Fix #26

[lxsmnsyc]

• Fix needHmr keeps on failing due to Vite's check for config.isProduction, refer to https://github.com/vitejs/vite/blob/b2d972e53b59329695f74e01893b21ec5c136ffd/packages/vite/src/node/config.ts#L391-L395
• Fix undefined for plugins makes the mergeAndConcat fail when user adds their own plugin.

Resolves #26

[lxsmnsyc]

I might have to re-evaluate the use of config.isProduction. I mean, it works even if the problem is on the user-side, however should we be more consistent with the mode being used rather than the ENV the user chose?

[amoutonbrady]

That change sounds totally fine to me! Thanks :)

As per your question, I reckon I'm not entirely sure I understand what the difference between mode and env is.
As per https://vitejs.dev/guide/env-and-mode.html#modes the env is populated according to the mode the user chose, which seems like what you did take advantage of.

Am I missing something?

[lxsmnsyc]

There's a tiny bit of difference. mode actually derives its own value and I think, it is dependent on how vite is run i.e. vite is development. Meanwhile, env takes .env on a higher priority based on NODE_ENV

[amoutonbrady]

Ah I see! I think for now the priority is to resolve the fact that HMR is not working properly. You solution is totally fine with me. If somehow this not coherent enough, I guess we can take it to the next step and tweak slightly. Thank you again 🙏🏻