| <!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title></title>
</head>
<body>
</body>
<script type="text/javascript">
//isEqual：判断两个对象是否键值对应相等
function isEqual(a,b){
//如果a和b本来就全等
if(a===b){
//判断是否为0和-0
return a !== 0 || 1/a ===1/b;
}
//判断是否为null和undefined
if(a==null||b==null){
return a===b;
}
//接下来判断a和b的数据类型
var classNameA=toString.call(a),
classNameB=toString.call(b);
//如果数据类型不相等，则返回false
if(classNameA !== classNameB){
return false;
}
//如果数据类型相等，再根据不同数据类型分别判断
switch(classNameA){
case '[object RegExp]':
case '[object String]':
//进行字符串转换比较
return '' + a ==='' + b;
case '[object Number]':
//进行数字转换比较,判断是否为NaN
if(+a !== +a){
return +b !== +b;
}
//判断是否为0或-0
return +a === 0?1/ +a === 1/b : +a === +b;
case '[object Date]':
case '[object Boolean]':
return +a === +b;
}
//如果是对象类型
if(classNameA == '[object Object]'){
//获取a和b的属性长度
var propsA = Object.getOwnPropertyNames(a),
propsB = Object.getOwnPropertyNames(b);
if(propsA.length != propsB.length){
return false;
}
for(var i=0;i<propsA.length;i++){
var propName=propsA[i];
//如果对应属性对应值不相等，则返回false
if(a[propName] !== b[propName]){
return false;
}
}
return true;
}
//如果是数组类型
if(classNameA == '[object Array]'){
if(a.toString() == b.toString()){
return true;
}
return false;
}
}
//test
var obj1={name:"liu",age:22};
var obj2={name:"liu",age:22};
var obj3={name:"liu",age:33};
var state1=isEqual(obj1,obj2);
var state2=isEqual(obj1,obj3);
console.log(state1);//true
console.log(state2);//false
var state3=isEqual(null,undefined);
console.log(state3);//false
var state4=isEqual(NaN,NaN);
console.log(state4);//true
var arr1=[1,2,3];
var arr2=[1,2,3];
var arr3=[1,23];
var state5=isEqual(arr1,arr2);
console.log(state5);//true
var state6=isEqual(arr1,arr3);
console.log(state6);//false
</script>
</html>
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