Knockout includes a function called ko.isObservable() . You can call it like ko.isObservable(vm[key]) . Update from comment: Here is a function to determine if something is a computed observable: UPDATE: If you are using KO 2.1+ - then you can use ko.isComputed directly.
Command Block. The Command Block is a redstone-powered block that was made available in the 1.4 update for Minecraft. The Command Block will perform server Commands when attached to a redstone circuit. This block cannot be crafted, and only server operators are allowed to place and use them.
Once you have a command block, right click it to open it's GUI. Now, you must copy and paste the command from your browser into the game. Select the entire command from below, then right click and press 'copy'. Next, go back to your minecraft world, and paste the command you just copied into the command block.