both

Checks if both of the given functions return true for a given set of arguments.

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

const both = (f, g) => (...args) => f(...args) && g(...args);

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