argMin and argMax functions for JavaScript

argMinMax.js

const argFact = (compareFn) => (array) => array.map((el, idx) => [el, idx]).reduce(compareFn)[1]

const argMax = argFact((min, el) => (el[0] > min[0] ? el : min))
const argMin = argFact((max, el) => (el[0] < max[0] ? el : max))

argMin([42, -5, 3.14, 1e6]) // 1
argMax([42, -5, 3.14, 1e6]) // 3