It's unfortunate that this hasn't been fixed, but at least we've got some ideas that work! It just makes the semantics of getting them a bit more elegant. Thatwont workwhen theProductServiceis actually making requests of a remote server. Why is this still not a thing? @kamilmysliwiec Can you help implementing this async-provider-loader for Angular? I ended up fetching only dynamic config required for services (mainly endpoint config stuff) and for those services, which had already been loaded in forRoot(), called an "updateConfig()" method on them in the "initialize" service after the fetch. This however does not work for me for some reason and it never receives the emitted event. ConfigService should have config object ready to use, which is not true. Already on GitHub? Typescript: When to use it? For example: There is no concept of initialization. Once unpublished, this post will become invisible to the public Hi @projectX21 I think well need more information to assist you, are you using the APP_INITIALIZER to get the LOCALE data and set in your project? Open theProductServicefile and import theObservableandofsymbols from RxJS. This is exactly what I use.
https://docs.angularjs.org/api/ngRoute/provider/$routeProvider. I can only imagine that with time they will appear many more use cases because observables are everywhere so, to me, it makes perfect sense to make angular provide built-in support for these scenarios. We definitely need some kind of "silver bullet approach" for this kind of issues. Hi guys! Fair warning for when you attempt to upgrade. We're a place where coders share, stay up-to-date and grow their careers. The text was updated successfully, but these errors were encountered: Having exactly this problem currently! I would LOVE to see this feature! Async is for when you want stuff to happen while other stuff is waiting to happen, so if that is not the scenario here, then don't use async. We extraced the relevant code into an own service and made replaced the specific promises inside our services with a more or less declarative configuration. In case you want to forbid clients to use the constructor, and force them to go through your factory method, you can also declare the constructor as private. +1 on this, being able to create objects that can't be created until runtime that are asynchronous in nature would be a huge help. I've seen quite a few other users trying to accomplish the same thing on Stackoverflow. Another way to work around this, at least until angular actually support async providers is to inject a value object, which then gets updated using Object.assign(valueObj, serverResponse). It's messy, but it's a reliable option until we get something better: and then use a more normal service creation strategy. Built on Forem the open source software that powers DEV and other inclusive communities. One thing you can do is have an initialized promise on each service: You do not have permission to delete messages in this group, Either email addresses are anonymous for this group or you need the view member email addresses permission to view the original message. @Cassidie How has this approach been working out for you? By clicking Sign up for GitHub, you agree to our terms of service and The previous version assigns an array of products to the componentsproductsproperty. One way is to use an asynchronous init method, which will need to be called by the client. Change other methods with Asynchronous Signature, Awesome Charts in Angular 13 with ng2-charts, Client-Side PDF Generation In Angular 13 With PDFMake, Dynamically Add Title and Meta Tags on Route Change in Angular, Integrate Google Analytics with Angular | Angular SEO. This is the relevant part in my forRoot() providers[]. Use a resolve in your initial route config. we had similar issues and solved them like you described with dedicated initialization promises for some services. I see.
Till now, we have created the getProducts(), getProduct(), addProduct() and deleteProduct() product in ProductService. What I'd like is to have a phase in which I initialize serviceB, loading its state and having it fully functional again, and only then allow serviceA to be able to use its API (after having loaded, Once all the state is loaded and the services are "initialized", only then should controllers access them - at which point I'd like the API to be used in a. I'd still rather see framework level support for this. generally, not everything has to be configured to support the initial loading of the app. './app/core/interfaces/app-config.interface', './app/core/services/env.service.provider', // This gets the environment from a javascript file. In my case my init's are async because the user is going to stare-at/use an old cache'd copy of data/views/etc until any new data is silently updated in the background. The above method likely forfeits some browser resource loading / work parallelism by making everything wait for the config so early in the bootstrap processing, before other work might get started. Although promise chaining indeed solves the problem is requires my service's API to be async, which, in my case it really shouldn't be. A solution to this would also promote real re-usable Angular libraries. In my experience it is particularly a problem when using Ngrx Effects. There are many solutions. This will eventually resolve the promise with the response.data.
Of course if there would be some async function to call (e.g. I've tried many different amalgamations and permutations to try to resolve the races consistently, but nothing works consistently as fetching before the application loads in the main.ts -- something that no longer is supported by PWA applications, so I need another solution. I just gave up on this a week ago. This lets them get a 50ms to 1000ms head-start on using my application without them realizing it's an old copy, and they don't have to wait for a sync update before using it either. Because we are returning the last promise in the chain, our resolve will not conclude until every single promise in the chain has resolved, so this should handle any sort of dependency structure. Have you run into any race conditions at module load time? Updated on September 15, 2020, DigitalOcean Kubernetes: new control plane is faster and free, enable HA for 99.95% uptime SLA, // each post will have a title and category,
https://docs.angularjs.org/api/ngRoute/provider/$routeProvider. I can only imagine that with time they will appear many more use cases because observables are everywhere so, to me, it makes perfect sense to make angular provide built-in support for these scenarios. We definitely need some kind of "silver bullet approach" for this kind of issues. Hi guys! Fair warning for when you attempt to upgrade. We're a place where coders share, stay up-to-date and grow their careers. The text was updated successfully, but these errors were encountered: Having exactly this problem currently! I would LOVE to see this feature! Async is for when you want stuff to happen while other stuff is waiting to happen, so if that is not the scenario here, then don't use async. We extraced the relevant code into an own service and made replaced the specific promises inside our services with a more or less declarative configuration. In case you want to forbid clients to use the constructor, and force them to go through your factory method, you can also declare the constructor as private. +1 on this, being able to create objects that can't be created until runtime that are asynchronous in nature would be a huge help. I've seen quite a few other users trying to accomplish the same thing on Stackoverflow. Another way to work around this, at least until angular actually support async providers is to inject a value object, which then gets updated using Object.assign(valueObj, serverResponse). It's messy, but it's a reliable option until we get something better: and then use a more normal service creation strategy. Built on Forem the open source software that powers DEV and other inclusive communities. One thing you can do is have an initialized promise on each service: You do not have permission to delete messages in this group, Either email addresses are anonymous for this group or you need the view member email addresses permission to view the original message. @Cassidie How has this approach been working out for you? By clicking Sign up for GitHub, you agree to our terms of service and The previous version assigns an array of products to the componentsproductsproperty. One way is to use an asynchronous init method, which will need to be called by the client. Change other methods with Asynchronous Signature, Awesome Charts in Angular 13 with ng2-charts, Client-Side PDF Generation In Angular 13 With PDFMake, Dynamically Add Title and Meta Tags on Route Change in Angular, Integrate Google Analytics with Angular | Angular SEO. This is the relevant part in my forRoot() providers[]. Use a resolve in your initial route config. we had similar issues and solved them like you described with dedicated initialization promises for some services. I see.
Till now, we have created the getProducts(), getProduct(), addProduct() and deleteProduct() product in ProductService. What I'd like is to have a phase in which I initialize serviceB, loading its state and having it fully functional again, and only then allow serviceA to be able to use its API (after having loaded, Once all the state is loaded and the services are "initialized", only then should controllers access them - at which point I'd like the API to be used in a. I'd still rather see framework level support for this. generally, not everything has to be configured to support the initial loading of the app. './app/core/interfaces/app-config.interface', './app/core/services/env.service.provider', // This gets the environment from a javascript file. In my case my init's are async because the user is going to stare-at/use an old cache'd copy of data/views/etc until any new data is silently updated in the background. The above method likely forfeits some browser resource loading / work parallelism by making everything wait for the config so early in the bootstrap processing, before other work might get started. Although promise chaining indeed solves the problem is requires my service's API to be async, which, in my case it really shouldn't be. A solution to this would also promote real re-usable Angular libraries. In my experience it is particularly a problem when using Ngrx Effects. There are many solutions. This will eventually resolve the promise with the response.data.
Of course if there would be some async function to call (e.g. I've tried many different amalgamations and permutations to try to resolve the races consistently, but nothing works consistently as fetching before the application loads in the main.ts -- something that no longer is supported by PWA applications, so I need another solution. I just gave up on this a week ago. This lets them get a 50ms to 1000ms head-start on using my application without them realizing it's an old copy, and they don't have to wait for a sync update before using it either. Because we are returning the last promise in the chain, our resolve will not conclude until every single promise in the chain has resolved, so this should handle any sort of dependency structure. Have you run into any race conditions at module load time? Updated on September 15, 2020, DigitalOcean Kubernetes: new control plane is faster and free, enable HA for 99.95% uptime SLA, // each post will have a title and category,
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I also tried EventEmitter and emit true at the end of the constructor work when the initialization is done while subscribing to it in the Component OnInit function. Currently developing futuristic smart-device, IoT connected, highway construction site safety system in EU. As a result, when I load my application I'd like to be able to "initialize" my services with their previous state (taken from the indexDB), which is an async opertaion. The closest I've come is: But APP_CONFIG is not populated early enough and services loaded from my CoreModule or components that need DI injection of the token need it before it is ready and no matter what I try, I can't seem to get an architecture that makes them wait long enough. Press J to jump to the feed. The only thing I see is something like this: Have a look at this plugin: https://github.com/philippd/angular-deferred-bootstrap. Now subscribe this method in ProductDetailComponent as shown below. :(. yeah, this is what i ended up doing, it seems like this is the easiest every time i think of this situation. A service is just a singleton object returned by a factory function you registered in a module. For example, if you are creating a class to encapsulate some calls to a specific API, you might want to, in the constructor, authenticate to the API to get a fresh token that you will then be able to use in your API calls. In 99% of my use cases, i let angulars automatic promise resolution handle this. I'm curious what kind of feedback I'd get. Once it hits 0 you are ready to go. A community for the awesome MVC JS framework.
I cannot believe this has been an issue for so long! These services receive the base url for all the endpoints with a token. In this tutorial, we will update ProductService.getProducts()which will return anObservablein part because it will eventually use the AngularHttpClient.get() method to fetch the products andHttpClient.get()returns anObservable. I can post a sample if anyone's interested.
as shown below. Client implementations can use the short version, ie: but, if for some reason they need to call the constructor and the init method independently, they can still do so, bypassing your factory method. Still no other solution other than using fetch.
I cannot believe this has been an issue for so long! These services receive the base url for all the endpoints with a token. In this tutorial, we will update ProductService.getProducts()which will return anObservablein part because it will eventually use the AngularHttpClient.get() method to fetch the products andHttpClient.get()returns anObservable. I can post a sample if anyone's interested.
as shown below. Client implementations can use the short version, ie: but, if for some reason they need to call the constructor and the init method independently, they can still do so, bypassing your factory method. Still no other solution other than using fetch.
The workaround is to have some setup(config) function in the service that is called from an app_initializer to make use of async factory but I prefer the first option, it's more cleaner. Put your services in a dedicated module and hook the run event, make the run function depend on your services and initialize everything you need here. @maplion I haven't ran into any issues with the approach. Love podcasts or audiobooks? Would love ideas on AOT. The assignment occurssynchronously, as if the server could return products instantly or the browser could freeze the UI while it waited for the servers response. For a one time download (resolved from the home view I'm assuming) that's needed across multiple views, I have taken to dropping the now resolved and delivered data file (presumably .json) into Session Storage. I need to initialize a module with configuration, and unfortunately even with @gmaughan's approach, those modules were imported before the code ran. I'm not presently using Angular, but am using its injection functionality via inject-js. Specifically to my case, we are using a 3rd party library with services that expect to receive configuration data as Injection Tokens. Just wanted to voice my +1 for this as well. #20383. }}); in a multi-tenant application, the fbkeyid-dynamicvalue should be retrieved server side, asynchronously. The same is true for all DI APIs, such as Injector.get() - they would have to return a Promise because the resulting instantiation might be async. The obvious solution would be to introduce async provider initialization. Needs more up votes. But isn't the initial problem most developers come up with when talking about asynchronous providers that they are looking for a way to initialize some setup parameters before module imports are processed? After too many hours im frustratingly giving up. to your account. Other issues that would be well served by async providers: https://docs.angularjs.org/guide/migration. @maplion I've been using a solution I mentioned above in PWA applications successfully for a while now. Here's a plunk which demonstrates the problem: https://plnkr.co/edit/plWAT5i5BFtjastSdaVy?p=preview. It will become hidden in your post, but will still be visible via the comment's permalink.
, How to deal with inferred TypeScript types and stop using any, Implement Hybrid Decorator Functions in TypeScript. We have an Angular 6 Library that is just domain services that I want others in the org to use. I want to have finished ConfigService with ready to use config file and then provide InjectionToken via using this ConfigService. That is, you can provide APP_CONFIG with an InjectionToken> and await the promise where the config is needed, or use APP_INITIALIZER to block the whole bootstrap process until the config is available. Agree, probably the best way to go. This will not work in a real app. What I'm trying to achieve is to create global @Injectable Service that has some initialization function that needs to finish before the Service should be used.
NestJS (which is a node.js backend framework yet similar to Angular) supports asynchronous providers[1], and it is a highly praised feature. Components may want to render a loading indicator, play animations, and give other signals to the user that they're currently blocked. Some version of the above solutions get me most of the way there, but my APP_CONFIG token injections get called before it is loaded because the modules load things that need it prior to the process completing -- or some other form of race condition. In theHTTP tutorial, we will callHttpClient.get()which also returns anObservablethat emitsa single value, an array of products from the body of the HTTP response, Now you will get the error in the ProductsComponent as. You signed in with another tab or window. I see no other option but to use a window object (script src="appsettings.js") , because that WILL be available and its the only way i can think of keeping the config separate without too much hassle. The key point here is that I want to avoid having to expose async APIs all around due to a singleasync operation required onlyat bootstrap. I see the point. thank you!! // now we can subscribe to it, whenever input changes, // listen to data as long as groupPosts is undefined or null, https://ng-musing.firebaseapp.com/three-ways, https://github.com/chybie/ng-musing/tree/master/src/app/three-ways. This asynchronous approachwill workwhen theProductServicerequests products from the server. I think it would be great to be able to do something like: (notice the useAsyncFactory idea to tell ng that it should wait on the promise, and use the value it produces as the service) Most of the modern approaches are around Observables and hence it makes sense to also update the way we create our providers. #19448 Notice the problem is that another service will read from the ConfigService before it's truly finished being "constructed" IMO, since we need to construct the object, and then finish initializing it's state the APP_INITIALIZER step. See this StackOverflow answer for details. Sign in See the related discussion in #17606 (comment). , [1] https://docs.nestjs.com/fundamentals/async-providers, Just ran into this issue today. appId: 'fbkeyid-dynamicvalue' I do not want to inject ConfigService into other stuff until it's fully constructed and ready to be used - in other words, until the asynchronous request to the server has completed and my ConfigService has all the values populated into it.
NestJS (which is a node.js backend framework yet similar to Angular) supports asynchronous providers[1], and it is a highly praised feature. Components may want to render a loading indicator, play animations, and give other signals to the user that they're currently blocked. Some version of the above solutions get me most of the way there, but my APP_CONFIG token injections get called before it is loaded because the modules load things that need it prior to the process completing -- or some other form of race condition. In theHTTP tutorial, we will callHttpClient.get