title: Find the missing letter in an array
body: <p>I am trying to create a function that takes an array input of consecutive characters in the alphabet and returns the missing letter if there is one (there will only be 1 missing letter and each element in the array will be listed in alphabetical order).</p>
  
  <p>Example inputs:</p>
  
  <pre><code>['a', 'b', 'c', 'e'] -&gt; 'd'
  ['l', 'n', 'o', 'p'] -&gt; 'm'
  ['s', 't', 'u', 'w', 'x'] -&gt; 'v'
  
  const findMissingLetter = () =&gt; {
  const stepOne = (array) =&gt; {
      for (let i = 0; i &lt; array.length; i++) {
          let x = array.charCodeAt(i + 1);
          let y = array.charCodeAt(i);
              if ((x - y) != 1) {
                  return (array.charCodeAt[i] + 1);
              }
    }
  }
  }
  return findMissingLetter(stepOne.fromCharCode(array));
  </code></pre>
  
  <p>What I am attempting to do is loop through each index of the array and convert each character to unicode. If the  [i + 1] - [i] elements in the array equal 1, then there is no missing letters. However if it does not equal 1, then I want to return the unicode of [i] + 1 and then through the higher order function convert the unicode output back to the corresponding character in the alphabet.</p>
  
  <p>Can someone please explain what I am doing wrong? I know I am not calling the functions correctly.</p>
  
  <p>Thanks!</p>