recursion.js

/*
    what will be the o/p of this code ?
    this was asked by one tech lead from fk.
*/
var testObj = {
  bankId: 13,
  accounts: [
    { accountName: "abc", currentBalance: { cash: 10 }, subAccounts: [] },
    {
      accountName: "bcd",
      currentBalance: { cash: 20 },
      subAccounts: [
        {
          accountName: "efg",
          currentBalance: { cash: 30 },
          subAccounts: [
            {
              accountName: "kge",
              currentBalance: { cash: 40 },
              subAccounts: [
                {
                  accountName: "fsd",
                  currentBalance: { cash: 50 },
                  subAccounts: [],
                },
              ],
            },
          ],
        },
        {
          accountName: "der",
          currentBalance: { cash: 70 },
          subAccounts: [
            {
              accountName: "fuh",
              currentBalance: { cash: 80 },
              subAccounts: [],
            },
          ],
        },
      ],
    },
  ],
};

function findAvgSum(obj) {
  const { accounts } = obj || {};
  let sum = 0,
    count = 0,
    i,
    item;

  const runRecursion = (arr) => {
    i = 0;
    while (i < arr.length) {
      item = arr[i] || {};
      const { accountName, currentBalance, subAccounts = [] } = item;
      console.log("accountName", accountName);
      const { cash = 0 } = currentBalance || {};
      sum += cash;
      count++;
      runRecursion(subAccounts);
      i++;
    }
  };

  runRecursion(accounts);

  return sum / count;
}

console.log(findAvgSum(testObj));