localdata.js

(function() {
  var win = typeof window !== 'undefined' ? window : {}
  var indexedDB = win.indexedDB || win.mozIndexedDB || win.webkitIndexedDB || win.msIndexedDB;
  if (typeof window !== 'undefined' && !indexedDB) {
    console.error('indexDB not supported');
    return;
  }
  var db,
    request = indexedDB.open('ldb', 1);
  request.onsuccess = function(evt) {
    db = this.result;
  };
  request.onerror = function(event) {
    console.error('indexedDB request error');
    console.log(event);
  };

  request.onupgradeneeded = function(event) {
    db = null;
    var store = event.target.result.createObjectStore('s', {
      keyPath: 'k'
    });

    store.transaction.oncomplete = function (e){
      db = e.target.db; 
    };
  };

  // if using proxy mode comment this

  var ldb = {
    ready: false,
    get: function(key, callback) {
      if (!db) {
        setTimeout(function () { ldb.get(key, callback); }, 50);
        return;
      }
      db.transaction('s').objectStore('s').get(key).onsuccess = function(event) {
        var result = (event.target.result && event.target.result['v']) || null;
        callback(result);
      };
    },
    set: function(key, value, callback) {
      if (!db) {
        setTimeout(function () { ldb.set(key, value, callback); }, 50);
        return;
      }
      let txn = db.transaction('s', 'readwrite'); 
      txn.oncomplete = function(event) {
        var toString$ = {}.toString;
        if (toString$.call(callback).slice(8, -1) === 'Function') {
          callback();
        }
      }
      txn.objectStore('s').put({
        'k': key,
        'v': value,
      });
      txn.commit();
    },
    delete: function(key, callback) {
      if (!db) {
        setTimeout(function () { ldb.delete(key, callback); }, 50);
        return;
      }
      db.transaction('s', 'readwrite').objectStore('s').delete(key).onsuccess = function(event) {
        if (callback) callback();
      };
    },
    list: function(callback) {
      if (!db) {
        setTimeout(function () { ldb.list(callback); }, 50);
        return;
      }
      db.transaction('s').objectStore('s').getAllKeys().onsuccess = function(event) {
        var result = (event.target.result) || null;
        callback(result);
      };
    },
    getAll: function(callback) {
      if (!db) {
        setTimeout(function () { ldb.getAll(callback); }, 50);
        return;
      }
      db.transaction('s').objectStore('s').getAll().onsuccess = function(event) {
        var result = (event.target.result) || null;
        callback(result);
      };
    },
    clear: function(callback) {
      if (!db) {
        setTimeout(function () { ldb.clear(callback); }, 50);
        return;
      }
      db.transaction('s', 'readwrite').objectStore('s').clear().onsuccess = function(event) {
        if (callback) callback();
      };
    },
  }
  const exported = {
    'get': ldb.get,
    'set': ldb.set,
    'delete': ldb.delete,
    'list': ldb.list,
    'getAll': ldb.getAll,
    'clear': ldb.clear,
  };
  win['ldb'] = exported
  if (typeof module !== 'undefined') {
    module.exports = exported;
  }

  // Use only for apps that will only work on latest devices only

  // window.ldb = new Proxy({}, {
  //   get: function(func, key, callback) {
  //     return (key === 'get') ? getValue : function(callback) {
  //       return getValue(key, callback)
  //     };
  //   },
  //   set: function(func, key, value) {
  //    let txn = db.transaction('s', 'readwrite'); 
  //    txn.oncomplete = function(event) {
  //      var toString$ = {}.toString;
  //      if (toString$.call(callback).slice(8, -1) === 'Function') {
  //        callback();
  //      }
  //    }
  //    txn.objectStore('s').put({
        //   'k': key,
        //   'v': value,
        // });
  //    txn.commit();
  //   }
  // });
})();