phonepad randos

gistfile1.js

const phonepad = [
  [],
  [],
  ['a', 'b', 'c'],
  ['d', 'e', 'f'],
  ['g', 'h', 'i'],
  ['j', 'k', 'l'],
  ['m', 'n', 'o'],
  ['p', 'q', 'r', 's'],
  ['t', 'u', 'v'],
  ['w', 'x', 'y', 'z'],
]

const combine = function(a, min) {
  const fn = function(n, src, got, all) {
    if (n == 0) {
      if (got.length > 0) {
        all[all.length] = got;
      }
      return;
    }
    for (var j = 0; j < src.length; j++) {
      fn(n - 1, src.slice(j + 1), got.concat([src[j]]), all);
    }
    return;
  }
  let all = [];
  for (i = min; i < a.length; i++) {
    fn(i, a, [], all);
  }
  all.push(a);
  return all;
}

const examplePhone = [6, 0, 2, 7, 6, 9, 3, 6, 8, 9];

function getCombos(str) {
  let result = [];
  str.forEach((x) => {
    const phonepadArray = phonepad[x];
    return phonepadArray.reduce((acc, cv, ci, ar) => {
      const res = combine(ar, 2);
      return result.push(res);
    }, 0)
  })
  return result;
}

console.log('subsets', getCombos(examplePhone));