code: function $number(params) {
      if (params == null) {
          return params;
      }
      if (typeof params === 'number') {
          return params;
      }
      if (typeof params === 'string') {
          return Number(params);
      }
      throw new Error('$number expects a number or string');
  }
docs: Parse the given string into a number
  
  @param {string} params
  @returns {number}