Сходящиеся функции ветвления

const converge = (converger, fns) => (…args) =>
  converger(…fns.map(fn => fn.apply(null, args)));

const average = converge((a, b) => a / b, [
  arr => arr.reduce((a, v) => a + v, 0),
  arr => arr.length
]);
average([1, 2, 3, 4, 5, 6, 7]); // 4