Function isBase64ImageBlock

src/utils/imageValidation.ts:40–49

* Type guard to check if a block is a base64 image block

(
  block: unknown,
)

 * Type guard to check if a block is a base64 image block
 */
function isBase64ImageBlock(
  block: unknown,
): block is { type: 'image'; source: { type: 'base64'; data: string } } {
  if (typeof block !== 'object' || block === null) return false
  const b = block as Record<string, unknown>
  if (b.type !== 'image') return false
  if (typeof b.source !== 'object' || b.source === null) return false
  const source = b.source as Record<string, unknown>
  return source.type === 'base64' && typeof source.data === 'string'
}

/**
 * Validates that all images in messages are within the API size limit.