### Pipe functions Use `Array.reduce()` with the spread operator (`...`) to perform left-to-right function composition. The first (leftmost) function can accept one or more arguments; the remaining functions must be unary. ```js const pipe = (...fns) => fns.reduce((f, g) => (...args) => g(f(...args))); /* const add5 = x => x + 5 const multiply = (x, y) => x * y const multiplyAndAdd5 = pipe(multiply, add5) multiplyAndAdd5(5, 2) -> 15 */ ```