error-detector code style tweak

Author: yyx990803

src/compiler/error-detector.js

@@ -2,17 +2,22 @@
 
 import { dirRE, onRE } from './parser/index'
 
-// operators like typeof, instanceof and in are allowed
+// these keywords should not appear inside expressions, but operators like
+// typeof, instanceof and in are allowed
 const prohibitedKeywordRE = new RegExp('\\b' + (
   'do,if,for,let,new,try,var,case,else,with,await,break,catch,class,const,' +
   'super,throw,while,yield,delete,export,import,return,switch,default,' +
   'extends,finally,continue,debugger,function,arguments'
 ).split(',').join('\\b|\\b') + '\\b')
+
+// these unary operators should not be used as property/method names
 const unaryOperatorsRE = new RegExp('\\b' + (
   'delete,typeof,void'
 ).split(',').join('\\s*\\([^\\)]*\\)|\\b') + '\\s*\\([^\\)]*\\)')
+
 // check valid identifier for v-for
 const identRE = /[A-Za-z_$][\w$]*/
+
 // strip strings in expressions
 const stripStringRE = /'(?:[^'\\]|\\.)*'|"(?:[^"\\]|\\.)*"|`(?:[^`\\]|\\.)*\$\{|\}(?:[^`\\]|\\.)*`|`(?:[^`\\]|\\.)*`/g