4099 ES6 Refactor lib/HotModuleReplacementPlugin

[KTruong008]

What kind of change does this PR introduce?

ES6 Refactor of HotModuleReplacementPlugin

Did you add tests for your changes?

Tests were already written.

Summary

Issue:
#4099

Other Information

Still working on this PR but I'm a bit stuck and looking for any advice. I managed to fix a lot of the broken tests as a result of the refactor, except for the last few that all seem to stem from the same problem.

All of the broken tests say something along the lines of "TestCases all-combined chunks .... should compile", along with red text underneath:

Unexpected token: keyword (const) [bundle.js:218,16]

I tried changing everything from const to let just to see how it would go, but then it had issues in the same test file with 'chunkId'.

Does anyone know how to run this specific test (TestCases.test.js all-combined) instead of having to run the whole test suite, so I can better debug it?

I tried $(npm bin)/mocha --grep TestCases, but it takes longer to run that single command than it does running the whole test suite because it keeps pausing and giving me weird messages like this:

HEAD 2881ms ± 306ms [2742ms; 3020ms]
․ v3.0.0-rc.2 2973ms ± 338ms [2820ms; 3127ms]
․․ HEAD 1462ms ± 90ms [1431ms; 1493ms]
․

[sokra]

const chunkId -> var chunkId

This is code which is in the generated bundle. The generated code should not contain higher ES.

[sokra]

don't refactor the generated code.

[KTruong008]

stopped refactoring the generated code on line 156

[webpack-bot]

@KTruong888 Thanks for your update.

I labeled the Pull Request so reviewers will review it again.

@sokra Please review the new changes.

[sokra]

  2) TestCases all-combined chunks context should compile:
     Error: Errors while compiling:

bundle.js from UglifyJs
Unexpected token: punc ()) [bundle.js:726,35]

It looks like there is more generated code in ES6 format.

This is how to find it:

• run the test locally: mocha -g "all-combined chunks context"
• open the file test/js/all-combined/chunks/context/bundle.js
• check the line from the error bundle.js:726,35 -> line 726, column 35
• find the origin of the generated code in the HotModuleReplacementPlugin (or paste it here)
• change back to ES3 code.

[webpack-bot]

Thank you for your pull request! The most important CI builds succeeded, we’ll review the pull request soon.

[webpack-bot]

It looks like this Pull Request doesn't include enough test cases (based on Code Coverage analysis of the PR diff).

A PR need to be covered by tests if you add a new feature (we want to make sure that your feature is working) or if you fix a bug (we want to make sure that we don't run into a regression in future).

@KTruong888 Please check if this is appliable to your PR and if you can add more test cases.

Read the test readme for details how to write test cases.

[sokra]

2. TestCases all-combined chunks context should compile:
   Error: Errors while compiling:

bundle.js from UglifyJs
Unexpected token: punc ()) [bundle.js:726,35]
It looks like there is more generated code in ES6 format.

This is how to find it:

run the test locally: mocha -g "all-combined chunks context"
open the file test/js/all-combined/chunks/context/bundle.js
check the line from the error bundle.js:726,35 -> line 726, column 35
find the origin of the generated code in the HotModuleReplacementPlugin (or paste it here)
change back to ES3 code.

Sorry, I was wrong. It's all fine now.

[sokra]

Thanks