title: Switch statement returning undefined
body: <pre><code>function getLetter(s) {
      let letter = s[0];
      // Write your code here
      let A = ['a','e','i','o','u'];
      let B = ['b','c','d','f','g'];
      let C = ['h','j','k','l','m'];
      let D = ['n','p','q','r','s','t','v','w','x','y','z'];
  
    switch(letter) {
      case A.includes(s.charAt(0)): 
        return 'A';
      break;
  
      case B.includes(s.charAt(0)): 
        return 'B';
      break;
  
      case C.includes(s.charAt(0)): 
        return 'C';
      break;
  
      case D.includes(s.charAt(0)): 
          return 'D';
      break;
    }
  }
  
  s = 'adam';
  t = getLetter(s);
  console.log(t);
  </code></pre>
  
  <p>I'm learning switches and I'm trying this problem where I'm supposed to pass in a string and the function getLetter() is supposed to return 'A' if the first letter of the string is any of the elements in array A. And similar for arrays B,C,D. I tried the code above but it returns undefined. What am I doing wrong?</p>