ip address range match

ip-address-range.js

console.log('something');
const _ = require('lodash');
const { assert } = require('chai');

const SAMPLE_RULES_BLOCK = [
    ['103.1.108.1','AU'],
    ['3.254.254.254','US'],
    ['5.10.64.17','CN'],
    ['0.0.0.0-0.12.13.14','FR'],
    ['209.88.2.2-209.88.2.255','AZ'],
];

/*
 * returns a country or 'UNKNOWN'
 *
 * ipAddress will be a IPv4 address in dot notation: 'a.b.c.d'
 * assume all addresses passed are valid.
 */
function lookupCountry(ipAddress) {
  // implement me.... 
  var countryTuple = _.find(SAMPLE_RULES_BLOCK, function(rule) {
    var staticMatch = rule.indexOf(ipAddress) !== -1;
    if (staticMatch) {
      return true;
    }
    if (rule[0].indexOf('-') === -1) {
      return false;
    }
    var rangeMatchArr = rule[0].split('-');
    var rangeMatchMin = rangeMatchArr[0].split('.').map(toNumber);
    var rangeMatchMax = rangeMatchArr[1].split('.').map(toNumber);
    var ipAddressParts = ipAddress.split('.').map(toNumber);
    var inRange = true;
    
    var inRangeSoFar;
    
    return checkPosition(0);
    
    function checkPosition(i) {
      if (i > 3) {
        return false;
      }
      
      var min = rangeMatchMin[i];
      var max = rangeMatchMax[i];
      
      if (inRangeSoFar) {
        min = 0;
        max = 255;
      }
      
      if (ipAddressParts[i] > min && 
          ipAddressParts[i] < max) {
        inRangeSoFar = true;
        return true;
      } else if (ipAddressParts[i] === min ||
                 ipAddressParts[i] === max) {
        if (i === 2) {
          return true;
        }
        return checkPosition(i + 1);
      } else {
        // out of range
        return false;
      }
    }
  });
  if (countryTuple) {
    return countryTuple[1];
  }
  
  return 'UNKNOWN';
  
  function toNumber(i) {
    return parseInt(i);
  }
}

function test_lookupCountry() {
  const cases = {
    '103.1.108.1' : 'AU',
    '3.254.254.254' : 'US',
    '5.10.64.17' : 'CN',
    '127.0.0.1' : 'UNKNOWN',
    '0.12.1.255' : 'FR',
    '209.88.2.123' : 'AZ',
  }

  _.toPairs(cases).forEach(function([ip, country]) {
    assert.equal(lookupCountry(ip), country);
  })
}

test_lookupCountry();