🐛 Restore pre 1.2.1 RegExp format, make fully Win compat + less greedy

[depoulo]

Sorry for the confusion 😢

There were a few things going wrong here:

When looking at /node_modules\/(?!(deps|go|here))/ (as of d4d4985), I thought the surrounding slashes were meant as path delimiters (obviously not matching on Windows systems). But I was wrong - those are the RegExp delimiters (the slash in the middle however is a path delimiter).

What that also means is that src/traverse_node_modules/walker.js will match and as such be excluded from transpilation (however, on a Windows machine, src\traverse_node_modules\walker.js won't), just as /node_modules/p-debounce-es5/index.es5.js will be transpiled if the matched deps include p-debounce, as it will match the RegExp.

As of such, my "Windows compatibility" change (9926325, #13) was just plain wrong. If anyone using the according release copies the RegExp and fixes it (by wrapping it in forward slashes or new RegExp('')), it will still work, and be even a bit more specific, in that the above file will no longer match, but projectRoot\node_modules\p-debounce\index.js will now match on a Windows machine. Oh actually it won't since I failed to escape the backslash correctly.

The ultimate solution, however, is to put path delimiters ([\\/] to work in both Windows and POSIX-compatible environments) around node_modules and after the module name (but still inside the negative lookahead). This will remove all theoretical false matches. That is what I'm doing in this pull request, alongside re-adding the surrounding forward slashes to make it a real JavaScript RegExp.

Personally, I'm doing like this:

(package.json)

"postinstall": "sh -c \"yarn --silent are-you-es5 check -r . | tail -n 1 > ./non_ES5_node_modules \"",

(webpack.config.js)

exclude: forLegacyBrowsers
  ? new RegExp(
      fs
        .readFileSync(path.resolve('./non_ES5_node_modules'), 'utf-8')
        // remove surrounding RegExp delimiter slashes and trailing newline
        .slice(1, -2)
    )
  : /[\\/]node_modules[\\/]/,

[obahareth]

Hey @depoulo thanks for the fix, but I see the regex you put is [\\\\/], shouldn't it be [\/\\]?

[depoulo]

Well escaping backslashes is an issue on its own, see the xkcd I linked somewhere. What counts here is the script's CLI output, and that should be correct now.

[depoulo]

(Basically it's one backslash for the Windows path delimiter, another one to escape it for the RegExp, and two more (one for each) since we're inside a string.

[depoulo]

(The forward slash doesn't need to be escaped inside a character group)

[obahareth]

Hey @depoulo what I was asking before is because you're matching against \ twice.

I was suggesting [/\\] instead to match against either a forward or backward slash.

Does Windows put two consecutive backward slashes?

[depoulo]

Quoting https://xkcd.com/1638/:

Actual backslash, for real this time

see #16 (comment)

[obahareth]

Thanks again @depoulo, I'll publish a new version later today!

[depoulo]

You're welcome, and I have to thank!