Latched triggers

resolveLatchedTriggers evaluates authored one-shot triggers in array order. The product supplies its own condition and effect schemas, state persistence, and presentation events.

Resolution sequence

For each trigger:

1. skip it when isLatched(state, id) is true;
2. evaluate conditionMet against the current state;
3. persist the latch before effects run;
4. apply every effect in authored array order; and
5. append the id to the returned fired list.

Latching first prevents an effect that causes nested or later trigger evaluation from firing the same trigger again.

const fired = resolveLatchedTriggers(world, level.triggers, {
  isLatched: (state, id) => state.firedTriggerIds.has(id),
  conditionMet: (state, condition) => evaluateCondition(state, condition),
  latch: (state, id) => state.firedTriggerIds.add(id),
  applyEffect: (state, effect, trigger) => applyEffect(state, effect, trigger.id),
});

Authored-order semantics

Later trigger conditions observe state changes from earlier triggers in the same pass. This makes authored order part of the rules, not merely presentation. If triggers must qualify simultaneously, snapshot their condition results in the product before calling the helper or model them as separate settlement jobs.

Effects within one trigger also run sequentially. Keep the effect array stable across serialization and avoid object-key enumeration as implicit author order.

Persistence and identities

The helper stores no internal latch set. latch must update the same state observed by isLatched, and that state must survive save/load and replay when the trigger is meant to be permanently one-shot. Trigger ids should be unique within that persistence scope.

Product responsibilities

Conditions, effects, trigger reset policy, scopes, spawning, dialogue, rewards, and visual events remain product-owned. When effects cause more same-tick work, enqueue it through tick settlement instead of recursively calling the entire trigger pass.

Zonoid example

Zonoid levels can author one-shot board events such as “switch pressed,” “plug powered,” “agent reached this cell,” “evidence collected,” or “tick reached.” The platform evaluates those conditions and applies feature-cell rewrites such as opening a wall or unlocking an exit; the SDK latches the event before its effects, so replay and nested settlement cannot fire it twice.

Focused Zonoid demo board: the player steps on, off, and back onto a switch to show that its one-shot trigger fires only once.