Example of using v2 Parcel API (rebundling) to run dev-server?

[tajo]

I want to you use Parcel v2 API as a part of my bundle tool. It's pretty straightforward for the prod build (just running bundler.run()) but not sure how to set up a dev server.

Should I try to replicate this function?

[DeMoorJasper]

If you just want to add some kind of middleware to the devserver you can utilise the proxy config.

If you want to write a completely custom server however, you'd probably want to make a custom reporter for that. This is the default dev-server reporter: https://github.com/parcel-bundler/parcel/tree/v2/packages/reporters/dev-server

[egriff38]

Okay, so I didn't know the proxy was capable of same-process router proxying, thats super useful. This could work potentially if you already have the server logic available to you, by importing it into the .proxyrc.js file. I understand what you mean when you say it's the opposite. Technically, this could still work with the structure I shared, I would just need to import the backend routing into the frontend proxy. This stands in contrast to the way the project would be structured at build time, where the express server hosts the static assets produced by parcel build as opposed to dev runtime where parcel is itself holding pieces of the express routing. I understand the transition is under most cases transparent, however, it still offers some challenges over the old middleware model

• debugging the express server with the --inspect flag
• injecting ts-node or dotenv via the -r flag. Could be required at the top of the .proxyrc.js file.
• What is parcel's restart policy if a server file is modified? Does it restart the server or are dependencies of .proxyrc.js actually monitored? Should something like nodemon be used with parcel for just the server files?

[DeMoorJasper]

Dependencies of proxyrc are not watched, you probably don't even need it, you can load the server code on each request which removes the need for anything like nodemon as well. It will result in slightly longer request times...

--inspect is not really possible... as that will include all parcel code in this case there's no way to isolate this as far as I know. That's still the same as Parcel 1 I assume?

If you truly want all these things, you probably don't want to run parcel as any kind of middleware or your api as middleware, you probably want to run parcel in watch mode and just have your server/backend serve these files statically. https://v2.parceljs.org/features/cli/#parcel-watch-%3Centries%3E this way Parcel won't conflict with your backend in any way, you have full freedom and experience the same performance and experience as you would in production during development

[egriff38]

I was able to use the inspect flag if I imported the parcel 1 middleware, because the top level process was still started with node directly. I have used parcel in watch mode and honestly I agree with you that it's an easy while effective solution. The major benefit of transitioning from watch mode to the parcel 1 API import was that the parcel process and the express process shared process.env, which meant if I imported or set an environment variable on the server, the same changes would go through in the parcel process that inlines those variables (super helpful in debugging).

I might reinvestigate the API strategy once the docs are more developed.

[DeMoorJasper]

Got ya we're also moving away from inlining environment variables without explicitly defining them as it's a pretty large security risk, so that ease of use might actually change in the future as well for security reasons... we're probably add some flag to enable it again though, a lot of frameworks and tools already do this as it becomes a pretty big issue once you have strict security requirements

About using --inspect you can still do that using node node_modules/bin/parcel --inspect ... if I'm not mistaken but it will be bloated with all kinds of Parcel code.

[mischnic]

I usually do PARCEL_WORKERS=0 NODE_OPTIONS=--inspect yarn parcel .... , though I'm not sure if that's actually helpful in this case