Promise not polyfilled correctly in IE11

[jaydenseric]

In IE11, Promise is not defined in app.js and causes errors every page load:

I don't think the global polyfill attempt here is working:

[jaydenseric]

You can reproduce the problem using the with-custom-babel-config example with next@3.0.0-beta14. There is no issue using next@latest.

[timneutkens]

https://github.com/zeit/next.js/pull/1344/files should work 🤔

[jaydenseric]

Will be a very happy camper once this is resolved; our testing is blocked and downgrading will re-introduce other issues.

[jaydenseric]

Narrowed it down a bit; 3.0.0-beta6 works and 3.0.0-beta8 doesn't. Here's the difs.

[arunoda]

This should not be happening. But I'll check this.

[jaydenseric]

@arunoda Found the exact issue. The difference that caused it was upgrading Webpack to 2.6. Maybe upgrading Webpack would fix it?

[jaydenseric]

Just noticed that for some reason the webpack entry in package.json is missing the ^. This is locking it to 2.6.0 – the patch we need is in 2.6.1.

[ritujain1000]

Seeing the same issue with webpack v3.4.1 in IE11.

ReferencedError: 'Promise is undefined' for verdor.js