Function to generate a set of unique alphanumeric codes with a prefixed timestamp

simpleCodeGenerator.js

/**
 * Generate a set of unique alphanumeric codes with a timestamped prefix
 * prefix is parsed as an octal value
 * remainder of the code is in the pattern A99, first character is a letter followed by two numbers
 * every three characters are separated by a hyphen
 * @param  {int} num_codes       the number of codes to generate
 * @param  {int} code_length     the length of codes, does not include hyphens
 * @return {array}               list of codes
 */
function simpleCodeGenerator(num_codes,code_length) {
   if(num_codes > 500) num_codes = 500;
   if(code_length < 4) code_length = 4;
   if(code_length > 16) code_length = 16;
   if(num_codes > Math.pow(10,code_length)) return [];
   
   var codes = [];
   var code = "";

   var digits = "0123456789";
   var chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";

   var d = new Date();
   var prefix = Number(String(d.getFullYear().toString().substr(2, 4)) + String(d.getMonth() + 1) + String(d.getDate())).toString(16);
   var prefix_len = prefix.length;

   // if random
   for (var x = 0; x < num_codes; x++) {
      do {
         code = prefix;
         for (var i = 0; i < code_length-prefix_len; i++) {
            if (i % 3 === 0) code += "-";
            
            if (i % 3 === 0 && (code_length-prefix_len) > i+2) {
               code += chars.charAt(Math.floor(Math.random() * chars.length));
            } else {
               code += digits.charAt(Math.floor(Math.random() * digits.length));
            }
         }
      } while (codes.indexOf(code) >= 0);
      codes.push(code);
   }
   
   return codes;
}
// console.log(simpleHexCodes(100,5));

// var test = (3245).toString(2).match(/1/g).length;
// var test = ("a,b,c,d,e,f,g").split(", ").length;

console.log(simpleCodeGenerator(8,8));

// console.log((3245).toString(2));