My project was building as CJS, then ESM, then CJS again

[rhengles]

During the build, Vite-ssg compiles my project in a folder /.vite-ssg-temp/.

At first, it was building as CommonJS and there was no error.

Then, for some reason (maybe updating some dependencies), it started compiling into an ESM format.

This caused many errors and I had to monkey-patch many packages to make the build work.

Now, out of nowhere, it started building again as CJS! I had to remove the changes I did to the packages to make the build work again.

My question is, how does Vite-SSG decides what module format it uses when building a project?

Edit: Ugh, now it's even worse. When running vite (dev), I have to patch the modules. But when running vite-ssg build, the modules must be unaltered, which means I have to reinstall the modules to build locally.