function max(x, fc, fm) // x: lists // fc: compare function (a, b) // fm: map function (v, k, x)

const xlists = require('extra-lists'); var x = [['a', 'b', 'c', 'd'], [1, 2, -3, -4]]; xlists.max(x); // → 2 xlists.max(x, (a, b) => Math.abs(a) - Math.abs(b)); // → -4 xlists.max(x, null, v => Math.abs(v)); // → -4