support debugger statement (closes #278)

Author: mishoo

lib/parse-js.js

@@ -65,6 +65,7 @@ var KEYWORDS = array_to_hash([
         "catch",
         "const",
         "continue",
+        "debugger",
         "default",
         "delete",
         "do",
@@ -93,7 +94,6 @@ var RESERVED_WORDS = array_to_hash([
         "byte",
         "char",
         "class",
-        "debugger",
         "double",
         "enum",
         "export",

lib/process.js

@@ -139,6 +139,9 @@ function ast_walker() {
                 "function": function(name, args, body) {
                         return [ this[0], name, args.slice(), MAP(body, walk) ];
                 },
+                "debugger": function() {
+                        return [ this[0] ];
+                },
                 "defun": function(name, args, body) {
                         return [ this[0], name, args.slice(), MAP(body, walk) ];
                 },
@@ -1539,6 +1542,7 @@ function gen_code(ast, options) {
                 "string": encode_string,
                 "num": make_num,
                 "name": make_name,
+                "debugger": function(){ return "debugger" },
                 "toplevel": function(statements) {
                         return make_block_statements(statements)
                                 .join(newline + newline);

test/unit/compress/expected/issue278.js

@@ -0,0 +1 @@
+if(!x)debugger

test/unit/compress/test/issue278.js

@@ -0,0 +1 @@
+if (!x) debugger;