feat: solution for 'Повторный экзамен: Граф с рефлексией и доработкой'

src/index.ts

@@ -0,0 +1,10 @@
+import { app } from './langgraph';
+
+async function main() {
+  const result = await app.invoke({ input: 'Hello world' });
+  console.log('Final result:', result);
+}
+
+main().catch((err) => {
+  console.error('Error during execution:', err);
+});

src/langgraph.ts

@@ -0,0 +1,41 @@
+import { StateGraph } from 'langgraph';
+
+export type State = {
+  input: string;
+  output?: string;
+};
+
+const startFn = (state: State) => {
+  // The start node simply passes the initial state through.
+  return state;
+};
+
+const reflection = (state: State) => {
+  console.log('Reflection node:', state);
+  return state;
+};
+
+const rewriting = (state: State) => {
+  const newState = { ...state, output: state.input.toUpperCase() };
+  console.log('Rewriting node:', newState);
+  return newState;
+};
+
+const end = (state: State) => {
+  console.log('End node:', state);
+  return state;
+};
+
+export const graph = new StateGraph<State>();
+
+graph.addNode('start', startFn);
+graph.addNode('reflection', reflection);
+graph.addNode('rewriting', rewriting);
+graph.addNode('end', end);
+
+graph.setEntryPoint('start');
+graph.addEdge('start', 'reflection');
+graph.addEdge('reflection', 'rewriting');
+graph.addEdge('rewriting', 'end');
+
+export const app = graph.compile();