Calculate a “Net Promoter Score” from an array of integers.
$ npm install --save gist:34e4f906939ee1bafc74b82e64d4cc48
const nps = require('@flesch/net-promoter-score');
const score = nps([10, 9, 10, 8, 7, 5, 6, 9, 10]);
console.log(score); // => 33
0(n)