Chinese restaurant name generator

restaurant_name.js

/**
 * Randomly generates and returns the the name
 * of a Chinese restaurant, with the given length
 * of words
 * 
 * @param {number} len desired name length
 * in words (2 or 3 supported)
 * @returns {string|null} the generated name, or
 * null if the given name length is invalid
 */
function generateName (len) {
  
  if (len < 2 || len > 3) {
    return null;
  }
  
  let phrases = {
    head: ["China", "Sichuan", "Yunnan", "Hot", "Golden", "Red", "Spicy", "Old", "Eastern"],
    tail: ["Dragon", "Wok", "Lantern", "Taste", "Spice", "Flavor", "Dynasty", "Emperor", "Lotus", "Panda"]
  };

  let n = [];
  
  n.push(phrases.head[Math.floor(Math.random(phrases.head.length))]);
  n.push(phrases.tail[Math.floor(Math.random(phrases.tail.length))]);
  
  if (len === 3) {
    n.unshift(phrases.head[Math.floor(Math.random(phrases.head.length))]);
  }
  
  return n.join(" ");
}