Trailing commas not supported inside Array constructor

[aptivaman]

In evaljs, trailing commas are allowed in array declarations, but when using Array constructors, it causes a crash:

import dukpy
testArray1 = '''
var array1 = [1, 2, 3, ];
array1.reduce(function(a, b) { return a + b; }, 0);
'''
print(dukpy.evaljs(testArray1))

testArray2 = '''
var array2 = new Array(1, 2, 3, );
array2.reduce(function(a, b) { return a + b; }, 0);
'''
print(dukpy.evaljs(testArray2))

~ $ python3 test.py
6
Traceback (most recent call last):
  File "test.py", line 12, in <module>
    print(dukpy.evaljs(testArray2))
  File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/dukpy/evaljs.py", line 134, in evaljs
    return JSInterpreter().evaljs(code, **kwargs)
  File "/Library/Frameworks/Python.framework/Versions/3.8/lib/python3.8/site-packages/dukpy/evaljs.py", line 57, in evaljs
    res = _dukpy.eval_string(self, jscode, jsvars)
_dukpy.JSRuntimeError: SyntaxError: empty expression not allowed (line 2)
	src/pyduktape.c:2
	duk_js_compiler.c:4731

[webknjaz]

Does duktape support this?

[aptivaman]

According to this, it is "Future Work" https://github.com/svaarala/duktape/blob/master/doc/json.rst#trailing-commas-in-objects-and-arrays

[webknjaz]

Well, then it's not a dukpy's bug. Once they implement and release it, dukpy would only need to update the embedded version of duktape.