After brief investigation I found that there are no any related properties in CSOM's/JSOM's List object.
But you can alway get list's Schema XML and get practically any information from there. Needed property is stored as attribute and has name EmailAlias.
So, the solution was pretty simple:
Using this approach you can also get other properties as well. Some of them are also included in JSOM's object as properties but some may not.