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.
Answer Wiki. The only way to obtain the Command Block is through cheats. Do /give <playerid> command_block to give the player 1 command block. Remember, only players in Creative can program command blocks, although any player can activate redstone to use the command block. For instance, only a player in Creative can program a command block with /tp @p x y z while any player can then push the button that activates the command block and teleports the player.