code: function getSource(fn) {
        var result = '';
        if (isStringable(fn)) {
          result = String(fn);
        } else if (support.decompilation) {
          // Escape the `{` for Firefox 1.
          result = _.result(/^[^{]+\{([\s\S]*)\}\s*$/.exec(fn), 1);
        }
        // Trim string.
        result = (result || '').replace(/^\s+|\s+$/g, '');
  
        // Detect strings containing only the "use strict" directive.
        return /^(?:\/\*+[\w\W]*?\*\/|\/\/.*?[\n\r\u2028\u2029]|\s)*(["'])use strict\1;?$/.test(result)
          ? ''
          : result;
      }
docs: Gets the source code of a function.
  
  @private
  @param {Function} fn The function.
  @returns {string} The function's source code.