Hi, GraphAdjacency has this in the impl: return this.http.get(url).map((vertices:any) => { return graphService.fromJSON(vertices[0], target.http); }); What's the idea behind this.http vs. target.http? `target` is the class where the decorator is present, and `this` is the instance. I can understand that it needs to be somewhere, but then why pass it in the parameter? And how does the value get to the model class? fromJSON() sets it on the instance. Ondra -- -- Ondrej Zizka, Windup project, Brno