feat(keyhandler): add onNodeRemove callback

src/GraphContext/index.js

@@ -1,4 +1,4 @@
-import React, { createContext, useEffect, useReducer } from 'react';
+import React, { createContext, useEffect, useReducer, useRef } from 'react';
 import PropTypes from 'prop-types';
 import isEqual from 'lodash.isequal';
 
@@ -7,6 +7,16 @@ import { setNodes, setEdges } from '../state/actions';
 
 export const GraphContext = createContext({});
 
+function usePrevious(value) {
+  const ref = useRef();
+
+  useEffect(() => {
+    ref.current = value;
+  });
+
+  return ref.current;
+}
+
 export const Provider = (props) => {
   const {
     onNodeClick,