Disable some babel plugins that are now part of goja or are not useful

[mstoykov]

Unfortunatelly babel doesn't let you disable plugins from a preset, so
we need to specify every plugin that we want with it corresponding
configuration.

[imiric]

Should we consider including this along with transform-runtime then? It would add a lot of value to support generators and this poor-man's async, unless they would add a lot to the bundle and explode the memory requirements.

[mstoykov]

I think we discussed this internally and we came to the conclusion that it is better to break all the async/await stuff that is halfway working and letting people do it on their own through the template-es6 or similar.

I removed the generator tests specifically because we were failing practically all of them because it was needing regeneratorRuntime. And I am heavily against adding regeneratorRuntime and reenabling plugins, possibly bringing back the polyfill for Promise. It will likely not work great, again all of those tools are not written for k6 but for nodejs/browsers. Goja does implement Ecmascript faithfully, but there are still possibilities that those tools require something special in one of the cases to work.

Testing this will likely show whether I am correct or not, but IMO "not async" async is not worth the time investment and explanation on why it is not working as someone would expect. And then the possibility of breaking changes once we actually start having real async.

[imiric]

I didn't really dig into each enabled plugin and their configuration, but as long as the TC39 tests pass I think we can be confident that we're not breaking anything.

I like that they're now explicitly listed instead of being part of some obscure preset. Nice work! 👏

[mstoykov]

I didn't really dig into each enabled plugin and their configuration,

The configuration is copied from the presets, which are linked above each section of plugins. So it should be exactly the same but without some of them.

I like that they're now explicitly listed

Yeah, this also means that in the future removing one will be just commenting a line and rerunning the tests. And let's hope we can remove all of them 🍾

[codecov-io]

Codecov Report

Merging #1822 (805c987) into enableAlmostAllTc39Tests (97689ae) will decrease coverage by 0.03%.
The diff coverage is n/a.

@@                     Coverage Diff                      @@
##           enableAlmostAllTc39Tests    #1822      +/-   ##
============================================================
- Coverage                     71.58%   71.54%   -0.04%     
============================================================
  Files                           181      180       -1     
  Lines                         13939    13938       -1     
============================================================
- Hits                           9978     9972       -6     
- Misses                         3328     3331       +3     
- Partials                        633      635       +2     

Flag	Coverage Δ
ubuntu	71.54% <ø> (ø)
windows	?

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
js/compiler/compiler.go	76.47% <ø> (ø)
js/common/initenv.go	86.66% <0.00%> (-13.34%)	⬇️
js/initcontext.go	90.10% <0.00%> (-2.20%)	⬇️
lib/executor/vu_handle.go	93.33% <0.00%> (-1.91%)	⬇️
cmd/ui_windows.go

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