React component doesn't update when using Fable.

[nojaf]

Hi,

I'm using Fable to create my React app. Fable will transform F# code to JavaScript.
I noticed that changes to my compiled code don't get picked up by Snowpack, changing the text doesn't update the screen for example.

I made a small repo to demonstrate the problem: https://github.com/nojaf/snowpack-fable-bug
There I compile script.fsx to src/bin/script.js.
Now changes to the Moon component are not being picked up by Snowpack or at least not the hot reload in the UI part.
Changes to the Sun component are being picked up as expected.

Now I'm wondering why that is?
You can try this out without actually compiling the F# script, changes to the strings in the src/bin/script.js also illustrate the problem.

[FredKSchott]

If fable's compiler changes src/bin/script.js every time you make a change to script.fsx, then that should be getting detected. You can confirm this by looking for "File Changed" output in the dev console. You should see that message every time a file changes to show whether Snowpack detected the change.

[FredKSchott]

Bah sorry, I immediately re-read the part about Sun vs. Moon and realized that this was an HMR thing.

I have no idea why this would be happening, but it seems like an error in the React team's react-refresh. If you don't need it, I'd recommend just removing that plugin.

It's a bit of a pain to replace the default CSA app scripts, you'll need to update the Snowpack config file and the babel config file. This will get easier once #1137 gets merged in the next few days.

[nojaf]

If you don't need it, I'd recommend just removing that plugin.

Well I would like the HMR to work so I'm guessing I'll look around in the react-refresh direction.
Thanks for the pointer.

[FredKSchott]

No problem. to be clear, HMR still works just fine without that update, you just won't get the special "Fast Refresh" features on top of HMR, to do things like preserve component state across updates.

[nojaf]

Thanks for pointing that out.

[nojaf]

I'm checking with the Fable people as they are aware of the problem in general.
We can close this here.