challenge 341: repeating numbers

challenge-341-repeating-numbers.js

/* https://www.reddit.com/r/dailyprogrammer/comments/7eh6k8/20171121_challenge_341_easy_repeating_numbers/ */
const input = '124489903108444899'
const numbers = {}

for(let digits = 2; digits < input.length; digits++) {
  for(let index = 0; index < input.length - digits + 1; index++) {
    let chunk = input.substr(index, digits)

    chunk in numbers ?
    numbers[chunk]++ :
    numbers[chunk] = 1
  }
}

Object.entries(numbers)
.filter(numberPair => numberPair[1] > 1)
.map(numberPair => numberPair.join(':'))
.join(' ') || 0