对象作为键值会自动转化为字符串

题目

const a = {};
const b = {key:'b'};
const c = {key:'c'};
a[b] = 123;
a[c] = 456

console.log(a[b]); 

答案是456，因为对象作为键值会自动转化为字符串，a[b]相当于a['Object Object']，a[c]也相当于a['Object Object']