js中判断Object、Array、Function等引⽤类型对象是否相等的⽅
法
js中判断Object、Array、Function等引⽤类型对象是否相等，引⽤类型⽆法直接使⽤ == 或=== 取得期待结果。
法⼀：需要⼀个迭代的compare函数转化成原始类型进⾏⽐较
function compare(a,b){
var pt = /undefined|number|string|boolean/, fn = /^(function\s*)(\w*\b)/, cr = "constructor", cn = "childNodes",
pn ="parentNode",
ce = arguments.callee;
st(typeof a) || pt.test(typeof b) || a === null || b === null){
return a === b || (isNaN(a) && isNaN(b)); //为了⽅便，此处假定NaN == NaN
}
if(a[cr] !== b[cr]){
return false;
}
switch(a[cr]){
case Date : {
return a.valueOf() === b.valueOf();
};
case Function : {
String().replace(fn,'$1') === b.toString().replace(fn,'$1'); //硬编码中声明函数的⽅式会影响到toString的结果，因此⽤正则进⾏格式化
};
case Array : {
if(a.length !== b.length){
return false;
}
for(var i=0;i<a.length;i++){
if(!ce(a[i],b[i])){
return false;
}
}
break;
};
default : {
var alen = 0, blen = 0, d;
if(a === b){
return true;
}
if(a[cn] || a[pn] || b[cn] || b[pn]){
return a === b;
}
for(d in a){
alen++ ;
}
for(d in b){
blen++;
}
if(alen !== blen){
return false;
}
for(d in a){
if(!ce(a[d],b[d])){
return false;
}
}
break;
};
}
return true;
}
console.log(compare({},{a:1})); //false
console.log(compare({a:1},{b:2})); //false
console.log(compare({b:2,a:1},{a:1,b:2})); //true
console.log(compare({a:function(){return false;},b:2},{a:function(){return false;},b:2})); //true
console.log(compare([],[])); //true
console.log(compare([2,1],[1,2])); //false
console.log(compare(function(){alert(1)},function(){})); //false
console.log(compare(function aaa(){alert(1)},function(){alert(1)})); //true
console.log(ElementsByTagName("a")[0],ElementsByTagName("a")[1])); //true
console.log(ElementsByTagName("a")[0],ElementsByTagName("a")[0])); //true
法⼆：直接检测Array或Object的⽤arguments.callee
function equal(objA, objB)
{
if (typeof arguments[0] != typeof arguments[1])
return false;
console.log(arguments[0],arguments[1]);
//数组
if (arguments[0] instanceof Array)
{
if (arguments[0].length != arguments[1].length)
return false;
var allElementsEqual = true;
js arguments
for (var i = 0; i < arguments[0].length; ++i)
{
if (typeof arguments[0][i] != typeof arguments[1][i])
return false;
if (typeof arguments[0][i] == 'number' && typeof arguments[1][i] == 'number')
allElementsEqual = (arguments[0][i] == arguments[1][i]);
else
allElementsEqual = arguments.callee(arguments[0][i], arguments[1][i]);            //递归判断对象是否相等        }
return allElementsEqual;
}
//对象
if (arguments[0] instanceof Object && arguments[1] instanceof Object)
{
var result = true;
var attributeLengthA = 0, attributeLengthB = 0;
for (var o in arguments[0])
{
//判断两个对象的同名属性是否相同（数字或字符串）
if (typeof arguments[0][o] == 'number' || typeof arguments[0][o] == 'string')
result = eval("arguments[0]['" + o + "'] == arguments[1]['" + o + "']");
else {
//如果对象的属性也是对象，则递归判断两个对象的同名属性
//if (!arguments.callee(arguments[0][o], arguments[1][o]))
if (!arguments.callee(eval("arguments[0]['" + o + "']"), eval("arguments[1]['" + o + "']")))
{
result = false;
return result;
}
}
++attributeLengthA;
}
for (var o in arguments[1]) {
++attributeLengthB;
}
//如果两个对象的属性数⽬不等，则两个对象也不等
if (attributeLengthA != attributeLengthB)
result = false;
return result;
}
return arguments[0] == arguments[1];
}
var a = {Name:"YuanXP",Id:9,Go:{a:'1',b:'2'}};
var b = {Id:9,Name:"YuanXP",'Go':{a:'1',b:'2'}};
var c= equal(a, b);
console.log(c);

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