old_contents: /**
   * Created by hustcc on 17/08/01.
   */
  
  /**
   * what( v ) -> String : get what is the type of the input var.
   * @param v: the var which want to typeof
   * @returns {string}
   * https://github.com/hustcc/what.js
   */
  
  function what(v) {
    if (v === null) return 'null';
    if (v === undefined) return 'undefined';
    var t = typeof v;
    // performance opt
    if (
      t === 'string' ||
      t === 'number' ||
      t === 'function' ||
      t === 'boolean'
    ) return t;
    if (v !== Object(v)) return t;
    return ({}).toString.call(v).slice(8, -1).toLowerCase();
  }
  
  module.exports = what;
  
new_contents: /**
   * Created by hustcc on 17/08/01.
   */
  
  /**
   * what( v ) -> String : get what is the type of the input var.
   * @param v: the var which want to typeof
   * @returns {string}
   * https://github.com/hustcc/what.js
   */
  
  function what(v) {
    if (v === null) return 'null';
    if (v === undefined) return 'undefined';
    var t = typeof v;
    // performance opt
    if (
      t === 'string' ||
      t === 'number' ||
      t === 'function' ||
      t === 'boolean'
    ) return t;
    // if (v !== Object(v)) return t;
    return ({}).toString.call(v).slice(8, -1).toLowerCase();
  }
  
  module.exports = what;
  
subject: remove unused code