JAVASCRIPT

fabric download

here is the install for the client
https://fabricmc.net/use/installer/
about half of the mods using fabric also use fabric api so you may as well check that out too
https://www.curseforge.com/minecraft/mc-mods/fabric-api

Installing fabric

$ pip3 uninstall Fabric
$ sudo apt-get install libffi-dev
$ sudo apt-get install libssl-dev
$ sudo apt-get install build-essential
$ sudo apt-get install python3.4-dev
$ sudo apt-get install libpython3-dev
$ pip3 install pyparsing
$ pip3 install appdirs
$ pip3 install setuptools==40.1.0
$ pip3 install cryptography==2.8
$ pip3 install bcrypt==3.1.7
$ pip3 install PyNaCl==1.3.0
$ pip3 install Fabric3==1.14.post1

Installing fabric

$ pip3 uninstall Fabric
$ sudo apt-get install libffi-dev
$ sudo apt-get install libssl-dev
$ sudo apt-get install build-essential
$ sudo apt-get install python3.4-dev
$ sudo apt-get install libpython3-dev
$ pip3 install pyparsing
$ pip3 install appdirs
$ pip3 install setuptools==40.1.0
$ pip3 install cryptography==2.8
$ pip3 install bcrypt==3.1.7
$ pip3 install PyNaCl==1.3.0
$ pip3 install Fabric3==1.14.post1