MxtElements: Elements and Accumulation

Elements and accumulation are two different things: list/has read the spirit roots (what the body is), while amount/attach read and write a per-element accumulation table (how much it has built up). The four methods share one object, but they read two different states.

Methods

Method	Parameters	Return value	Description
list(entity)	Entity	List<String>	The element IDs the entity's currently active spirit roots name, sorted. Switched-off roots contribute nothing; an entity with no roots answers an empty list.
has(entity, element)	Entity, element ID	boolean	Whether the entity's spirit roots name that element.
amount(entity, element)	Entity, element ID	double	How much of that element has built up on the entity; 0 when none has, and 0 for an unknown element. A client reads its synchronised copy.
attach(entity, element, amount)	Entity, element ID, finite number	double	Builds that element up on the entity (a negative amount wears it off) through the same pipeline a strike uses, and returns the new total. A qualifying element_reaction fires as usual.

attach is equivalent to the entity action mxt:attach_element, so a lava bath, a pill or a curse written from a script behaves the same way, and a negative amount cleanses. The three readers work on either side — the accumulation is a synchronised attachment, so a client script reads its local copy, which is exactly what an item tooltip does — and only attach is a server operation: on a client, or with an unknown element, a non-finite value or 0, it returns 0 and changes nothing.

// kubejs/server_scripts/mxt_element.js
PlayerEvents.tick(event => {
  const player = event.player
  if (player.level().isClientSide()) return
  // "has a water root and has built up 8 fire" — visible before any reaction fires.
  if (MxtElements.has(player, 'mxt_test:water') && MxtElements.amount(player, 'mxt_test:fire') >= 8) {
    console.info(`water cultivator carrying ${MxtElements.list(player)}`)
  }
})

// Let a custom event build fire up on a target; the element_reaction in the data pack settles it.
MxtElements.attach(target, 'mxt_test:fire', 4)

Related

• Data pack side: element and element_reaction.
• Where elements come from: MxtSpiritRoots (the element a root binds) and MxtAura (the aura around it).
• The element factors on the damage pipeline: Damage.
• KubeJS API Reference.