Q'n'A

Vite

Does Vite allow to set several modes simultaniosly?

No, in short. There is no infrastucture to handle several modes.

$ vite build --mode development --mode https

This way it won't work. The last argument will rewrite the whole value. And what is more important, the wariables from the .env.development won't be read automatically.

$ vite build --mode development,https

Will set mode variable as a "development,https" string and every time where you need to use either mode or import.meta.env.MODE you have to transform into something you are ready work with.

Of course, those issues could be overcomed, if needed

mode string could be parsed and the envs can be stored within import.meta.env as separate variables, use src/env.d.ts and config.define
vite provide loadEnv helper, to ready easily any env file from within the vite.config.ts module

Does Vite perform the typechecking on typescript code?

No, though, that isn't an issue at all. To make sure the code is correct we can call the tsc --noEmit beforehand the build.

Does Vite able to to split big files on chunks automatically?

Maybe, but it doesn't. It shows the warnings and provides seversl strategies to split the codebase on smaller pieces

(!) Some chunks are larger than 500 kBs after minification. Consider:
- Using dynamic import() to code-split the application
- Use build.rollupOptions.output.manualChunks to improve chunking: https://rollupjs.org/configuration-options/#output-manualchunks
- Adjust chunk size limit for this warning via build.chunkSizeWarningLimit.

How to make experimental customisation of env variables on local machine?

Create a file env/.env.<mode-name>.local put there the variables you need. They will be merged over the variables from the .env.<mode-name>.