fix(client): revert modern syntax to allow IE11 use

[johnjbarton]

Fixes #3629 #3630

[johnjbarton]

@longlho FYI

[longlho]

hmm also the arrow functions need to be rewritten as well :(

[AppVeyorBot]

✅ Build karma 2879 completed (commit 136526410d by @johnjbarton)

[karmarunnerbot]

✅ Build karma 482 completed (commit 136526410d by @johnjbarton)

[karmarunnerbot]

✅ Build karma 481 completed (commit 136526410d by @johnjbarton)

[devoto13]

I also don't see this fixing anything, which was not fixed in #3629. Or am I missing something?

[johnjbarton]

No, I missed the later commits that fixed updater.js, sorry.

[XhmikosR]

@johnjbarton @devoto13 Shouldn't you all enforce this with ESLint? BTW I personally dislike standard, but you could use standardx to enforce some options.

[devoto13]

@XhmikosR This sounds like a great idea! I'll look into setting up ESLint to fail on >ES5 code in the client scripts. This way we can catch such problems before IE 11 tests are run on the post-commit build.

[johnjbarton]

The IE11 test:client is clearly adequate to this task, if we run that test. The fail here was that the browserstack tests failed on post commit and we did not block the PR commit for the new syntax. The fix is should be to run the test and have it block PRs from merging.

[XhmikosR]

I still think it's just simpler to enforce ES5 in the linting stage, but it's just my 2 cents.