Add bundler picking with optional CLI argument

[michaeldll]

Hey there, thanks for the tool. In my case, I just needed to test for ESBuild tree shaking, but it seems like running the tool automatically checks all three bundlers.
So I added this simple snippet of code to add a CLI argument in the format -r -w -e or any combination of these to add a bundler picking functionality.

[michaeldll]

Note: I'm a novice to node.js, hopefully this is a proper way to do it haha

[CodyJasonBennett]

Thanks for the PR. I'll want to prefer full names to prevent clashes (e.g. Rolldown in the future), but I'm curious what use-case you're targeting solely ESBuild for. Would you prefer a programmable API from a maintainer perspective or are you using this to track down troublesome dependencies as a user?

[michaeldll]

Meant to answer earlier, sorry for the delay.

Anyways, no problem, thanks for your reply. I agree that full names is a better option, I'll add it.
Of the two use-cases you mentioned, mine is closest to tracking down troublesome dependencies as a user.
Basically, the script stopped working as soon as I ran it because it threw an error while checking for Rollup. I therefore wanted a way to avoid errors in other bundlers and just check for the one(s) I use.

Hopefully that makes sense!