Issue 3692 - Add arrow-parens ESLint rule

eslint-config-eyeo/index.js

Index: eslint-config-eyeo/index.js
diff --git a/eslint-config-eyeo/index.js b/eslint-config-eyeo/index.js
index 279f857bdab7cd5a1cbadf9f46dd825de4d7a7ea..844407777d1f3db3d39f75abe4d32763b82b9f0a 100644
--- a/eslint-config-eyeo/index.js
+++ b/eslint-config-eyeo/index.js
@@ -26,6 +26,7 @@ module.exports = {
   },
   rules: {
     "array-bracket-spacing": "error",
+    "arrow-parens": "error",

[Wladimir Palant, 2017/03/02 10:03:29]

Going through adblockplus and adblockpluscore repositories, the use of
parentheses for single-parameter arrow functions is inconsistent with a tendency
towards no parentheses. I think this might be the result of my personal
preferences changing over time. In adblockpluschrome no parentheses are being
used very consistently.

I don't really see a case for enforcing parentheses from our existing codebase.
I also don't see how it improves readability or prevents bugs. So this is
clearly NOT LGTM to me. My preferred solution would be to leave this rule out
and keep allowing personal preferences here since they don't affect anything. If
we want this to be uniform however, I'd vote for the "as-needed" setting.

Maybe Thomas can help me understand how this is going to improve the quality of
our code.

     "arrow-spacing": "error",
     "block-scoped-var": "error",
     "block-spacing": "error",