Question

下面是一个比较两个JavaScript对象的示例，但我对返回的值感到困惑。

var i=new Object()
var j=new Object()

i==j false

i!=j true

i>=j true

i<=j true

i>j false

i<j false

如何确定上述值？我无法理解。

Answer 1

原因如下，

i==j false //Since both are referring two different objects

i!=j True  //Since both are referring two different objects

i>=j true  //For this, the both objects will be converted to primitive first,
           //so i.ToPrimitive() >= j.ToPrimitive() which will be 
           //evaluated to "[object Object]" >= "[object Object]" 
           //That is why result here is true.

i<=j true  //Similar to >= case

i>j false  //Similar to >= case

i<j false  //Similar to >= case

i<-j false //similar to >= case but before comparing "[object object]" will be negated 
           //and will become NaN. Comparing anything with NaN will be false 
           //as per the abstract equality comparison algorithm

您提到i<-j将被评估为true。但这是错误的，它将被评估为false。看看上面的原因。

Answer 2

因为每次创建对象并将其分配给变量时，该变量才真正具有对新对象的引用。引用不一样，所以它们不相等。你可以这样做：

var a = {};
var b = a;

a == b

不是很有启发性，但如果你认为参考，那一切都是有道理的。

两个javascript对象如何在同一时间相等且不相等？

2 个答案: