解释下面代码的输出

Question

var a={},    b={key:'b'},    c={key:'c'};a[b]=123;a[c]=456;console.log(a[b]);这段代码为什么输出的是 456 ？

Answer 1

a[b] = 123会转化为a["[object Object]"] = 123
a[c] = 456会转化为a["[object Object]"] = 456
console.log(a[b])会转化为console.log(a["[object Object]"])

因此是结果为456