Instead of downloading the file continuously on the client, we can add a progress bar instead. (2) It seems like this causes a page reload, which kills the state of the React application. It doesn't seem right to have to be parsing a request string on the backend. The issue here is two-fold: (1) The request data can be nested and of variable length.

The closest that I found was a script StreamSaver.js but using an external MITM is not acceptable and I don't understand the code well enough to determine whether this is a viable (or even good approach). It does not seem possible to enable this behavior in JavaScript. To have the browser download the file as it's being streamed back to the client. It's a bad experience that the user cannot see any other progress and has no idea whether their request is actually processing or how long it will take. The issue is that it can take several minutes for the request to complete and the user sees a spinning indicator indicating that their request is in progress. Current ImplementationĪn AJAX POST request is sent to the server, it waits for all of the data to come in and then uses createObjectURL to trigger a download. The return format is CSV and there is a decent amount of processing that needs to happen, so this processing processing is done in parallel and then sets of rows are streamed back to the UI.

We are building a UI that allows users to query our data in bulk.

Javascript download file to client