closure-compiler software package provides JavaScript optimizing compiler, you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install closure-compiler
closure-compiler is installed in your system.
Make ensure the closure-compiler package were installed using the commands given below,
$ sudo dpkg-query -l | grep closure-compiler *
You will get with closure-compiler package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Java |
| Package | closure-compiler |
| Version | 20130227+dfsg1-9 |
| Description | JavaScript optimizing compiler |
| Sub Section | Java |