test.js

test.js

//exercise 1

function toLeet(input) {
  let leet = {
      a: "4",
      A: "4",
      e: "3",
      E: "3",
      i: "1",
      I: "1",
      o: "0",
      O: "0",
      s: "5",
      S: "5",
      t: "7",
      T: "7",
      b: "5",
      D: "5" // Not sure if this was a typo and meant B
    };
    return input.replace(/[aAeEoOsStTbBD]/gi, m => leet[m]);
}

//exercise 2

function frequencyList(input) {
  return input.replace(/(.)\1*/g, function(strs, i) {
    //returns the character + the number of times matched
    return i + strs.length;
  });
}

// test cases
console.assert(toLeet('Let's have some fun.') == 'L37\'5 h4v3 50m3 fun.');
// .. more for toLeet

console.assert(frequencyList('aaabbdcccccf') == 'a3b2d1c5f1');