chal

challenge1.js

const inputA = 'AAAAAAAAAAAAABBCCCCDD'

function runLength(string) {
  let result = '';
  let count = 1;
  let current = string[0];
  for (let i = 1; i < string.length; i++) {
    if (string[i] === current && count < 9) {
      count++;
    } else {
      result += `${count}${current}`;
      count = 1;
      current = string[i];
    }
  }
  result += `${count}${current}`;
  return result;
}

const outputA = '9A4A2B4C2D'

console.log(JSON.stringify(runLength(inputA)) === JSON.stringify(outputA))

challenge2.js

let inputB = [1, 2, 3, 5, 6, 8, 9]

function squareSort(array) {
  return array.map(num => num * num).sort((a, b) => a - b);
}

const outputB = [1, 4, 9, 25, 36, 64, 81]

console.log(JSON.stringify(squareSort(inputB)) === JSON.stringify(outputB))