As far as I know, the "correct" approach is to act as if every object is deeply frozen (perhaps actively testing using Object.freeze... IMO https://github.com/ecomfe/babel-plugin-freeze-const has the right idea but is nothing more than an idea), and transform things into new objects functionally, using .map and friends.

The problem is that, while a lot of things can be expressed elegantly this way, sometimes the most maintainable thing, or the most efficient thing, is to have some side effects in a deep loop in a certain algorithm, and it's very difficult to do this with purely functional JS.

The real solution is to allow your const bindings to be mutated when you need to, and comment explicitly to make things perfectly clear!