setState typescript signature is too restrictive.

The typescript signature of setState is too restrictive, since it assumes it’s parameter must be exactly the type of the component’s StateType type parameter.

TypeScript has a builtin type Partial<T> that has the same type as T, but with all properties forced to be optional defined as:

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

And define the signature of setState to be setState(state: Partial<StateType>, opts?: any).

I’ll PR this in when I have a moment!

[Avol-V]

Also have the same problem.

If I describe my State as strong set of options:

interface MyState
{
	option1: string;
	option2: string[];
}

I can’t set only one option in set:

this.setState(
	{option1: 'Hello'}, // Error: Property 'option2' is missing
);

But if I mark options with ?:

interface MyState
{
	option1?: string;
	option2?: string[];
}

I have another problem – TypeScript think that options can be undefined (but I set them in constructor):

const option2 = [...this.state.option2, 'new']; // Error

So wating for

setState(state: Partial<StateType>, opts?: any): void;

[ericanderson]

After TS 2.1.5 comes out, we should be able to merge the react changes.