Coding Problems - Alphabetical center

alphabetical.js

/**
 * Simple Text: Write a method in which provided two strings, it returns a string between them.  Additionally, a 
 * percentage will be provided to allow us to fine-tune the outcome.
 * 
 * Nerd Text: Given two strings A & B where 'a' <= A <= B <= 'z' and a skew N where 0 <= N <= 1.  Write a method that 
 * returns a value X where A <= X <= B relative to N. The intent of the skew is to dictate where X should fall between 
 * A & B.  Meaning X will not always be exactly halfway between.
 * 
 * Caveats:  
 *  - The examples below treat N as a linear value so your results might be different.  This is acceptable as long as 
 * the general concept is followed.
 *  - Shorter the string the better, we are not looking for a true midpoint of two strings.
 */

// Examples:
alphabetical('a', 'a'){ … };        // return 'a'
alphabetical('a', 'e', 0.5){ … };   // return 'c'
alphabetical('a', 'e', 0.8){ … };   // return 'd'
alphabetical('aaa', 'ccc'){ … };    // return 'b'
alphabetical('aa', 'ac'){ … };      // return 'ab'
alphabetical('aaa', 'aac'){ … };    // return 'aab'
alphabetical('aa', 'ab'){ … };      // return 'aam'
alphabetical('aabb', 'aacc'){ … };  // return 'aac'