code: function getSource(fn, altSource) {
      var result = altSource;
      if (isStringable(fn)) {
        result = String(fn);
      } else if (support.decompilation) {
        // escape the `{` for Firefox 1
        result = (/^[^{]+\{([\s\S]*)}\s*$/.exec(fn) || 0)[1];
      }
      return (result || '').replace(/^\s+|\s+$/g, '');
    }
docs: Gets the source code of a function.
  
  @private
  @param {Function} fn The function.
  @param {String} altSource A string used when a function's source code is unretrievable.
  @returns {String} The function's source code.