JavaScript makes use of automatic semicolon insertion (ASI), and there are only certain scenarios where they are required. The engine used for the shell integration does not support this, and says scripts are invalid without them.

The same applies to multiple var declarations using commas

var test1 = {}
, test2 = new Date();

Perfectly valid in engines such as v8, however the shell states

2015-12-01T16:32:53.208+0000 E QUERY SyntaxError: Unexpected token ,

I've moved from RoboMongo to MongoChef due to lack of support for Mongo v3, and this is something that I sorely miss.