Modernize codebase

[maltsev]

The 1st version of htmlnano was released 9+ years ago. Since then, the JS ecosystem has changed a lot. It'd be nice to modernize the codebase so it follows the modern best practices.

Ideas

• Convert to TypeScript
• Remove the Babel build step
• Use modern test runner (vitest?) (mocha is fine)
• Use modern linters (eslint@9 & prettier)

Feel free to suggest other ideas (or even submit PRs)!

[SukkaW]

As a previous active contributor of htmlnano, I am more than happy to help rewrite htmlnano to TypeScript! Just sign me in.

[maltsev]

That would be much appreciated! Thank you!

Just sign me in.

Hereby, I officially grant thee permission to be signed in!

[SukkaW]

• Use modern test runner (vitest?)

TBH, mocha is just fine and we don't need to replace it. It is still actively maintained (last release 2 weeks ago), supports TypeScript (types through @types/mocha and runner through @swc-core/register). With swc, mocha is not slow. Our test case only use less than a second so we don't really benefit more from replacing mocha.

[maltsev]

I think we can consider this issue completed!

[SukkaW]

I think we can consider this issue completed!

I have only converted the source code from JS to TS, but those unit tests are still JS.

I have been busy recently, but I will begin bringing up new PRs again ASAP!