Function combineHeadersForUrl

js/bundle/src/encoder.ts:301–320

(
  headers: Headers,
  overrideHeadersOption: OverrideHeadersOption,
  url: string
)

// Based on the type of the overrideHeadersOption combines the original headers
// with the override headers.
export function combineHeadersForUrl(
  headers: Headers,
  overrideHeadersOption: OverrideHeadersOption,
  url: string
) {
  if (!overrideHeadersOption) return headers;

  const headersForUrl =
    typeof overrideHeadersOption == 'function'
      ? overrideHeadersOption(url)
      : overrideHeadersOption;

  if (!isHeaders(headersForUrl)) {
    throw new Error(
      'Malformatted override headers: They should be an object of strings.'
    );
  }

  return { ...headers, ...headersForUrl };
}