07 - Simple Symbols.js

// Step By Step
function SimpleSymbols (str) {
    // First, we declare a variable to hold a regex expression to match all upper and lowercase letters
    var alphaTest = /[a-zA-Z]/;
  
    // Next, we loop through each character in the string...
    for (var i = 0; i < str.length; i++) {
      // ... and use the our previously declared regex expression and the .test method to see if the character is a letter
      if (alphaTest.test(str[i])) {
        // If our test returns true, we check if either of the adjacent characters are not +'s
        if ((str[i + 1] !== '+') || (str[i - 1] !== '+')) {
          // If one of them isn't, we return false.
          return false;
        }
      }
    }
  
    // If our program is able to check all of the characters and hasn't returned false, we know the string obeys all of the problem's rules and can return true.
    return true;
  }
  
  // Without Comments
  function SimpleSymbols (str) {
    for (var i = 0, x = str.length; i < x; i++) {
      if (/[a-zA-Z]/.test(str[i])) {
        if ((str[i + 1] !== '+') || (str[i - 1] !== '+')) {
          return false;
        }
      }
    }
  
    return true;
  }