From 4ac775212f0b3adb376caa15e3072d22779d70ab Mon Sep 17 00:00:00 2001
From: afc163 <afc163@gmail.com>
Date: Sat, 9 Jul 2016 16:00:05 +0800
Subject: [PATCH] Improve code for #2247

---
 components/affix/demo/on-change.md |  7 +----
 components/affix/index.jsx         | 49 ++++++++++++++++++------------
 package.json                       |  1 +
 3 files changed, 31 insertions(+), 26 deletions(-)

diff --git a/components/affix/demo/on-change.md b/components/affix/demo/on-change.md
index 7d8762f5df..674ebb4b9f 100644
--- a/components/affix/demo/on-change.md
+++ b/components/affix/demo/on-change.md
@@ -8,13 +8,8 @@ title: 固定状态改变的回调
 ````jsx
 import { Affix, Button } from 'antd';
 
-
-const onChange = function (affixed) {
-  console.log(affixed); // true or false
-};
-
 ReactDOM.render(
-  <Affix offsetTop={120} onChange={onChange}>
+  <Affix offsetTop={120} onChange={affixed => console.log(affixed)}>
     <Button>固定在距离顶部 120px 的位置</Button>
   </Affix>
 , mountNode);
diff --git a/components/affix/index.jsx b/components/affix/index.jsx
index f371775493..35e03616e4 100644
--- a/components/affix/index.jsx
+++ b/components/affix/index.jsx
@@ -3,6 +3,7 @@ import ReactDOM from 'react-dom';
 import addEventListener from 'rc-util/lib/Dom/addEventListener';
 import classNames from 'classnames';
 import warning from 'warning';
+import shallowequal from 'shallowequal';
 
 function getScroll(w, top) {
   let ret = w[`page${top ? 'Y' : 'X'}Offset`];
@@ -50,6 +51,20 @@ export default class Affix extends React.Component {
     };
   }
 
+  setAffixStyle(affixStyle) {
+    const originalAffixStyle = this.state.affixStyle;
+    if (shallowequal(affixStyle, originalAffixStyle)) {
+      return;
+    }
+    this.setState({ affixStyle }, () => {
+      const affixed = !!this.state.affixStyle;
+      if ((affixStyle && !originalAffixStyle) ||
+          (!affixStyle && originalAffixStyle)) {
+        this.props.onChange(affixed);
+      }
+    });
+  }
+
   handleScroll = () => {
     let { offsetTop, offsetBottom, offset } = this.props;
 
@@ -73,29 +88,23 @@ export default class Affix extends React.Component {
 
     if (scrollTop > elemOffset.top - offsetTop && offsetMode.top) {
       // Fixed Top
-      this.setState({
-        affixStyle: {
-          position: 'fixed',
-          top: offsetTop,
-          left: elemOffset.left,
-          width: ReactDOM.findDOMNode(this).offsetWidth,
-        },
-      }, () => { if (!this.state.affixStyle) this.props.onChange(!!this.state.affixStyle) });
+      this.setAffixStyle({
+        position: 'fixed',
+        top: offsetTop,
+        left: elemOffset.left,
+        width: ReactDOM.findDOMNode(this).offsetWidth,
+      });
     } else if (scrollTop < elemOffset.top + elemSize.height + offsetBottom - window.innerHeight &&
                offsetMode.bottom) {
       // Fixed Bottom
-      this.setState({
-        affixStyle: {
-          position: 'fixed',
-          bottom: offsetBottom,
-          left: elemOffset.left,
-          width: ReactDOM.findDOMNode(this).offsetWidth,
-        },
-      }, () => { if (!this.state.affixStyle) this.props.onChange(!!this.state.affixStyle) });
-    } else if (this.state.affixStyle) {
-      this.setState({
-        affixStyle: null,
-      }, () => this.props.onChange(!!this.state.affixStyle));
+      this.setAffixStyle({
+        position: 'fixed',
+        bottom: offsetBottom,
+        left: elemOffset.left,
+        width: ReactDOM.findDOMNode(this).offsetWidth,
+      });
+    } else {
+      this.setAffixStyle(null);
     }
   }
 
diff --git a/package.json b/package.json
index 1969433026..65f9e71213 100644
--- a/package.json
+++ b/package.json
@@ -70,6 +70,7 @@
     "rc-util": "~3.1.0",
     "react-addons-pure-render-mixin": "^15.0.0",
     "react-slick": "~0.12.0",
+    "shallowequal": "^0.2.2",
     "warning": "~3.0.0"
   },
   "devDependencies": {