That will break with

> Uncaught TypeError: Cannot convert undefined or null to object

because `myObjectArr.at` doesn't bind `this` to `myObjectArr`. When the internals of `map` call the `at` function, `this` is just `undefined` instead of the original array and it'll throw.

Luckily Array.prototype.map takes a second argument just for this purpose

    indices.map(myObjectArr.at, myObjectArr)