TypeScript + Curry

curry-typescript.ts

type ThemeColor = string;
type Theme = { id: number, color: ThemeColor }
type State = { themes?: [Theme] }

interface CurriedFunction1<T1, R> {
    (t1: T1): R;
}

interface CurriedFunction2<T1, T2, R> {
    (t1: T1): CurriedFunction1<T2, R>;
    (t1: T1, t2: T2): R;
}

type Curry<T> =
    T extends () => any ? never[] :
    T extends (t1: infer T1) => infer R ? CurriedFunction1<T1, R> :
    T extends (t1: infer T1, t2: infer T2) => infer R ? CurriedFunction2<T1, T2, R> : any

const selectors = {
    getTheme(state: State, color: ThemeColor): Theme {
        return { id: 1, color: 'red' };
    }
}

type Selectors = {
    [P in keyof typeof selectors]: Curry<typeof selectors[P]>;
}

const example = (selectors: Selectors) => {
    const theme = selectors.getTheme({})("red");
}