Скачать или смотреть How to Keep the Spinner Visible Until Your File Download Completes in Angular

Discover how to ensure your spinner stays active while downloading large files in Angular, even when using services such as NgxSpinnerService.
---
This video is based on the question https://stackoverflow.com/q/71991510/ asked by the user 'Wen' ( https://stackoverflow.com/u/15763116/ ) and on the answer https://stackoverflow.com/a/71995483/ provided by the user 'Keith POON' ( https://stackoverflow.com/u/3755426/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Angular filedownload spinnerService

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
How to Keep the Spinner Visible Until Your File Download Completes in Angular

When developing applications with Angular, particularly when working with file downloads, it's essential to provide users with feedback during potentially lengthy operations. A common issue arises when a spinner or loading indicator disappears too quickly during file downloads, leading users to think the application has stalled or encountered an error. This guide will guide you through the process of ensuring your spinner remains visible until the file download is complete.

The Problem: Spinner Disappears Too Soon

You may encounter a situation where you are downloading a large file, and while the spinner shows initially, it disappears after a brief moment, possibly before the download completes. This can be frustrating for users, as they may be unsure if the download is still in progress.

Here’s the TypeScript function you likely have:

[[See Video to Reveal this Text or Code Snippet]]

In this approach, the spinner is hidden after a successful or unsuccessful response from the file download service, but this can result in the spinner disappearing before the download action is completely processed.

The Solution: Keeping the Spinner Active Until Completion

To ensure that the spinner remains visible throughout the duration of the file download, we need to modify our approach slightly. Specifically, we can wrap the creation of the Blob inside an Observable or Promise and handle the spinning logic within this new structure.

Step-by-Step Solution

Wrap the Blob Creation in an Observable:
This allows us to maintain control over when to hide the spinner, ensuring it remains visible until the entire download process is completed.

Modify the download logic accordingly:
This approach ensures that the spinner service's hide method is only called when the file is fully downloaded.

Here’s how you can modify your function:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

By wrapping the Blob creation in an observable, we can effectively manage the spinner's visibility throughout the file download process. This not only enhances user experience by providing clear feedback during long operations but also ensures your application behaves predictably.

Implementing the above changes will help you maintain a consistent and engaging experience for your users, especially when downloading large files. If you have further questions or need clarification on any points, feel free to reach out!