Robomongo is a useful GUI tool for the management of MongoDB databases. It can be installed on different platforms like Windows, Mac OS X, Linux.
In Robomongo you can write the same JavaScript code as you can do in MongoDB shell. This tool provides autocompletion, syntax highlighting, different view modes(custom, tree, table, text), multiple opened tabs for a single database or for many databases.
Robomongo provides results for each statement from your code. This means that you can compare or view documents side by side. See the below image.
Also you can save your code in JavaScript files for later usage, using the commands from File menu (Save, Save As..., Open).