Function _refreshRemoteConfig

ts/RemoteConfig.dom.ts:182–342

({
  getConfig,
  storage,
}: OptionsType)

}

export const _refreshRemoteConfig = async ({
  getConfig,
  storage,
}: OptionsType): Promise<void> => {
  const now = Date.now();
  const oldConfigHash = storage.get('remoteConfigHash');

  const {
    config: newConfig,
    serverTimestamp,
    configHash,
  } = await getConfig(oldConfigHash);

  const serverTimeSkew = serverTimestamp - now;

  if (Math.abs(serverTimeSkew) > HOUR) {
    log.warn(
      'Remote Config: severe clock skew detected. ' +
        `Server time ${serverTimestamp}, local time ${now}`
    );
  }

  if (newConfig === 'unmodified') {
    log.info(
      'remote config was unmodified; server-generated hash is %s',
      configHash
    );
    return;
  }

  // Process new configuration in light of the old configuration. Since the
  // new configuration only includes enabled flags we can't distinguish betewen
  // a remote flag being deleted or being disabled. We synthesize that for our
  // known keys.
  const newConfigValues = new Map<string, string | undefined>(
    KnownConfigKeys.map(name => [name, undefined])
  );
  for (const [name, value] of newConfig) {
    newConfigValues.set(name, value);
  }

  const changedKeys = new Set<string>();
  const changeDescriptions: Array<{
    name: string;
    from: string;
    to: string;
  }> = [];

  const oldConfig = config;
  let semverError = false;
  config = Array.from(newConfigValues.entries()).reduce(
    (acc, [name, value]) => {
      const enabled = value !== undefined && value.toLowerCase() !== 'false';
      const previouslyEnabled: boolean = get(
        oldConfig,
        [name, 'enabled'],
        false
      );