Merge pull request #101 from liuxy0551/fix_100

fix: #100 await IndexedDB open

Author: jin-sir

docs/idb.md

@@ -29,7 +29,7 @@ const request = LocalIndexedDB.open(数据库名, 数据库版本);
 request.onsuccess = function(event) {
   // Do something with request.result!
 };
-request.onupgradeneeded = function(evevt) {
+request.onupgradeneeded = function(event) {
  // 当创建新数据库或增加现有数据库的版本号
 }
 request.onblocked = function(event) {

src/indexedDB.ts

@@ -56,13 +56,16 @@ class LocalIndexedDB {
                     console.log('Open indexedDB success!');
                 };
 
+                // onupgradeneeded -> transaction.oncomplete -> onsuccess
                 request.onupgradeneeded = function (e: any) {
                     console.log('openDb.onupgradeneeded', e);
                     self._db = request.result;
                     if (!self._db.objectStoreNames.contains(self._storeName)) {
-                        self._db.createObjectStore(self._storeName);
+                        const objectStore = self._db.createObjectStore(self._storeName);
+                        objectStore.transaction.oncomplete = function () {
+                            resolve(request.result);
+                        };
                     }
-                    resolve(request.result);
                 };
 
                 request.onblocked = function (e: any) {