Description Mark Macdonald 2014-01-27 11:00:14 EST

The ECMAScript 5 grammar permits extra commas in cases that were considered syntax errors in ES3:

Object literal:
> var foo = {
>   bar: 0,
>   qux: 1,   // extra comma
> };

Array literal:
> var arr = [1,2,];      // extra comma
> var arr = [1,2,,,,];   // several extra commas (only arrays allow this)

Orion's validator should provide a rule that flags these. The rule should be set to "Ignore" by default (we should assume authors are targeting ES5, not ES3).