Modernize (decaffeinate + rollup)

[aminya]

Description of the Change

This pull requests updates underscore-plus without changing the API:

• decaffeinate: src code is converted to Modern JavaScript
• Rollup: underscore-plus is built with rollup which makes it load much faster
• Tree shaking: now underscore-plus is tree shakable. It uses named exports which allows other tools like Rollup to tree-shake it, similar to the original underscore
• babel: uses babel for conversion to cjs
• Enhances the performance and loading time (in the next PRs I will continue this)

Verification Process

Tests are untouched to show backward compatibility! As you see all of them pass.

Applicable Issues

Release Notes

• decaffeinate: src code is converted to Modern JavaScript
• Rollup: underscore-plus is built with rollup which makes it load much faster
• Tree shaking: now underscore-plus is tree shakable. It uses named exports which allows other tools like Rollup to tree-shake it, similar to the original underscore
• babel: uses babel for conversion to cjs
• Enhances the performance and loading time (in the next PRs I will continue this)

[aminya]

@lkashef I updated underscore-plus to be faster. 😉

[lkashef]

Hi @aminya, I think the main purpose here is decaffeination, so I am wondering if the performance enhancement could work on their own for ease of review and also following this template that is more relevant to performance enhancement PRs

[aminya]

Hi @lkashef!

Yes, I did not change any source code here. The performance improvement is a side effect of decaffeination! To be able to use import/export and optional chaining (to keep it near to CoffeeScript) I hade to use Rollup and Babel. I did not change any source coded in this pull request, this all is just to make the automatic decaffeination nicer. These changes start from this commit

Commit-messages show this as well. Each commit-message is like:

name of the function + the change made to make automatic decaffeination nicer

I have kept my performance improvement ideas for separate pull requests. Let me know if you have questions, I can explain about each commit if it is needed.

[Aerijo]

@aminya There are decaffeinating tools like this that will handle translating things like optional chaining. Introducing a Rollup dependency can be split into a separate PR, as can the other script / CI changes.

[aminya]

@aminya There are decaffeinating tools like this that will handle translating things like optional chaining.

Hi @Aerijo!

This pull request is already done. I added optional chaining support to decaffeinate myself in this pull request 😄 I used the same thing.

Introducing a Rollup dependency can be split into a separate PR, as can the other script / CI changes.

Rollup allows using import ... from ... and export * from. That is necessary for the functionality of this pull request. Otherwise, this will not work. The changes related to Rollup are minimal. They are in these two commits:
ce2a05e
f69f260

[Aerijo]

I'm not sure I follow; are you saying the current CoffeeScript code cannot be translated into correct JS code? Or just that you want to use a specific import syntax, etc., which is not supported yet without transpiling? If the latter, my point above is that this can be split into multiple steps: decaffeinate, and then introduce Rollup, etc. Decaffeinating in and of itself is a straightforward change, but if you tie it with the other changes then it can't be accepted unless the new dependencies are also accepted.

[aminya]

are you saying the current CoffeeScript code cannot be translated into correct JS code?

No. I said this is already translated.

Or just that you want to use a specific import syntax, etc., which is not supported yet without transpiling? If the latter, my point above is that this can be split into multiple steps: decaffeinate, and then introduce Rollup, etc.

I want to use import-export, and without that, the transformation should be done using babel instead of rollup which generates a slow code. I used rollup here for import/export transformation, which transforms those without any runtime cost. If separating these two commits is what you want, I do not mind separating them, but that will have a performance regression for the current PR.

[Aerijo]

I do not mind separating them, but that will have a performance regression for the current PR.

Only because you've bundled a performance enhancement in this PR though, right? When compared to the library's current state there should be no significant impact.

Adding a PR to enhance performance is great, I don't have an opinion one way or another on it (though I'm not responsible for reviewing and merging one). But like what @lkashef mentioned, decaffeinating is already a big (if straightforward) change in and of itself, so would benefit from having it's own PR. And to be clear, when I say decaf, I mean into "plain" JS, without introducing Rollup or Babel. You can always make a followup PR to introduce the import ... syntax using one of those tools.

[aminya]

The decaffeinate subset of this pull request is created here: #22