wallet-core/packages/demobank-ui/src/hooks/settings.ts

/*
 This file is part of GNU Taler
 (C) 2022 Taler Systems S.A.

 GNU Taler is free software; you can redistribute it and/or modify it under the
 terms of the GNU General Public License as published by the Free Software
 Foundation; either version 3, or (at your option) any later version.

 GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
 A PARTICULAR PURPOSE.  See the GNU General Public License for more details.

 You should have received a copy of the GNU General Public License along with
 GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
 */

import { useLocalStorage } from "@gnu-taler/web-util/browser";

interface Settings {
  currentWithdrawalOperationId: string | undefined;
}

const defaultSettings: Settings = {
  currentWithdrawalOperationId: undefined,
};

function parse_json_or_undefined<T>(str: string | undefined): T | undefined {
  if (str === undefined) return undefined;
  try {
    return JSON.parse(str);
  } catch {
    return undefined;
  }
}

export function useSettings(): [
  Readonly<Settings>,
  <T extends keyof Settings>(key: T, value: Settings[T]) => void,
] {
  const { value, update } = useLocalStorage("demobank-settings");

  const parsed: Settings = parse_json_or_undefined(value) ?? defaultSettings;
  function updateField<T extends keyof Settings>(k: T, v: Settings[T]) {
    const newValue = { ...parsed, [k]: v };
    const json = JSON.stringify(newValue);
    update(json);
  }
  return [parsed, updateField];
}