diff --git a/src/js/parser/javascript/grammar.peg b/src/js/parser/javascript/grammar.peg
index 073fc7b..d7fe88b 100644
--- a/src/js/parser/javascript/grammar.peg
+++ b/src/js/parser/javascript/grammar.peg
@@ -24,18 +24,18 @@ grammar JavascriptRegexp
                           / charset_literal <Literal>
   charset_escape <- "\\" esc:(
          code:[bdDfnrsStvwW] arg:""?
-       / code:"c" arg:[a-zA-Z]
-       / code:"0" arg:[0-7]+
-       / code:"x" arg:( [0-9a-fA-F] [0-9a-fA-F] )
-       / code:"u" arg:( [0-9a-fA-F] [0-9a-fA-F] [0-9a-fA-F] [0-9a-fA-F] )
-       / code:"0" arg:""? )
+       / control_escape
+       / octal_escape
+       / hex_escape
+       / unicode_escape
+       / null_escape )
   charset_range_escape <- "\\" esc:(
          code:[bfnrtv] arg:""?
-       / code:"c" arg:[a-zA-Z]
-       / code:"0" arg:[0-7]+
-       / code:"x" arg:( [0-9a-fA-F] [0-9a-fA-F] )
-       / code:"u" arg:( [0-9a-fA-F] [0-9a-fA-F] [0-9a-fA-F] [0-9a-fA-F] )
-       / code:"0" arg:""? )
+       / control_escape
+       / octal_escape
+       / hex_escape
+       / unicode_escape
+       / null_escape )
   charset_literal <- ( ""? literal:[^\\\]] )
                    / ( literal:"\\" &"c" )
                    / ( "\\" literal:[^bdDfnrsStvwW] )
@@ -44,11 +44,17 @@ grammar JavascriptRegexp
             / literal <Literal>
   escape <- "\\" esc:(
          code:[bBdDfnrsStvwW1-9] arg:""?
-       / code:"c" arg:[a-zA-Z]
-       / code:"0" arg:[0-7]+
-       / code:"x" arg:( [0-9a-fA-F] [0-9a-fA-F] )
-       / code:"u" arg:( [0-9a-fA-F] [0-9a-fA-F] [0-9a-fA-F] [0-9a-fA-F] )
-       / code:"0" arg:""? )
+       / control_escape
+       / octal_escape
+       / hex_escape
+       / unicode_escape
+       / null_escape )
   literal <- ( ""? literal:[^|\\/.\[\(\)?+*$^] )
            / ( literal:"\\" &"c" )
            / ( "\\" literal:. )
+
+  control_escape <- code:"c" arg:[a-zA-Z]
+  octal_escape <- code:"0" arg:[0-7]+
+  hex_escape <- code:"x" arg:( [0-9a-fA-F] [0-9a-fA-F] )
+  unicode_escape <- code:"u" arg:( [0-9a-fA-F] [0-9a-fA-F] [0-9a-fA-F] [0-9a-fA-F] )
+  null_escape <- code:"0" arg:""?