Add exponential operator

Fixes #825

js/lib/beautify.js

@@ -1567,7 +1567,7 @@
         var digit_oct = /[01234567]/;
         var digit_hex = /[0123456789abcdefABCDEF]/;
 
-        var punct = ('+ - * / % & ++ -- = += -= *= /= %= == === != !== > < >= <= >> << >>> >>>= >>= <<= && &= | || ! ~ , : ? ^ ^= |= :: =>').split(' ');
+        var punct = ('+ - * / % & ++ -- = += -= *= /= %= == === != !== > < >= <= >> << >>> >>>= >>= <<= && &= | || ! ~ , : ? ^ ^= |= :: => **').split(' ');
         // words which should always start on new line.
         this.line_starters = 'continue,try,throw,return,var,let,const,if,switch,case,default,for,while,break,function,import,export'.split(',');
         var reserved_words = this.line_starters.concat(['do', 'in', 'else', 'get', 'set', 'new', 'catch', 'finally', 'typeof', 'yield', 'async', 'await']);

js/test/generated/beautify-javascript-tests.js

@@ -279,6 +279,12 @@ function run_javascript_tests(test_obj, Urlencoded, js_beautify, html_beautify,
             '})');
 
 
+
+        // ES7 exponential
+        bt('x ** 2');
+        bt('x ** -2');
+
+
         // End With Newline - (eof = "\n")
         opts.end_with_newline = true;
         test_fragment('', '\n');

python/jsbeautifier/__init__.py

@@ -1419,7 +1419,7 @@ class Tokenizer:
     digit_bin = re.compile('[01]')
     digit_oct = re.compile('[01234567]')
     digit_hex = re.compile('[0123456789abcdefABCDEF]')
-    punct = ('+ - * / % & ++ -- = += -= *= /= %= == === != !== > < >= <= >> << >>> >>>= >>= <<= && &= | || ! ~ , : ? ^ ^= |= :: =>').split(' ')
+    punct = ('+ - * / % & ++ -- = += -= *= /= %= == === != !== > < >= <= >> << >>> >>>= >>= <<= && &= | || ! ~ , : ? ^ ^= |= :: => **').split(' ')
 
     # Words which always should start on a new line
     line_starters = 'continue,try,throw,return,var,let,const,if,switch,case,default,for,while,break,function,import,export'.split(',')

python/jsbeautifier/tests/generated/tests.py

@@ -75,6 +75,10 @@ def unicode_char(value):
             '    implementation();\n' +
             '})')
 
+        # ES7 exponential
+        bt('x ** 2')
+        bt('x ** -2')
+
         # End With Newline - (eof = "\n")
         self.options.end_with_newline = true
         test_fragment('', '\n')

test/data/javascript/tests.js

@@ -33,6 +33,13 @@ exports.test_data = {
             '})'
           ]}
         ]
+    }, {
+        name: "ES7 exponential",
+        description: "ES7 exponential",
+        tests: [
+          { unchanged: 'x ** 2' },
+          { unchanged: 'x ** -2' }
+        ]
     }, {
         name: "End With Newline",
         description: "",