use Partial in nested property with typescript

You can pretty easily define your own RecursivePartial type, which will make all properties, included nested ones, optional:

type RecursivePartial<T> = {
    [P in keyof T]?: RecursivePartial<T[P]>;
};

If you only want some of your properties to be partial, then you can use this with an intersection and Pick:

type PartialExcept<T, K extends keyof T> = RecursivePartial<T> & Pick<T, K>;

That would make everything optional except for the keys specified in the K parameter.

This is possible, you can create a 'deep' partial type as followed:

type DeepPartial<T> = {
    [P in keyof T]?: DeepPartial<T[P]>;
};

Which can be used as followed

const state: DeepPartial<State> = {
    two: {
        three: {
            four: '4'
        }
    }
}