You don't need to install shifter specifically.
You just need to follow the steps to install Moodle's grunt tooling: https://docs.moodle.org/dev/Javascript_Modules#Install_grunt. That includes shifter.
You just need to follow the steps to install Moodle's grunt tooling: https://docs.moodle.org/dev/Javascript_Modules#Install_grunt. That includes shifter.