export async function onAddEmail()

in src/app/(proper_react)/(redesign)/(authenticated)/user/(dashboard)/settings/actions.ts [50:146]
87 lines of code
12 McCabe index (conditional complexity)

export async function onAddEmail(
  _prevState: AddEmailFormState,
  formData: FormData,
): Promise<AddEmailFormState> {
  // If `_reset` is set returning `success: false` resets the `useActionState`
  // we are calling this server action from.
  if (formData.get("_reset")) {
    return {
      success: false,
    };
  }

  const l10n = getL10n(await getAcceptLangHeaderInServerComponents());
  const session = await getServerSession();
  if (!session?.user.subscriber?.fxa_uid) {
    return {
      success: false,
      error: "add-email-without-active-session",
      errorMessage: l10n.getString("user-add-invalid-email"),
    };
  }
  const subscriber = (await getSubscriberByFxaUid(
    session.user.subscriber?.fxa_uid,
  )) as SubscriberRow | null;
  if (!subscriber) {
    return {
      success: false,
      error: "no-subscriber-data-found",
      errorMessage: l10n.getString("user-add-invalid-email"),
    };
  }
  const submittedAddress = formData.get("newEmailAddress");
  const validatedEmailAddress =
    typeof submittedAddress === "string"
      ? validateEmailAddress(submittedAddress)
      : null;

  if (validatedEmailAddress === null) {
    return {
      success: false,
      error: "invalid-email",
      errorMessage: l10n.getString("user-add-invalid-email"),
    };
  }

  const maxNumEmailAddresses = hasPremium(subscriber)
    ? CONST_MAX_NUM_ADDRESSES_PLUS
    : CONST_MAX_NUM_ADDRESSES;
  const existingAddresses = [session.user.email]
    .concat(subscriber.email_addresses.map((emailRow) => emailRow.email))
    .map((address) => address.toLowerCase());
  if (existingAddresses.length >= maxNumEmailAddresses) {
    return {
      success: false,
      error: "too-many-emails",
      errorMessage: l10n.getString("user-add-too-many-emails"),
    };
  }

  if (existingAddresses.includes(validatedEmailAddress.email.toLowerCase())) {
    return {
      success: false,
      error: "address-already-added",
      errorMessage: l10n.getString("user-add-duplicate-email"),
    };
  }

  try {
    const unverifiedSubscriber = await addSubscriberUnverifiedEmailHash(
      subscriber,
      validatedEmailAddress.email,
    );

    await initEmail();
    await sendVerificationEmail(subscriber, unverifiedSubscriber.id);
    revalidatePath("/user/settings");

    return {
      success: true,
      submittedAddress: validatedEmailAddress.email,
    };
  } catch (e) {
    if (e instanceof Error && e.message === "error-email-validation-pending") {
      return {
        success: false,
        error: "verification-email-just-sent",
        errorMessage: l10n.getString("user-add-verification-email-just-sent"),
      };
    }

    return {
      success: false,
      error: "unknown-error",
      errorMessage: l10n.getString("user-add-unknown-error"),
    };
  }
}