What causes node to return 'navigator is not defined'

问题

I am using npm package geolocation but I have also used logic such as if (navigator.geolocation) and I keep getting ReferenceError: navigator is not defined

As such?

var geo = function(){ //using Mr. Concolato's example
   function geolocation(){
      if(geo.geolocation()){//blah
        navigator.geolocation.getCurrentPosition(coords)
        console.log(coords);
      }
   }
}

来源：https://stackoverflow.com/questions/27573293/what-causes-node-to-return-navigator-is-not-defined