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Introduction and Installation

KubeJS is a mod that lets you modify a lot about Minecraft, in a quick and easy way. As such, it's become the prime tool for Modpack Developers looking to add and edit things together.

Installation

Install the mod and its two dependencies Architectury and Rhino. Make sure that you use the most resent version of each mods for your version.

When you first install KubeJS, you will need to launch Minecraft with the mods to generate the some folders and files.

The KubeJS folder

Finding it

Everything you do in KubeJS in located in the kubejs folder in your instance.

  • In Prism the file structure will look like polymc > instances > (instance name) > minecraft > kubejs
  • In the CurseForge launcher the file structure will look like curseforge > minecraft > instances > (instance name) > kubejs
    • In all of the above cases the (instance name) is the name of the instance
  • In the normal Minecraft launcher it will be .minecraft > kubejs, unless you changed the instance folder, but using the normal launcher for modding is highly discourged, due to the above offering utility.

From now on, this will be referenced as the kubejs folder.

The contents

When you are first getting started, these three folders will be the most important.

  • Scripts that get loaded once during game startup
  • Used for adding items and other things that can only happen while the game is loading
  • Can reload code not in an event with /kubejs reload_startup_scripts
  • To reload all the code you must restart the game
  • Scripts that get loaded every time server resources reload (world load, /reload)
  • Used for modifying:
    • recipes
    • tags
    • loot tables
    • handling server events
  • Can reload code not in an event with /kubejs reload server_scripts
  • Can be all the code in server_scripts with /reload
  • Scripts that get loaded every time client resources reload
  • Used for:
    • JEI events
    • tooltips
    • other client side things
  • Can reload code not in an event with /kubejs reload client_scripts
  • Can reload all the code in client_scripts with F3+T

Useful commands

Typing in /kubejs hand ingame will display your currently held item's name and tags, clicking on one of these will copy it to your clipboard. This can also be shortened to /kjs hand, and you can also use the up arrow to resend a previously send command.

The /kubejs hotbar and /kubejs inventory will print what you are currently holding into chat as an array, which you can click on as well.

Other Useful Tools

Code is just a language that computers can understand. However, the grammar of the language, called syntax for code, is very precise. When you code has a syntactical error, the computer does not know what to do and will probably do something that you do not desire.

With KubeJS we will be writing a lot of code, so it important to avoid these errors. Luckily, there are tools called code editors, that can help us write code correctly.

Installing Visual Studio Code is recommended, as it is light-ish and has great built in JS support. Now when you edit you javascript files, it will not only warn you when you make most syntactical errors, but also help you prevent them in the first place.