clean code

Author: silentcloud

src/PullToRefresh.tsx

@@ -156,7 +156,6 @@ export default class PullToRefresh extends React.Component<PropsType, any> {
   onTouchMove = (ele: any, e: any) => {
     // 使用 pageY 对比有问题
     const _screenY = e.touches[0].screenY;
-    let direction = '';
     if (this.props.direction === UP_DOWN) {
       // if props.direction = up_down, auto detect direction when ontouchmove
       this._direction = this._startScreenY > _screenY ? UP : DOWN;