* [precommitHook] move to dev script
* [eslint] fix lint error
* [dev/eslint] do simply boolean checks first
* [dev] use shared REPO_ROOT constant
* [dev/File] precompute relative/ext of path
* [dev/eslint] fix relative import
* [dev/eslint] fix typos
* [grunt] remove unused run:eslintStaged config
* [dev/run] only create log if we are going to use it
* [dev/run/isFailError] ensure return value is Boolean
* [dev/precommitHook] use less intermediate vars
