Expose rendered module code to generateBundle hook

[btd]

This PR contains:

• bugfix
• feature
• refactor
• documentation
• other

Are tests included?

• yes (bugfixes and features will not be merged without tests)
• no

Breaking Changes?

• yes (breaking changes will not be merged unless absolutely necessary)
• no

List any relevant issue numbers:

Description

This fixes issues i created #3458. I would like to use this info for simple analysis and better code size estimations in visualizer plugin.

Let me know pls, if it could be done better.

[codecov]

Codecov Report

Merging #4028 (0823619) into master (85a3724) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #4028   +/-   ##
=======================================
  Coverage   97.47%   97.47%           
=======================================
  Files         192      192           
  Lines        6773     6775    +2     
  Branches     1984     1985    +1     
=======================================
+ Hits         6602     6604    +2     
  Misses         84       84           
  Partials       87       87           

Impacted Files	Coverage Δ
src/Chunk.ts	100.00% <100.00%> (ø)

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[lukastaegert]

Looks good, I think we can include this as it is, especially with the lazy evaluation. The only things missing to me are doc updates: code should be added both to 02-javascript-api.md at line 58 and 05-plugin-development.md at line 339.
Also I think returning null instead of undefined for the tree-shaken case might fit better with other APIs, but this is just my feeling.

[github-actions]

Thank you for your contribution! ❤️

You can try out this pull request locally by installing Rollup via

npm install btd/rollup#expose-rendered-module-code

Once a build has completed, you can load it into the REPL by inserting the CircleCI build number of the ci/circleci: node-v12-latest build into the link below (unfortunately, we cannot auto-update this comment for PRs from forks at this time):

https://rollupjs.org/repl/?circleci=<build_number>

[btd]

@lukastaegert thanks. I added docs and changed type to be string | null

[lukastaegert]

Looks great, thanks!

[btd]

Thank you