export async function handleNavigation()

in packages/fxa-settings/src/pages/Signin/utils.ts [158:228]
56 lines of code
15 McCabe index (conditional complexity)

export async function handleNavigation(navigationOptions: NavigationOptions) {
  const { integration } = navigationOptions;
  const isOAuth = isOAuthIntegration(integration);
  const isWebChannelIntegration =
    integration.isSync() || integration.isDesktopRelay();

  if (!navigationOptions.signinData.verified) {
    const { to, locationState } =
      getUnverifiedNavigationTarget(navigationOptions);
    if (
      isWebChannelIntegration &&
      navigationOptions.handleFxaLogin === true &&
      // If the _next page_ is `signin_totp_code`, we don't want to send this
      // because we end up sending it twice with the first message containing
      // `verified: false`, causing a Sync sign-in issue (see FXA-9837).
      !to?.includes('signin_totp_code')
    ) {
      sendFxaLogin(navigationOptions);
    }
    performNavigation({ to, locationState });
    return { error: undefined };
  }

  if (
    navigationOptions.signinData.verificationReason ===
    VerificationReasons.CHANGE_PASSWORD
  ) {
    // TODO in FXA-6653: remove hardNavigate when this route is converted to React
    hardNavigate('/post_verify/password/force_password_change', {}, true);
    return { error: undefined };
  }

  if (isWebChannelIntegration && navigationOptions.handleFxaLogin === true) {
    // This _must_ be sent before fxaOAuthLogin for Desktop OAuth flow.
    // Mobile doesn't care about this message (see FXA-10388)
    sendFxaLogin(navigationOptions);
  }

  if (!isOAuth) {
    const { to, locationState, shouldHardNavigate } =
      await getNonOAuthNavigationTarget(navigationOptions);
    performNavigation({ to, locationState, shouldHardNavigate });
    return { error: undefined };
  }

  // Note that OAuth redirect can only be obtained when the session is verified,
  // otherwise oauth/authorization endpoint throws an "unconfirmed session" error
  if (isOAuth) {
    const { to, locationState, oauthData, shouldHardNavigate, error } =
      await getOAuthNavigationTarget(navigationOptions);

    if (error) {
      return { error };
    }
    if (
      isOAuthNativeIntegration(integration) &&
      navigationOptions.handleFxaOAuthLogin === true &&
      oauthData
    ) {
      firefox.fxaOAuthLogin({
        action: 'signin',
        code: oauthData.code,
        redirect: oauthData.redirect,
        state: oauthData.state,
      });
    }
    performNavigation({ to, locationState, shouldHardNavigate });
  }

  return { error: undefined };
}