Stale data passed to promiseFn when using watchFn

[salolivares]

Potentially related #4

Issue
When watching for a variable change using watchFn, the react async hook properly re-runs promiseFn but with old props passed in.

Expected
promiseFn should have received the new props on re-run.

Example
See https://codesandbox.io/s/jovial-grothendieck-3xth2
In the example above the first render console.logs the following:

in function  grapefruit 
in promise grapefruit 
in function  grapefruit 
Rerun promise? 
false

All is good! But once we change the fruit, we get the following:

in function  lime 
Rerun promise? 
true
in promise grapefruit  <---- should have been lime
in function  lime 
Rerun promise? 
false

And if we run it again:

in function  coconut 
Rerun promise? 
true
in promise lime    <---- should have been coconut
in function  coconut 
Rerun promise? 
false

Am I missing something with the way hooks work or overlooking something simple? Any help will be appreciated!

[ghengeveld]

Thanks for reporting! This sure looks like a bug with watchFn. I tried replacing it with watch, which works as expected. So if you can make do withwatch (i.e. you have a primitive to watch on), you can use that as a workaround.

Do you want to take a stab at fixing this and open a PR? That would be greatly appreciated.

[salolivares]

I'll take a stab at it! I won't have time this week, but will try to get around it next week. I'll keep ya updated.