Currently the Cloud9 IDE uses ESLint for linting purposes within the editor, but doesn't read configuration from
.eslintrc files within the project yet.
There should be
On Cloud9 hosted workspaces, .jslintrc is working. I have just added my own rules after reading this post and it was working well.
It seems to be sufficient to set the rules, that should be changed from the default linting configuration in c9.
Wanted to make a comment to answer above, but too low on reputation :(
Seems like eslint config in package.json files (using eslintConfig field) is not handled (yet).