Replace yargs with commander to reduce dependencies

[AlynxZhou]

Summary

Replace yargs with commander, which is only used in bin/precompile. This PR does not break command interface, because they have the same logic and options.

Both yargs and commander can implement the same options for bin/compile, but commander pulls in 0 dependency while yargs pulls in 11 dependencies directly and maybe many others indirectly.

It seems most users of nunjucks use it as an library, not a cli-program, and they may not like many dependencies pulled in by yargs in their projects (like me).

Checklist

I've completed the checklist below to ensure I didn't forget anything. This makes reviewing this PR as easy as possible for the maintainers. And it gets this change released as soon as possible.

• Proposed change helps towards purpose of this project.
• Documentation is added / updated to describe proposed change.
• Tests are added / updated to cover proposed change.
• Changelog has an entry for proposed change (if user-facing fix or feature).

[nikku]

If you really want to go lightweight, consider going for mri instead of commander.

[AlynxZhou]

No, I am not talking about lightweight, commander has 0 dependency while yargs has a lot, that's enough. Also I noticed that last commit of mri happens one year ago, so maybe it's not good to use it instead of commander now. I am not familiar with mri, so I won't replace commander with it. Sorry.

…

On Wed, Mar 4, 2020, 22:16 Nico Rehwaldt ***@***.***> wrote: If you really want to go lightweight, consider going for mri <https://packagephobia.now.sh/result?p=mri> instead of commander <https://packagephobia.now.sh/result?p=commander>. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#1253?email_source=notifications&email_token=ACANVR2WBK3HDC5D325QAA3RFZPFXA5CNFSM4JHFLT5KYY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGOENYBQHI#issuecomment-594548765>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ACANVR3NQCTR4UTTD3ATD3TRFZPFXANCNFSM4JHFLT5A> .

[nikku]

mri is a drop-in replacement for yargs in most cases and it is zero dependency, too.

[AlynxZhou]

mri is a drop-in replacement for yargs in most cases and it is zero dependency, too.

Thank you for your advice. I'm just not familiar with mri, and I am familiar with commander, so I write patch with what I can do better. I'm just not sure whether I can make patch with library that I never use.

Last commit of mri happened in Dec 24, 2018, it makes people unsure whether it's still maintaining. Also when we refer to 0 dependency command-line arguments parser, commander has been used widely, but mri is not compared with commander. That's the reason why I choose commander.