在javascript中-将变量保存为参考

Question

var foo = {prop:1};
var bar = {prop:2};
var obj = {};
obj[foo] = 'value';
console.log(obj[bar]); //'value'

It is quite confusing why obj[bar] and obj[foo] are same now, whereas foo and bar are not same.

Answer 1

because

obj[foo]='value';

is the same as

obj["[object Object]"]='value';

Object keys are string so it's internally doing foo.toString()

and foo.toString() === bar.toString()

Every objects will return "[object Object]" if used as a key (not talking about arrays, numbers, strings..)

---

You'll need something that uniquely identify your objects, like below

var foo = {id:"foo", prop:1};
var bar = {id:"bar", prop:2};
var obj = {};
obj[foo.id] = 'value';
console.log(obj[bar.id]); //undefined