feat: Fixed the issue where the page reports an error when the graph returned by the interface is empty #162 (#1795)

…returned by the interface is empty #162

### What problem does this PR solve?

feat: Fixed the issue where the page reports an error when the graph
returned by the interface is empty #162

### Type of change


- [x] New Feature (non-breaking change which adds functionality)

web/src/pages/add-knowledge/components/knowledge-chunk/components/knowledge-graph/force-graph.tsx

 import { ElementDatum, Graph, IElementEvent } from '@antv/g6';
+import isEmpty from 'lodash/isEmpty';
 import { useCallback, useEffect, useMemo, useRef } from 'react';
 import { buildNodesAndCombos } from './util';
 
   const graphRef = useRef<Graph | null>(null);
 
   const nextData = useMemo(() => {
-    if (data) {
+    if (!isEmpty(data)) {
       const graphData = data;
       const mi = buildNodesAndCombos(graphData.nodes);
       return { edges: graphData.links, ...mi };
   }, [nextData]);
 
   useEffect(() => {
-    if (data) {
+    if (!isEmpty(data)) {
       render();
     }
   }, [data, render]);

web/src/pages/add-knowledge/components/knowledge-chunk/components/knowledge-graph/util.ts

+import { isEmpty } from 'lodash';
+
 class KeyGenerator {
   idx = 0;
   chars: string[] = [];
 }
 
 export const isDataExist = (data: any) => {
-  return data?.data && typeof data?.data !== 'boolean';
+  return (
+    data?.data && typeof data?.data !== 'boolean' && !isEmpty(data?.data?.graph)
+  );
 };
 
 export const buildNodesAndCombos = (nodes: any[]) => {