use echats force-oriented diagram to report to TypeError Cannot read property off of undefined
change the configuration (vue environment) in series
related codes
{
                    // name: "Les Miserables",
                    type: "graph",
                    layout: "force",   //**none**
                    data: this.graph.nodes,
                    links: this.graph.links,
                    categories: this.categories,
                    // draggable: true,
                    roam: true,
                    // symbolSize: 30,
                    edgeLength: [100,1000],
                    edgeSymbol: ["none", "arrow"],       //
                    focusNodeAdjacency: true,
                    itemStyle: {                  //
                        normal: {                  //
                            borderColor: "-sharpfff",
                            borderWidth: 1,
                            shadowBlur: 10,
                            shadowColor: "rgba(0, 0, 0, 0.3)",
                            fontSize: "8px"
                        }
                    },
                    ...
