gpDA

function fill(times, number) {
  if (times <= 0) return [];

  return [number].concat(fill(times -1, number));
}

console.log(fill(5, 2)); // [2, 2, 2, 2, 2]

gpDA

function recLen(str) {
    if (str == '') return 0
    return recLen(str.substring(1)) + 1;
}

let str ="abcd";
console.log(recLen(str));

gpDA

function getElementsByClassName(className) {
    const results = [];

    const checkRecursive = (element, cName) => {
        const cn = element.getAttribute("class");
        if (cn !== undefined && cn !== null && cn.includes(cName)) {
            results.push(element);
        }
				// element.children MDN
        if (element.children.length > 0) {

gpDA

function flatten(arr, ret = []) {
    for (const entry of arr) {
        if (Array.isArray(entry)) {
            flatten(entry, ret)
        } else {
            ret.push(entry)
        }
    }
    return ret;
}

gpDA

const findFibonacci = (n) => {
  if (n == 1) return [0, 1];

  let res = findFibonacci(n-1);
  res.push(res[res.length - 1] + res[res.length - 2])
  return res;
}

console.log(findFibonacci(5)); // [0, 1, 1, 2, 3, 5]

gpDA

// recursion
const recursiveFindRange = (low, high) => {
    if (low === high - 2) return [high - 1];
  
    let res = recursiveFindRange(low, high - 1)
    res.push(high - 1);
    return res;
  
};

gpDA

const recursiveDigitSum = (number) => {
    if (number === 0) return 0;
    return number % 10 + recursiveDigitSum(Math.floor(number / 10))
}

gpDA

const factorialNumber = (num) => {
  if (num === 1) return 1;

  return num * factorialNumber(num - 1);
}

console.log(factorialNumber(5)); // 120

gpDA

function fibonacci(num) {
    if(num < 2) {
        return num;
    }
    else {
        return fibonacci(num-1) + fibonacci(num - 2);
    }
}

gpDA

// recursion 1 - using helper function
const RecursiveHelperProductArr = (arr) => {
    let index = arr.length - 1;

    // helper function
    const recur = (curIndex, acc) => { 
      acc *= arr[curIndex];
      if (curIndex === 0) return acc;
      return recur(curIndex - 1, acc); // decrement the index and recursion
    }