【Factory】惰性单例

patterns-factory-lazy-singleton.js

var LazySingleton = (function() {
  // 单例实例引用
  var instance = null;
  // 单例
  function Singleton() {
    return {
      publicMethod: function() {},
      publicProperty: '1'
    }
  }
  return function () {
    if (!instance) {
      instance = Singleton();
    }
    return instance;
  }
})();

console.log(LazySingleton().publicProperty); // '1'