find-unused-id.js

const data = require('./coriolis-data/dist/index.json')

function combinations(arr, k) {
  let i
  let subI
  const ret = []
  let sub
  let next
  for (i = 0; i < arr.length; i++) {
    if (k === 1) {
      ret.push([arr[i]])
    } else {
      sub = combinations(arr.slice(i + 1, arr.length), k - 1)
      for (subI = 0; subI < sub.length; subI++) {
        next = sub[subI]
        next.unshift(arr[i])
        ret.push(next)
      }
    }
  }
  return ret
}

const alphabet = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'T', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z']
const possibleIds = combinations(alphabet, 2)
console.log(`Possible IDs: ${possibleIds.length}`)
const list = []

function getId(arr) {
  if (typeof arr === 'object') {
    for (const i in arr) {
      if (typeof arr[i] === 'object' && !arr[i].id) {
        getId(arr[i])
      } else if (arr[i].id) {
        list.push(arr[i].id)
      }
    }
  }
}

getId(data)
possibleIds.forEach((elem, ind) => possibleIds[ind] = elem.join(''))
for (const i of possibleIds) {
  if (list.indexOf(i) === -1) {
    console.log(`Unused ID: ${i}`)
    break
  }
}