# Got stuck on codewars js challenge

I got stuck in codewars challenge that is called `+1 Array` .
The challenge says:

I have 2 failed test cases which is `big arrays` and I tried too much to solve the problem.

Here is my code:

``````function upArray(arr) {
// ...
if (arr.length === 0) return null;
for (let i = 0; i < arr.length; i++) {
if (arr[i] > 9 || arr[i] < 0) return null;
}

arr = arr.join("");
let newArr;
newArr = parseFloat(arr) + 1;
newArr = newArr
.toString()
.split("")
.map(function (i) {
return parseFloat(i);
});
return newArr;
}

``````

The link to the challenge: https://www.codewars.com/kata/5514e5b77e6b2f38e0000ca9/train/javascript

I will suspect that parseFloat is your problem here. The big arrays are intended to test precision, and your number failed the precision test.

Look at the last result:
`[9, NaN, 2,2,3,3,7,2,0,3,6,8,5,4,7,7,6,NaN,NaN,3,6]`

Bet you that when you converted that big number to a string, it gave you `"9.223372036854776e+36"`.

The largest number that can be stored as a Number is 9007199254740991. (2^53 - 1)

``````   9007199254740991
9223372036854775807
``````

(Notice how you lost 3 digits of precision in your answer, getting 000 at the end?)

You’re now in the world of BigInt. (Warning: Make sure your browser is compatible - no IE for you!)

Though I suspect the challenge is trying to make you manipulate the array, rather than doing number conversions? Just a thought.

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