Explain the shortest JS function creation using a key of an object [closed]

Question

var o = {["k"](){}}; // {k: ƒ}
o.k();

Here you can see an example:

How {["k"](){}} is compiled to an object which has a key k inside which is a function?

Answer 1

{["k"](){}}

equals:

{
  k(){}
}

Which is ES2015 short method syntax for:

{
  k: function(){}
}