Counting The numbers of character in a sentence

I am trying to write a function that counts the number of punctuation in a sentence . but the function is not working.
here is the Instruction:
You should count the number of punctuations now.

Create a getPunctuationCount function with a sentence parameter.

Inside the function, create a loop to count the number of punctuation characters in the sentence that will be passed into the function when it is called. For our purposes, a punctuation character is any character that is not a space (" ") or a letter.

Your getPunctuationCount function must return a number.

here is my code:

function getPunctuationCount(sentence){
  let count = 0
  let space = " "
  let letter = "bcdfghjklmnpqrstvwxyzaeiou"
    for(const punctuation of sentence){
     if(punctuation !== letter  && punctuation !== space){
       count++;
     }
    }
    return count;
}
getPunctuationCount("What's going on here?")
getPunctuationCount("What????!")

What about capital letters?

is a single character going to be equal to 26 letters all at once?

definitely no.
i have lured includes() method into the code .
and it is now working in the right way.
thanks for being there always!
:heart: