/*
  - Reduce
  --- method executes a reducer function on each element of the array,
  --- resulting in a single output value.

  Syntax
  reduce(callBackFunc(Accumulator, Current Val, Current Index, Source Array) { }, initialValue)
  - Accumulator => the accumulated value previously returned in the last invocation
  - Current Val => The current element being processed in the array
  - Index => The index of the current element being processed in the array.
  ---------- Starts from index 0 if an initialValue is provided.
  ---------- Otherwise, it starts from index 1.
  - Array => The Current Array
*/

let nums = [10, 20, 15, 30];

let add = nums.reduce(function (acc, current, index, arr) {
  console.log(`Acc => ${acc}`);
  console.log(`Current Element => ${current}`);
  console.log(`Current Element Index => ${index}`);
  console.log(`Array => ${arr}`);
  console.log(acc + current);
  console.log(`#############`);
  return acc + current;
}, 5);

console.log(add);