ConsumableChemicals

Chemicals are tracked per player. A mod that wants a new one writes a Chemical Handler, either from scratch by extending ConsumableChemicalHandler or by picking one of the pre-made abstract handlers. The pre-made handlers need only one method implemented. The author text gives HalfLifeChemicalHandler as the example: a chemical whose amount halves every 5 minutes, or 6000 ticks, where tickPlayer handles the per-tick removal until none is left.

Once a handler class is written, it must be registered. The mod adds chemicals to the game itself, so a chemicals command can edit a player's chemical levels, which makes testing possible without playing through the game. Food can carry chemicals as well: a FoodProperties builder has a new method that takes a ResourceLocation for the chemical, the handler itself and an amount, and the player receives the chemical on consuming the item.

Food data for 1.20.5 and later lives in Item Components. Chemicals can be added to items through the ChemicalMap component type, whose ID is chemicals:chemicals, and a simple command gives a steak with 100 units of a chemical as an example. On 1.20.4 and earlier the ChemicalMap.Builder is used for registering a custom item's default chemical amount. The mod is published for Fabric only.