Importing babel/polyfill crashes ie11

[babel-bot]

Original issue submitted by @Ashot-KR in babel/babel#9456

Importing @babel/polyfill crashes IE.

Build environment

• Node/npm version: node v10.15.0, npm 6.7.0
• MacOS 10.13.6

[zloirock]

@Ashot-KR please, add a reproducible example.

[Ashot-KR]

import 'core-js' crashes ie.
IE 11.0.9600.16384 on Win7 crashes
but IE 11.0.10240.17443 on Win10 is OK

Steps to reproduce:
Generate project with create-react-app

npm create-react-app test-project

add import 'core-js' on the top of src/index.js file

[Ashot-KR]

@zloirock https://jsfiddle.net/bpzv9o7x/ fiddle with core-js from cdn

[zloirock]

It works fine on IE 11.0.9600.18665 on Win 7, I have no ideas where I can test it on 11.0.9600.16384.

[nicolo-ribaudo]

@Ashot-KR Did is starter throwing recently? If yes, could you try to understand in which version?

[Ashot-KR]

looks like reason somewhere in core-js/modules/es6.weak-map.

It works fine on IE 11.0.9600.18665 on Win 7, I have no ideas where I can test it on 11.0.9600.16384.

I'm the lucky one 😄 Could it be an IE bug? 🤔

[zloirock]

It's definitely IE bug.

If it's exactly in core-js/modules/es6.weak-map, most likely it's the detection of support frozen WeakMap keys.

Could you replace this condition to true and run it again?

[Ashot-KR]

Could you replace this condition to true and run it again?

@zloirock it stop crashing with true condition

[zloirock]

@Ashot-KR could you try it with this bundle?

[Ashot-KR]

@zloirock looks like it's ok
https://jsfiddle.net/bpzv9o7x/1/