Function countEntities

countEntities<T extends BaseEntity>(
world: StrataWorld<T>,
...components: (keyof T)[],
): number
Counts entities matching a specific query.

O(1) counting via Miniplex archetype size property when available. Much faster than manually iterating and counting.
Type Parameters
- T extends BaseEntity
Parameters
- world: StrataWorld<T>
  The Strata world.
- ...components: (keyof T)[]
  Component keys to query.
Returns number
Number of matching entities.
Example
```
// Count all enemies
const enemyCount = countEntities(world, 'enemy');
console.log(`${enemyCount} enemies remaining`);
```
Example
```
// Count entities with multiple components
const movableCount = countEntities(world, 'position', 'velocity');

// vs slower manual counting:
// let count = 0;
// for (const _ of world.query('position', 'velocity')) count++;
```
- Defined in src/core/ecs/world.ts:472