JS Challenge: Check if a string is a palindrome

Any string, after removing whitespaces and punctuations, that reads the same when the order of letters is reversed - regardless of the case of letters - is considered a palindrome. For example:

'Was it a car or a cat I saw?'

So the steps involved are:

1. Convert the string to uniform case
2. Remove all non-alphabet characters from the string
3. Reverse the order of letters and check if it reads the same as the original string

const str = "Was it a car or a cat I saw?";
[...str.toLowerCase().replace(/[^a-z]/g, '')].join('') ===
 [...str.toLowerCase().replace(/[^a-z]/g, '')].reverse().join('')