compose2.ts

function compose2<T, U>(g: (n: T) => U, f: (m: T) => T) {
    return function (x: T) {
        return g(f(x));
    }
}

const inc = (x: number) =>
    x + 1;

const add = (x: number) => (y: number) =>
    x + y;

const toStr = (x: number) =>
    `${x}`;

const comp = compose2(
    inc,
    add(40),
)

const res = comp(1);

console.log(res);