parseInt("number length greater than 15")

Question

I was solving a problem in leet code, Solution I came up with made all test cases passed except for one. Input of that test case is an array = [6,1,4,5,3,9,0,1,9,5,1,8,6,7,0,5,5,4,3]. so I have convert the array into a number add 1 to entire number and then convert it back to array format with result, in my solution one step before final statement, I have used parseInt("6145390195186705543")+1 then I convert to string and split and then convert to number. but during parseInt(), this in-built method is not able to convert after 15th digits, im getting output as [6145390195186705000], sending 0's after 15 digits, so does anyone has any idea on how to convert a string of number length more than 16 to Number P.S: I have tried bigInt() method, techincally it would work but for the problem bigInt() is not working and output isnt working

var plusOne = function(digits) {
  let y = digits.map(String);
  let z = ''
  for (let i = 0; i < y.length; i++) {
    z += y[i];
  }
  let a = (parseInt(z) + 1).toString().split('')
  return a.map(Number)
};

Answer 1

Loop backwards over the digits, and

• if the digit is less than 9, add 1 and stop
• otherwise the digit is 9, so set it to 0 and if the 9 was the first digit in the array, insert a 1 at the beginning of the array

function addOne(digitArray) {
  for (let i = digitArray.length - 1; i >= 0; i--) {
    if (digitArray[i] < 9) {
      digitArray[i] += 1
      break
    } else {
      digitArray[i] = 0
      if (i === 0) {
        digitArray.unshift(1)
      }
    }
  }
  return digitArray
}

console.log(addOne([]))         // []
console.log(addOne([ 0 ]))      // [ 1 ]
console.log(addOne([ 9 ]))      // [ 1, 0 ]
console.log(addOne([ 1, 0 ]))   // [ 1, 1 ]
console.log(addOne([ 1, 9 ]))   // [ 2, 0 ]
console.log(addOne([ 9, 9 ]))   // [ 1, 0, 0 ]

console.log(addOne([ 6, 1, 4, 5, 3, 9, 0, 1, 9, 5, 1, 8, 6, 7, 0, 5, 5, 4, 3 ]))
// [ 6, 1, 4, 5, 3, 9, 0, 1, 9, 5, 1, 8, 6, 7, 0, 5, 5, 4, 3 ]