freeCodeCamp Challenge Guide: Use Recursion to Create a Range of Numbers

camperbot · August 3, 2019, 5:46am

Use Recursion to Create a Range of Numbers

Solutions

Solution 1 (Click to Show/Hide)

function rangeOfNumbers(startNum, endNum) {
  if (endNum < startNum) {
    return [];
  } else {
    const numbers = rangeOfNumbers(startNum, endNum - 1);
    numbers.push(endNum);
    return numbers;
  }
}

Solution 2 (Click to Show/Hide)

function rangeOfNumbers(startNum, endNum) {
  return endNum < startNum
    ? []
    : rangeOfNumbers(startNum, endNum - 1).concat(endNum);
}

Solution 3 (Click to Show/Hide)

function rangeOfNumbers(startNum, endNum) {
  return endNum < startNum
    ? []
    : [...rangeOfNumbers(startNum, endNum - 1), endNum];
}