are related to your original object (properties or in some way other) you could loop through the data, display the properties and if need use the keys and filters for a label. Imho it's not really an angular question, more one if your data structure. If you have a good data structure you could use a service for creating a related data-object.
For a related popup, you can use a directive and even process the model data there (only recommended if it has a consistent structure).
If you dislike this approach, you can process the data directly in the template.
But without more specific details, there will be no definite answer.