JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash-fp/0.10.4/lodash-fp.min.js"></script>

JavaScript

function sum(...input) {
	return _.flow(
  				_.flattenDeep,
    			_.reduce((n, i) => n + i, 0)
  				)(input);
}
var x = [1, [2, 3, [4], [[[5]]], 6, [[7, 8]]], 9];

console.log(sum(x)); // 45