['foo' + ++i]: i ◯Is "++i" calculated later? (than "i" , after colon, is set)

Question

The following code is from
JS Tutorial>ES6>ES6 Objects>Computed Property Names>ex2

--
var i = 0;
var a = {
['foo' + ++i]: i,
['foo' + ++i]: i,
['foo' + ++i]: i
};

console.log(a.foo1); // 1
console.log(a.foo2); // 2
console.log(a.foo3); // 3
--

(※the output is
0
1
2)

◯Why the output is different from
the expected one (in its comment)?

◯Is "++i" always calculated
after the value "i" (the one
located after colon) is set?

◯Otherwise, is there another reason?
https://code.sololearn.com/WYujXs5Yk995/?ref=app

Answer 1

I tested the code in Code Playground and it outputs exactly as the comment e.g. 1, 2 and 3 in console. Not sure why you got 0, 1 and 2 instead. Let's see what others has to say later.