Function unionSets

packages/db/src/utils/index-optimization.ts:95–103

(sets: Array<Set<T>>)

 * Unions multiple sets (OR logic)
 */
export function unionSets<T>(sets: Array<Set<T>>): Set<T> {
  const result = new Set<T>()
  for (const set of sets) {
    for (const item of set) {
      result.add(item)
    }
  }
  return result
}

/**
 * Whether a value can be matched exactly by an index lookup, i.e. the index