[dev] watch code and re-build/upload on changes

[EverlastingBugstopper]

Provide --watch flag and make its default "true"

[dihmeetree]

+1 for this. Testing out the dev feature today and definitely need a re-build/watch feature :)

[EverlastingBugstopper]

The usage I proposed for this might be a bit problematic given our existing choice for wrangler preview. Preview's watch flag does not accept any value, instead it checks for its presence. This means that wrangler preview --watch=false is not valid/equivalent to wrangler preview.

With wrangler dev I think we should default to watching changes, which would mean we would need wrangler dev --watch=false to work properly.

I think the way forward is to change preview's watch flag to optionally accept a value and default to false, meaning wrangler preview --watch=false and wrangler dev --watch=false would both work as expected. The only difference would be that wrangler preview does not watch by default and wrangler dev does. This may also be confusing and we might want to have both of them behave the same way.

Would love some input on this.

[exvuma]

Ideally, I think we would make the same changes to preview and have wrangler preview's default behavior to watch for changes. And add the same option - as we add to dev - to turn watch off.

If changing preview is out of scope and I think it's perfectly fine to have preview and dev have different default behaviors and not restrict the design of dev to that of the preview.

Not sure I see the rationale behind --watch-false and --watch=false. Why did you choose to include both?

[EverlastingBugstopper]

That makes sense - as for the --watch-false that's just a typo, good catch :)

[ashleymichal]

fwiw i think more folks will use dev, and that they will expect it to always watch regardless of the design of preview.

i would put out the challenge to try and articulate the distinct use cases for preview vs dev, i.e. when would i prefer one over the other?

[EverlastingBugstopper]

@ashleymichal ideally you shouldn't have to use preview, but it can be helpful for things like the network tab that haven't been implemented in the dev server. my goal is to fix this shortcoming with #946 and then strongly encourage people to only ever use wrangler dev.

I definitely want to default watch to true for wrangler dev, this question is mostly about consistency with preview