var a = { };
var b = {
key: "a"
};
var c = {
key: "c"
};
a[b] = "123"
a[c] = "456"
console.log(a[b]);
输出的结果是 456
因为
对象的键值会转换为字符串 a[b] == a["[object Object]"]
可以打印一下看看结果
console.log(b.toString() == "[object Object]");
和这个结果
console.log(a["[object Object]"]);
原文：https://www.cnblogs.com/chenyi4/p/11533117.html