Investigate adding sourcemaps and removing Babel

[cdock1029]

Bug report

Steps to reproduce

1. Use packages that depend on @material/... components
2. Build
3. Observe bundler not finding source files listed in source maps.

Actual behavior

Parcel bundler showing many errors of Could not load source file.... in source map..
because only javascript files are uploaded to npm, but source map is looking for typescript files.

Expected behavior

No error messages polluting the console. The source map is directed to the javascript files or the typescript files are uploaded to npm.

Screenshots

Your Environment:

Software	Version(s)
MDC Web	3.2.0
Operating System	Pop!_OS 19.10

Additional context

parcel-bundler/parcel#2185

#4206

Possible solution

Upload typescript files to npm.
OR, remove sourcemaps

[EstebanG23]

Thank you for reporting. Moving to backlog to add ts files.

[mattmspie]

I recently updated react-scripts in a React project that includes @material/circular-progress. I'm now seeing the following warnings during build, that look the same as this issue:

Failed to parse source map from '<path-sanitized>/node_modules/@material/base/component.ts' file : error : ENOENT: no such file or directory, open '<path-sanitized>/node_modules/@material/base/component.ts'

Failed to parse source map from '<path-sanitized>/node_modules/@material/base/foundation.ts' file : error : ENOENT: no such file or directory, open '<path-sanitized>/node_modules/@material/base/foundation.ts'

Failed to parse source map from '<path-sanitized>/node_modules/@material/circular-progress/adapter.ts' file : error : ENOENT: no such file or directory, open '<path-sanitized>/node_modules/@material/circular-progress/adapter.ts'  

Failed to parse source map from '<path-sanitized>/node_modules/@material/circular-progress/component.ts' file : error : ENOENT: no such file or directory, open '<path-sanitized>/node_modules/@material/circular-progress/component.ts'

Failed to parse source map from '<path-sanitized>/node_modules/@material/circular-progress/constants.ts' file : error : ENOENT: no such file or directory, open '<path-sanitized>/node_modules/@material/circular-progress/constants.ts'

Failed to parse source map from '<path-sanitized>/node_modules/@material/circular-progress/foundation.ts' file : error : ENOENT: no such file or directory, open '<path-sanitized>/node_modules/@material/circular-progress/foundation.ts'

Failed to parse source map from '<path-sanitized>/node_modules/@material/circular-progress/index.ts' file : error : ENOENT: no such file or directory, open '<path-sanitized>/node_modules/@material/circular-progress/index.ts'

As a quick test, I updated the .map files corresponding to the warnings above to change "sources":["filename.ts"] to "sources":["filename.js"] and the warnings went away.

[mattmspie]

@allan-chen Is there a chance this issue and #5904 could be separated and the title restored to "Source maps refer to non-existent source files (.ts)" (i.e. undo your May 12, 2020 edits)? This issue is a bug report whereas investigating a move away from Babel is a more invasive chore. For example, if this issue is restored to focus just on the broken sitemaps, then PR #7506 could actually be sufficient to close this issue.

[mattmspie]

I didn't heard back from @allan-chen on my last comment. Any chance @acdvorak might be able to weigh-in on my request? I see you have done some maintenance of the webpack and typescript configs.

[asyncLiz]

Hi @mattmspie! I believe this issue is obsolete now that we're focusing on Material You. MDC will soon enter maintenance-only mode.

We'll keep this in mind for the Material You components and packaging! We definitely want sourcemaps for them :)

[mattmspie]

@asyncLiz - I appreciate that the focus is on Material You now, but I'd like to ask (beg?) just once more that the original bug reported in this ticket be addressed while the project is still maintained. The original reporter correctly titled this ticket to indicate a bug:

Source maps refer to non-existent source files (.ts)

For projects where warnings are treated as errors during build, this misconfiguration in sitemap generation causes the build to fail. I've had to resort to including a fork of this project just to resolve this problem.

It's unfortunate that @allan-chen revised this ticket to have a much larger scope than the original report, because with the current title of "Investigate adding sourcemaps and removing Babel", I can totally understand reluctance to investigate. If this ticket could be restored to its original title, the bug could be addressed with a single line change: #7506 . Since source maps are currently broken (and lead to warnings during builds where this package is included), disabling sitemaps during tsc should not be a regression.