diff --git a/src/matrix/storage/idb/Storage.ts b/src/matrix/storage/idb/Storage.ts
index ad155a17..ceab34f9 100644
--- a/src/matrix/storage/idb/Storage.ts
+++ b/src/matrix/storage/idb/Storage.ts
@@ -21,8 +21,13 @@ import { reqAsPromise } from "./utils";
 const WEBKITEARLYCLOSETXNBUG_BOGUS_KEY = "782rh281re38-boguskey";
 
 export class Storage {
-    constructor(idbDatabase, IDBKeyRange, hasWebkitEarlyCloseTxnBug) {
+    private _db: IDBDatabase
+    private _hasWebkitEarlyCloseTxnBug: boolean
+    storeNames: { [ name : string] : string }
+
+    constructor(idbDatabase: IDBDatabase, IDBKeyRange, hasWebkitEarlyCloseTxnBug: boolean) {
         this._db = idbDatabase;
+        // @ts-ignore
         this._IDBKeyRange = IDBKeyRange;
         this._hasWebkitEarlyCloseTxnBug = hasWebkitEarlyCloseTxnBug;
         const nameMap = STORE_NAMES.reduce((nameMap, name) => {
@@ -32,14 +37,14 @@ export class Storage {
         this.storeNames = Object.freeze(nameMap);
     }
 
-    _validateStoreNames(storeNames) {
+    _validateStoreNames(storeNames: string[]) {
         const idx = storeNames.findIndex(name => !STORE_NAMES.includes(name));
         if (idx !== -1) {
             throw new StorageError(`Tried top, a transaction unknown store ${storeNames[idx]}`);
         }
     }
 
-    async readTxn(storeNames) {
+    async readTxn(storeNames: string[]): Promise<Transaction> {
         this._validateStoreNames(storeNames);
         try {
             const txn = this._db.transaction(storeNames, "readonly");
@@ -48,13 +53,14 @@ export class Storage {
             if (this._hasWebkitEarlyCloseTxnBug) {
                 await reqAsPromise(txn.objectStore(storeNames[0]).get(WEBKITEARLYCLOSETXNBUG_BOGUS_KEY));
             }
+            // @ts-ignore
             return new Transaction(txn, storeNames, this._IDBKeyRange);
         } catch(err) {
             throw new StorageError("readTxn failed", err);
         }
     }
 
-    async readWriteTxn(storeNames) {
+    async readWriteTxn(storeNames: string[]): Promise<Transaction> {
         this._validateStoreNames(storeNames);
         try {
             const txn = this._db.transaction(storeNames, "readwrite");
@@ -63,6 +69,7 @@ export class Storage {
             if (this._hasWebkitEarlyCloseTxnBug) {
                 await reqAsPromise(txn.objectStore(storeNames[0]).get(WEBKITEARLYCLOSETXNBUG_BOGUS_KEY));
             }
+            // @ts-ignore
             return new Transaction(txn, storeNames, this._IDBKeyRange);
         } catch(err) {
             throw new StorageError("readWriteTxn failed", err);