![]() submit() can be called elsewhere and it still will trigger the "create-user" loading state. You're treating the submit() function like it's tied to the view when it's not. No, defining the key twice is a feature, it's not simply an implementation detail. Is this an actual problem you are running into? This hasn't been a problem for me.Īnother thing, besides your strategy being very good, there is still an effort to define the same key in swIsLoading and in the submit function. It is possible, unintentionally, swIsLoading to have a key and the submit function to add a different key. One way of accomplishing this task, is the Component ( We also decide that, in this case, we do not want to display the same "page loading" progress bar as before. When we do this, we'd like to disable the form's "submit" button and style it to indicate that the form is pending. Next up, we want to let our users create a new User by submitting a user creation form. If () returned a promise (or subscription), we could also pass it to () and achieve similar results. When the observable returned from () emits for the first time, IsLoadingService will know that this observable has stopped loading and update the "page loading" indicator as appropriate. When this component is initialized, ( () ) will be called triggering the "page loading" indicator we set up previously. Seperately (as mentioned before), when IsLoadingService#add() is passed an Observable value, IsLoadingService will take(1) from the value and subscribe to the results. We decide we want to trigger the same progress bar indicator that we just set up to indicate that a page is loading. Having completed the task of adding a "page loading" indicator during router navigation, now we want to display a loading indicator when we asynchronously fetch a list of users from a service. In the case of an Observable value, add() will take(1) from the observable and subscribe to it, noting that loading for that Observable has stopped when it emits it's next value.When passed a Subscription or Promise, add() will automatically mark that the Subcription or Promise has stopped loading when it completes.Note: if we called IsLoadingService#add() with a Subscription, Promise, or Observable value, we wouldn't need to call remove().With this code, our app will now display a loading bar at the top of the page while navigating between routes. When NavigationEnd || NavigationCancel ||NavigationError event is emitted, we say that loading has stopped (via remove()). When a NavigationStart event is emitted, we say that loading has started (via add()). IsLoadingService will emit true from isLoading$() so long as there are one or more things that are still loading.īecause we want to display a loading bar during router navigation, we subscribe to angular Router events.When something has stopped loading, we can call IsLoadingService#remove().To indicate that something has started loading, we can call IsLoadingService#add().We can subscribe to loading state via IsLoadingService#isLoading$() which returns an Observable value indicating if the state is loading or not. The Angular IsLoadingService is a small (less than 1kb minzipped) service for angular that helps us track whether "something" is loading. ![]() When loading is false, the loading indicator will disappear. In this example, we use the IsLoadingService to get our loading state as an observable, save it in the class property isLoading, and subscribe to it in our root component's template. We want to display a loading indicator while navigation is pending.įor our loading indicator example, we will use the MatProgressBar component from the library, and display it along the top of the page.Įnter fullscreen mode Exit fullscreen mode Many (most?) Angular application's will make use of the Angular Router to allow navigation between sections of an app. Allow me to demonstrate using some examples which build off each other (some of the examples are taken from Nils' post). It's a great read, but I don't think any of the options discussed are quite as nice as using the small IsLoadingService I made for this task. I recently read a great post by Nils Mehlhorn talking about various strategies that you can use to display/manage loading indicators. Using wx.html2.A common task for Angular applications is showing a loading indicator during page navigation, or showing a loading indicator while POSTing data to a server, or showing a loading indicator while *something* is happening.
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