Fixes issue #443 by adding prefix to the HarmonyExportExpression model.

[cjweigle]

This attempts to fix the recent regression of builds breaking. @dreyks observed that PR #8039 in the webpack repo caused hard source to fail, and I've tried to balance out those changes in this PR. I was able to run two builds with out having to clear the cache, so that's a good sign.

Hard source is great, thank you for your hard work.

[timneutkens]

The PR this change refers to is this one: webpack/webpack#8042

(just putting it here to go to the webpack side quicker)

[timneutkens]

Seems like at least one of the causes of the test failing is that you have to pin mini-css-extract-plugin to 0.4.0

[connor4312]

Our builds were failing when running cached builds without this PR. Specifically, when compiling i18next in the file dist/es/i18n.js, on the first build the file ends with

__webpack_exports__["default"] = (new I18n());

But on the second build, it ends with...

 __webpack_exports__["default"] = (undefinednew I18n());

I don't claim to have understood the inner workings of this plugin, but manually applying this fix to my local plugin files resolved the issue. It would be fantastic to see it merged @mzgoddard .

[Legym]

Our team saw a 4x boost in lowering compiling times. We are using the latest version of NuxtJS which uses a newer version of webpack. Do we have a potential update to this this PR?

Appreciate all the hard work. Thank you!

[dan-cooke]

Thanks for this amazing plugin guys, the amount of time it saves our team really adds up.

Was just wondering if theres anything I could do to assist with the CI checks?
Eagerly awaiting this merge.

Thanks again!

[Rohit-L]

@mzgoddard Are you still active here? Can we get this merged and released?

[hhaidar]

@chronweigle thanks for doing this

[mzgoddard]

Merged as part of #477