[backend] fix: 修复异常处理和类型转换问题

frontend/node_modules/toggle-selection/README.md

@@ -0,0 +1,18 @@
+# Toggle Selection
+
+Simple module exposing function that deselects current browser selection and returns function that restores selection.
+
+```
+var deselect = require('toggle-selection');
+var reselect = deselect(); // remove all selection
+// … 
+// do something with current selection, text, etc;
+// …
+reselect(); // restore selection
+```
+
+All credits go to [@shvaikalesh](https://github.com/shvaikalesh).
+
+# [Example](https://github.com/sudodoki/toggle-selection/blob/master/example)
+
+![example recording](http://g.recordit.co/YPu6mHvcKe.gif)