Function findLastCompactBoundaryIndex

src/utils/messages.ts:4718–4729

(messages: T[])

 * @returns The index of the last compact boundary, or -1 if none found
 */
export function findLastCompactBoundaryIndex<
  T extends Message | NormalizedMessage,
>(messages: T[]): number {
  // Scan backwards to find the most recent compact boundary
  for (let i = messages.length - 1; i >= 0; i--) {
    const message = messages[i]
    if (message && isCompactBoundaryMessage(message)) {
      return i
    }
  }
  return -1 // No boundary found
}

/**
 * Returns messages from the last compact boundary onward (including the boundary).