Chapter 11: no Graph.js file

[Lingsa]

codes can't run
chaper11-3:load("Graph.js")

what is the path.push(s)?
function pathTo(v) { var source=0; if(!this.hasPathTo(v)){ return undefined; } var path=[]; for(var i=v; i !=source; i=this.edgeTo[i]) { path.push[i]; } path.push(s); return path; }