The current implementation is very odd: (1) you don't need to check whether numbers are odd if your equation works (2) your equation is unnecessarily convoluted.

The current implementation is very odd: (1) you don't need to check whether numbers are odd if your equation works (2) your equation is unnecessarily convoluted.

Refactored it, have a look.

Why use Math.round if you can use Math.floor/Math.ceil? I also failed to consider edge cases properly: 0 is pronic but 1 is not. The following should work:

if (number === 0) return true
const sqrt = Math.sqrt(number)
return sqrt % 1 !== 0 && Math.ceil(sqrt) * Math.floor(sqrt) === number

Please extend the tests to check all example numbers listed on https://oeis.org/A002378 - it's easy to mess up some edge cases. Also check that all other numbers in the range aren't false positives.

Why use Math.round if you can use Math.floor/Math.ceil? I also failed to consider edge cases properly: 0 is pronic but 1 is not. The following should work:

if (number === 0) return true
const sqrt = Math.sqrt(number)
return sqrt % 1 !== 0 && Math.ceil(sqrt) * Math.floor(sqrt) === number

Please extend the tests to check all example numbers listed on https://oeis.org/A002378 - it's easy to mess up some edge cases. Also check that all other numbers in the range aren't false positives.

Added, have a look.