Current Mailing List Thread: https://esdiscuss.org/topic/proposal-for-a-null-coalescing-operator
http://wikipedia.org/wiki/Null_coalescing_operator
Essentially x ?? y will return x when not null or undefined else it will return y.
A nice Javascript explanation of the current problems with using || that can cause unforeseen bugs:
stackoverflow.com/a/476445
Also an assignment operator ??= would be added.
Section 11.7 needs to add ?? and ??=
There also needs to be a section explaining the behavior.