* use different eslint config for es6 and es5
* remove confusing eslint/baseConfig.js & add more eslint setting for es5, es6
* more clear way to run eslint on es5 & es6 file
* seperate ESNext, ES6, ES6 path, and use different lint config
* rename eslint config file & update eslint rules
* Undo yarn.lock changes
* Rename a file
* Remove unnecessary exceptions
* Refactor a little bit
* Refactor and tweak the logic
* Minor issues
* Add a test-only transform to catch infinite loops
* Only track iteration count, not time
This makes the detection dramatically faster, and is okay in our case because we don't have tests that iterate so much.
* Use clearer naming
* Set different limits for tests
* Fail tests with infinite loops even if the error was caught
* Add a test
