code: function encodeWrap(nodeText) {
          if (!nodeText) {
              return '';
          }
          var textArr = [],
              WRAP_TEXT = ['\\', 'n'];
          for (var i = 0, j = 0, l = nodeText.length; i < l; i++) {
              if (nodeText[i] === '\n' || nodeText[i] === '\r') {
                  textArr.push('\\n');
                  j = 0;
                  continue;
              }
              if (nodeText[i] === WRAP_TEXT[j]) {
                  j++;
                  if (j === 2) {
                      j = 0;
                      textArr.push('\\\\n');
                  }
                  continue;
              }
              switch (j) {
                  case 0: {
                      textArr.push(nodeText[i]);
                      break;
                  }
                  case 1: {
                      textArr.push(nodeText[i-1], nodeText[i]);
                  }
              }
              j = 0;
          }
          return textArr.join('');
      }
docs: 对节点text中的换行符进行处理
  @method encodeWrap
  @param  {String}   nodeText MinderNode.data.text
  @return {String}            \n -> '\n'; \\n -> '\\n'