batch helper

[Raynos]

levelup has a nice batch api which basically means run the set of puts and removes in a single IDB transaction.

It would allow you to basically run multiple things in one transaction

[Raynos]

    function idbBatch(arr, onSuccess, onError) {
      onError || (onError = function (error) {
        console.error('Could not apply batch.', error);
      });
      onSuccess = onSuccess || noop;
      var batchTransaction = this.db.transaction([this.storeName] , this.consts.READ_WRITE);
      var count = arr.length;
      var called = false;

      arr.forEach(function (operation) {
        var type = operation.type;
        var key = operation.key;
        var value = operation.value;

        if (type == "remove") {
          var deleteRequest = batchTransaction.objectStore(this.storeName).delete(key);
          deleteRequest.onsuccess = function (event) {
            count--;
            if (count == 0 && !called) {
              called = true;
              onSuccess();
            }
          };
          deleteRequest.onerror = function (err) {
            batchTransaction.abort();
            if (!called) {
              called = true;
              onError(err);
            }
          };
        } else if (type == "put") {
          if (typeof value[this.keyPath] == 'undefined' && !this.features.hasAutoIncrement) {
            value[this.keyPath] = this._getUID()
          }
          var putRequest = batchTransaction.objectStore(this.storeName).put(value)
          putRequest.onsuccess = function (event) {
            count--;
            if (count == 0 && !called) {
              called = true;
              onSuccess();
            }
          };
          putRequest.onerror = function (err) {
            batchTransaction.abort();
            if (!called) {
              called = true;
              onError(err);
            }
          };
        }
      }, this);
    }

[jensarps]

Ah, that's a nice idea – batch ops are currently not very convenient to do. Thanks!

[carlos-reynosa]

Great Idea!