both

Returns true if both functions return true for a given set of arguments, false otherwise.

Use the logical and (&&) operator on the result of calling the two functions with the supplied args.

typescript

type Func<T> = (...args: T[]) => any;
export const both =
  <T = any>(f: Func<T>, g: Func<T>) =>
  (...args: T[]) =>
    f(...args) && g(...args);

typescript

const isEven = (num: number) => num % 2 === 0;
const isPositive = (num: number) => num > 0;
const isPositiveEven = both(isEven, isPositive);
isPositiveEven(4); // true
isPositiveEven(-2); // false