Creating a Datapack and Recipe

About Datapacks

Datapacks are Minecraft's way to add and remove data and features from the game while it's running. You can find the wiki page here if you want more information, but this page will go over the basics.

1. Create a new folder inside your world save folder, under datapacks. You can name it anything, and it will show up in MC that way. The rest of the steps will use mydata as a placeholder.
2. Under the mydata folder, create a pack.mcmeta file (named exactly that) and insert the text below.
3. Create a data folder under mydata.
4. Create a NAMESPACE folder under data. Replace NAMESPACE with your mod ID or something unique (like cclaustrophia) as this will become the recipe's namespace.
5. Create a recipes folder under mydata.

The file structure should look like this when you're done:

pack.mcmeta

(From Minecraft Wiki)

{
    "pack": {
        "pack_format": 6,
        "description": "The default data for Minecraft"
    }
}

Creating a recipe

Once you have a basic datapack structure, you can now follow the recipe specification to add any recipes you like (not just Compact Crafting recipes, either!). For that, go to the Recipe Specification page. In short, create a new file called myrecipe.json (name it something unique) and place it under recipes in the pack structure above.