Build does not work in IE11, .js files don't get transpiled

[kouts]

• I confirm that this is an issue rather than a question.

Bug report

Vuepress site does not work on IE11, console throws syntax and invalid character errors.
By examining the generated .js files it seems that they don't get transpiled for IE11, e.g there are
still arrow functions present etc.

Steps to reproduce

You can reproduce it with a default Vuepress installation
and you can also view it here
Check for example files generated inside the js dir

What is expected?

Vuepress to be compatible with IE11

What is actually happening?

Vuepress is not compatible with IE11, js files don't get transpiled.

Other relevant information

• Output of npx vuepress info in my VuePress project:
  System:
  OS: Linux 3.16 Debian GNU/Linux 8 (jessie) 8 (jessie)
  CPU: (2) x64 Intel(R) Core(TM) i7-4712MQ CPU @ 2.30GHz
  Binaries:
  Node: 9.11.2 - ~/.nvm/versions/node/v9.11.2/bin/node
  Yarn: Not Found
  npm: 5.6.0 - ~/.nvm/versions/node/v9.11.2/bin/npm
  Browsers:
  Chrome: Not Found
  Firefox: Not Found
  npmPackages:
  @vuepress/core: 1.2.0
  @vuepress/theme-default: 1.2.0
  vuepress: ^1.2.0 => 1.2.0
  npmGlobalPackages:
  vuepress: Not Found

[kefranabg]

Hi @kouts

Did you check if there was already an existing issue that could solves your problem? Please check these issues that might solve your problem.

[kouts]

Thank you @kefranabg, I have already searched for a workaround but haven't managed to find a solution yet. In my opinion, VuePress should work OOB with IE11 without any workaround as also stated by @yyx990803 here.
If that's not the case maybe it should be added in the docs that VuePress doesn't support IE11.

[wesgro]

Ran into this as well. Seeing arrow functions not getting transpiled in the app bundle

[kouts]

Digging a little more into this it seems that the regex defined here doesn't match anything and this results in files not getting transpiled.
Now, replacing the regex with something like

if (filePath.includes('/node_modules/@vuepress/') && filePath.endsWith('.js')) {
  return false;
}

transpiles the files but polyfills required by IE11 seem that are not present.

[meteorlxy]

#2064 can partially fix this issue.

But I found Object.assign is still not polyfilled. Those polyfills are splitted into other bundles, which are not imported by webpack correctly.

Related:

• [Bug Report] Polyfills are not included correctly #1168
• error in iOs 9 safari : SyntaxError: Unexpected keyword 'const'. Const declarations are not supported in strict mode.  #1606