Angular 11 error being thrown on IE11 with Storybook 6.1 and 6.2@alpha

[thomasoreilly]

Describe the bug
When bundling for IE11 it appears that code isn't being transpiled.

Two errors are being thrown.
"Const must be initialized"
and
"Syntax error"

To Reproduce
Steps to reproduce the behavior:

1. Create a new application for Angular 11
2. Integrate Storybook 6.1
3. Update .browserlistrc so IE11 is opt-in
4. Open on IE11 browser and view error in console

Expected behavior
Should run successfully.

Screenshots
Example Repo:
https://github.com/thomasoreilly/storybook-angular11-ie11-6.1-issue
Deployment of Repo:
https://thomasoreilly.github.io/storybook-angular11-ie11-6.1-issue/?path=/story/example-introduction--page

Code snippets
If applicable, add code samples to help explain your problem.

System
Please paste the results of npx sb@next info here.

Environment Info:
System:
- OS: macOS 10.15.7
- CPU: (12) x64 Intel(R) Core(TM) i7-9750H CPU @ 2.60GHz
Binaries:
- Node: 12.20.0 - ~/.nvm/versions/node/v12.20.0/bin/node
- Yarn: 1.22.10 - ~/.nvm/versions/node/v12.20.0/bin/yarn
- npm: 6.14.8 - ~/.nvm/versions/node/v12.20.0/bin/npm
Browsers:
- Chrome: 87.0.4280.141
- Firefox: 78.6.1
- Safari: 14.0.1
npmPackages:
- @storybook/addon-actions: ^6.1.14 => 6.1.14
- @storybook/addon-essentials: ^6.1.14 => 6.1.14
- @storybook/addon-links: ^6.1.14 => 6.1.14
- @storybook/angular: ^6.1.14 => 6.1.14
- @storybook/preset-ie11: 0.0.1 => 0.0.1

Additional context
This issue is also happening on the latest alpha for 6.2.

[yannbf]

cc @tooppaaa

[thomasoreilly]

Just tested on the latest version alpha.18 and this issue is resolved.

[thomasoreilly]

Hi @shilman. Is there any plan to hotfix 6.1 for this issue? Has our team in a bit of a pickle as we rely on Storybook for testing and IE11 is crucial for us. If there's anything I can do to help out I'd be happy to help. Thanks.

[shilman]

@thomasoreilly I'll discuss with @tooppaaa and see what's involved. If it's straightforward and not destabilizing I'd be happy to patch it.

[thomasoreilly]

Thanks for the quick response, sounds good.

[shilman]

@thomasoreilly can you kick the tires on this for me? #13741

yarn bootstrap --core
cd examples/angular-cli
yarn storybook

[thomasoreilly]

Hey @shilman.

Just recently installed 6.2 and we are still experiencing this issue with IE11. We are also seeing experiencing this issue on a vanilla Angular setup. Has there been any discussion about IE11 support for Angular and Storybook?