Right now we can't properly eslint shiftered files (MDL-54889), I just found unicorn. Which sounds promising..

From its dev guide:

The current build system is Shifter. It have not had any change or improvement in long time. The decision was to create our own build tool.

The scope of the project is to create a new build tool that is backward compatible with Shifter but faster and easier to maintain.

The tool is a nodejs module that can be executed through command line or imported by another module.

Features:

• Wrap the code with YUI().use(), YUI.add() or nothing depending on the module configuration.
• Rollup creation.
• Linting with JS linter (JSHint or ESLint) and CSSLint.
• Minification for JS, CSS and i18n files.
• Watch functionality to build on changes.