This plug-in depends on nodeJS, version 6.4.0 or higher. The node command must be available in $PATH. To check whether this is the case, enter:

$ which node

If this command does not return the path of the node executable, then you need to either install it or add its location to $PATH. If node is available, make sure you check its version, since the version installed by default on Ubuntu systems is too old:

$ node -v

If the version number is less than 6.4.0, then you need to replace it with a newer version. For advice on how to do this on Ubuntu, see (for example) this page.