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.
Place a command block. Check your inventory and look for the command blocks you just created. The icon is a brown, patterned box with grey control panels on each side. Move the command blocks to your quick slot and place one on the ground, just as you would any item.. Enter a command. You can enter just about any command in the command block's text field, then press Done to save it in the block. There's a long list of commands included below, but try summon Sheep for your first experiment.