Fix for TypeScript, adding some tests and fixing typos

[visvirial]

In this PR, I fixed some transformation errors on TypeScript, added WebWorker tests and fixed some other minor issues.

• The variable desideredWrappedSrc seems to be a typo and was renamed to desiredWrappedSrc.
• The execution fails if there are no import statements in the *.worker.(js|ts) files. Fixed.
• Added EchoWorker tests (both for JavaScript and TypeScript) which test the execution of WebWorker transformation.

Known issues (should be fixed in the future):

• The files imported in the *.worker.ts should be a JavaScript file and cannot be a TypeScript file.
• If there is a comment or something which contains the string import, ./utils/stripper.js considers it as a module imports, and outputs a wrong JS string.
  • Try adding a comment // This will import mylibrary. to ./__test__/echoworker.worker.js somewhere. This will throw a SyntaxError.
  • The importRe regular expression in ./utils/stripper.js should be sophisticated, and / or some syntax interpretation should be applied.

(Note: if you encountered an error by executing Jest, please clear your cache using jest --clearCache and / or just using jest --no-cache)

[codecov-commenter]

Codecov Report

Merging #4 (a771f94) into master (636536d) will increase coverage by 0.31%. The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master       #4      +/-   ##
==========================================
+ Coverage   97.56%   97.87%   +0.31%     
==========================================
  Files           3        3              
  Lines          41       47       +6     
  Branches        3        6       +3     
==========================================
+ Hits           40       46       +6     
  Misses          1        1              

Impacted Files	Coverage Δ
utils/stripper.js	100.00% <100.00%> (ø)
utils/wrapper.js	100.00% <0.00%> (ø)
lib/baseworker.js	96.55% <0.00%> (+0.12%)	:arrow_up:

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[astagi]

@visvirial this PR looks awesome! thank you so much! Yeah I opened this repo as a little experimental module, I'm very happy to see contributions and interest on it!

[visvirial]

When will it be merged?

[astagi]

@visvirial I'll check it during the weekend! I'll merge it on Monday and then draft a new release on NPM! Sorry but I'm very busy at the moment! Thank you for the awesome work, let you know asap

[astagi]

@visvirial in the meantime please add yourself to CONTRIBUTORS

[visvirial]

That's okay. I'm not in a hurry but I just wanted to make sure that my PR is surely in a review. Have a nice weekend!

[astagi]

Again, awesome work @visvirial , thank you so much! Version 0.0.4 is now available on npm

• The files imported in the *.worker.ts should be a JavaScript file and cannot be a TypeScript file.

Mmh that's interesting, it's been a long time since I looked at this code last time, also I never tried importing typescript files inside the worker, what's wrong with them?

• If there is a comment or something which contains the string import, ./utils/stripper.js considers it as a module imports, and outputs a wrong JS string.

  • Try adding a comment // This will import mylibrary. to ./__test__/echoworker.worker.js somewhere. This will throw a SyntaxError.
  • The importRe regular expression in ./utils/stripper.js should be sophisticated, and / or some syntax interpretation should be applied.

You're right, import is a reserved word but it can be used in a comment or in a string, I think that a more sophisticated regular expression may intercept it, without diving into syntax interpretation (I suppose you're talking about using AST, right?)

[visvirial]

Yes, I mean some AST should be employed to be more strictly.

However, since that import statement will appear at the beginning of lines, how about appending the letter '^' to the beginning of importsRe in utils/stripper.js? (Note: also dynamic imports like const foo = await import('foo') shouldn't be matched.)

[visvirial]

Uh, this won't work for import statements in a multiple line comments:

/**
import bar from 'bar';
*/

This will match the regex...

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The most reliable and straight forward way, I think, is to force *.worker.ts to include /* __SEPARATOR__ */ as in https://github.com/visvirial/jest-webworker