fix there was no trigger event for the first time

Author: jljsj33

examples/link.js

@@ -29,7 +29,11 @@ class Demo extends React.Component {
     console.log(e, 'blur');
   }
 
-  barAnimate() {
+  onChange = (e) => {
+    console.log(e);
+  }
+
+  barAnimate = () => {
     if (!this.dom) {
       return;
     }
@@ -71,7 +75,7 @@ class Demo extends React.Component {
           <div ref="bar" className="nav-bar" />
         </div>
       </div>
-      <Element className="pack-page page0" id="page0">
+      <Element className="pack-page page0" id="page0" onChange={this.onChange}>
         <QueueAnim className="home-title">
           <div className="page-title" key="title">
             <p>{_package.name}@{_package.version}</p>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "rc-scroll-anim",
-  "version": "0.5.0",
+  "version": "0.5.1",
   "description": "scroll-anim anim component for react",
   "keywords": [
     "react",

src/ScrollElement.jsx

@@ -7,11 +7,6 @@ import { currentScrollTop, transformArguments, windowHeight, toArrayChildren } f
 const noop = () => {
 };
 class ScrollElement extends React.Component {
-  constructor(props) {
-    super(props);
-    this.enter = false;
-  }
-
   componentDidMount() {
     this.dom = ReactDOM.findDOMNode(this);
     if (this.props.id) {
@@ -49,7 +44,7 @@ class ScrollElement extends React.Component {
     const enter = this.elementShowHeight >= this.playHeight
       && this.elementShowHeight <= this.clientHeight + this.leavePlayHeight;
     const enterOrLeave = enter ? 'enter' : 'leave';
-    const mode = this.enter !== enter ? enterOrLeave : null;
+    const mode = this.enter !== enter || typeof this.enter !== 'boolean' ? enterOrLeave : null;
     if (mode) {
       this.props.onChange({ mode, id: this.props.id }, e);
     }