Function normalizeHeaders

deps/undici/src/lib/mock/snapshot-utils.js:104–135

* Normalizes headers for consistent comparison * * @param {Object|UndiciHeaders} headers - Headers to normalize * @returns {NormalizedHeaders} - Normalized headers as a lowercase object

(headers)

 * @returns {NormalizedHeaders} - Normalized headers as a lowercase object
 */
function normalizeHeaders (headers) {
  /** @type {NormalizedHeaders} */
  const normalizedHeaders = {}

  if (!headers) return normalizedHeaders

  // Handle array format (undici internal format: [name, value, name, value, ...])
  if (isUndiciHeaders(headers)) {
    for (let i = 0; i < headers.length; i += 2) {
      const key = headers[i]
      const value = headers[i + 1]
      if (key && value !== undefined) {
        // Convert Buffers to strings if needed
        const keyStr = Buffer.isBuffer(key) ? key.toString() : key
        const valueStr = Buffer.isBuffer(value) ? value.toString() : value
        normalizedHeaders[keyStr.toLowerCase()] = valueStr
      }
    }
    return normalizedHeaders
  }

  // Handle object format
  if (headers && typeof headers === 'object') {
    for (const [key, value] of Object.entries(headers)) {
      if (key && typeof key === 'string') {
        normalizedHeaders[key.toLowerCase()] = Array.isArray(value) ? value.join(', ') : String(value)
      }
    }
  }

  return normalizedHeaders
}

const validSnapshotModes = /** @type {const} */ (['record', 'playback', 'update'])