@notesnook/localforage-getitems/lib/getitems-indexeddb.js

Adds getItems method to localForage.

import IDBKeyRange from "./idbKeyRange";

export function getItemsIndexedDB(keys /*, callback*/) {
  //keys = keys.slice();
  var localforageInstance = this;
  /* function comparer(a, b) {
    return a < b ? -1 : a > b ? 1 : 0;
  } */

  var promise = new Promise(function(resolve, reject) {
    localforageInstance
      .ready()
      .then(function() {
        // Thanks https://hacks.mozilla.org/2014/06/breaking-the-borders-of-indexeddb/
        var dbInfo = localforageInstance._dbInfo;
        var store = dbInfo.db
          .transaction(dbInfo.storeName, "readonly")
          .objectStore(dbInfo.storeName);

        //var set = keys.sort(comparer);

        var keyRangeValue = IDBKeyRange.bound(
          keys[0],
          keys[keys.length - 1],
          false,
          false
        );
        var req = store.openCursor(keyRangeValue);
        var result = [];
        var i = 0;

        req.onsuccess = function(/*event*/) {
          var cursor = req.result; // event.target.result;

          if (!cursor) {
            resolve(result);
            return;
          }

          var key = cursor.key;

          while (key > keys[i]) {
            // The cursor has passed beyond this key. Check next.
            i++;

            if (i === keys.length) {
              // There is no next. Stop searching.
              resolve(result);
              return;
            }
          }

          if (key === keys[i]) {
            // The current cursor value should be included and we should continue
            // a single step in case next item has the same key or possibly our
            // next key in set.
            var value = cursor.value;
            if (value === undefined) {
              value = null;
            }

            result.push([key, value]);
            // onfound(cursor.value);
            cursor.continue();
          } else {
            // cursor.key not yet at set[i]. Forward cursor to the next key to hunt for.
            cursor.continue(keys[i]);
          }
        };

        req.onerror = function(/*event*/) {
          reject(req.error);
        };
      })
      .catch(reject);
  });
  return promise;
}