Function normalizeParams

api/src/utils/redirection.ts:57–85

(
  { returnTo, origin, pathPrefix }: Partial<RedirectParams>,
  _homeLocation = HOME_LOCATION
)

 * @returns The normalized parameters.
 */
export function normalizeParams(
  { returnTo, origin, pathPrefix }: Partial<RedirectParams>,
  _homeLocation = HOME_LOCATION
): RedirectParams {
  // coerce to strings, just in case something weird and nefarious is happening
  // TODO: validate, don't coerce
  returnTo = '' + returnTo;
  origin = '' + origin;
  pathPrefix = '' + pathPrefix;
  // TODO(Post-MVP): consider adding HOME_LOCATION in allowedOrigins to allow
  // redirection to work in development.
  // we add the '/' to prevent returns to
  // www.freecodecamp.org.somewhere.else.com
  if (
    !returnTo ||
    !allowedOrigins.some(allowed => returnTo?.startsWith(allowed + '/'))
  ) {
    returnTo = `${_homeLocation}/learn`;
    origin = _homeLocation;
    pathPrefix = '';
  }
  if (!origin || !allowedOrigins.includes(origin)) {
    returnTo = `${_homeLocation}/learn`;
    origin = _homeLocation;
    pathPrefix = '';
  }
  pathPrefix = availableLangs.client.includes(pathPrefix) ? pathPrefix : '';
  return { returnTo, origin, pathPrefix };
}

/**
 * Get the prefixed landing path.