Function decodeUtf8NoBom

packages/blocks/src/deepnote-file/parse-yaml.ts:20–33

(bytes: Uint8Array)

 * ```
 */
export function decodeUtf8NoBom(bytes: Uint8Array): string {
  // Reject UTF-8 BOM (0xEF 0xBB 0xBF)
  if (bytes.length >= 3 && bytes[0] === 0xef && bytes[1] === 0xbb && bytes[2] === 0xbf) {
    throw new EncodingError('UTF-8 BOM detected in Deepnote file - files must be UTF-8 without BOM')
  }

  // Validate UTF-8 by decoding with fatal=true
  // This will throw if the bytes contain invalid UTF-8 sequences
  try {
    return new TextDecoder('utf-8', { fatal: true }).decode(bytes)
  } catch {
    throw new EncodingError('Invalid UTF-8 encoding detected in Deepnote file')
  }
}

/**
 * Validates that a string doesn't start with BOM.