fix(ts): validate d.ts beforerunning test

fixed #497

Author: leeyeh

package.json

@@ -8,7 +8,9 @@
     "url": "https://github.com/leancloud/javascript-sdk"
   },
   "scripts": {
-    "test": "NODE_ENV=test nyc --reporter lcov --reporter text mocha --timeout 300000 test/index.js",
+    "lint": "tsc storage.d.ts",
+    "test": "npm run lint && npm run test:node",
+    "test:node": "NODE_ENV=test nyc --reporter lcov --reporter text mocha --timeout 300000 test/index.js",
     "docs": "jsdoc src README.md package.json -d docs -c .jsdocrc.json",
     "build:node": "gulp babel-node",
     "build:browser": "CLIENT_PLATFORM=Browser webpack --config webpack/browser.js",
@@ -51,6 +53,7 @@
     "nyc": "^8.1.0",
     "qiniu": "^6.1.11",
     "should": "^11.1.0",
+    "typescript": "^2.4.1",
     "weapp-polyfill": "^1.1.0",
     "webpack": "^2.2.0-rc.3"
   },

storage.d.ts

@@ -1,3 +1,7 @@
+interface IteratorResult<T> {
+  done: boolean;
+  value: T;
+}
 interface AsyncIterator<T> {
   next(): Promise<IteratorResult<T>>
 }
@@ -553,7 +557,6 @@ declare namespace AV {
         signUp(attrs?: any, options?: AuthOptions): Promise<User>;
         logIn(options?: AuthOptions): Promise<User>;
         linkWithWeapp(): Promise<User>;
-        fetch(options?: AuthOptions): Promise<User>;
         isAuthenticated(): Promise<boolean>;
         isCurrent(): boolean;