feat(utils): getOutgoers function

example/SimpleGraph.js

@@ -1,6 +1,6 @@
 import React, { PureComponent } from 'react';
 
-import Graph, { isEdge, removeElements } from '../src';
+import Graph, { isEdge, removeElements, getOutgoers } from '../src';
 // import Graph from '../dist/ReactGraph';
 
 const SpecialNode = ({ data, onChange, styles }) => (
@@ -57,7 +57,7 @@ class App extends PureComponent {
   }
 
   onLoad(graphInstance) {
-    console.log('graph loaded:', this.graphInstance);
+    console.log('graph loaded:', graphInstance);
     window.rg = graphInstance;
 
     this.graphInstance = graphInstance;
@@ -89,6 +89,11 @@ class App extends PureComponent {
     }));
   }
 
+  onElementClick(element) {
+    console.log('click', element);
+    console.log('outgoers', getOutgoers(element, this.state.elements));
+  }
+
   onZoomIn() {
     this.graphInstance.zoomIn();
   }
@@ -107,7 +112,7 @@ class App extends PureComponent {
     return (
       <Graph
         elements={this.state.elements}
-        onElementClick={node => console.log('clicked', node)}
+        onElementClick={element => this.onElementClick(element)}
         onElementsRemove={elements => this.onElementsRemove(elements)}
         style={{ width: '100%', height: '100%' }}
         onLoad={graphInstance => this.onLoad(graphInstance)}

src/graph-utils.js

@@ -2,6 +2,15 @@ export const isEdge = element => element.source && element.target;
 
 export const isNode = element => !element.source && !element.target;
 
+export const getOutgoers = (node, elements) => {
+  if (!isNode(node)) {
+    return [];
+  }
+
+  const outgoerIds = elements.filter(e => e.source === node.id).map(e => e.target);
+  return elements.filter(e => outgoerIds.includes(e.id));
+};
+
 export const removeElements = (elements, elementsToRemove) => {
   const nodeIdsToRemove = elementsToRemove.filter(isNode).map(n => n.id);
 
@@ -12,7 +21,7 @@ export const removeElements = (elements, elementsToRemove) => {
       !nodeIdsToRemove.includes(e.source)
     );
   });
-}
+};
 
 export const parseElements = e => {
   e.type = e.type || 'default';

src/index.js

@@ -2,11 +2,13 @@ import ReactGraph from './ReactGraph';
 import {
   isNode as _isNode ,
   isEdge as _isEdge,
-  removeElements as _removeElements
+  removeElements as _removeElements,
+  getOutgoers as _getOutgoers
 } from './graph-utils';
 
 export const isNode = _isNode;
 export const isEdge = _isEdge;
 export const removeElements = _removeElements;
+export const getOutgoers = _getOutgoers;
 
 export default ReactGraph;