Initial commit

.gitignore

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+index.cjs
+index.js
+index.d.ts
+node_modules
+dist
+.yarn/*
+!.yarn/patches
+!.yarn/plugins
+!.yarn/releases
+!.yarn/sdks
+!.yarn/versions
+
+.turbo
+**/.turbo
+**/.eslintcache
+
+.env
+.ipynb_checkpoints
+

LICENSE

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+MIT License
+
+Copyright (c) 2024 LangChain
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

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+# LangGraph Starter Template
+
+This repo offers the basic code structure to get started building LangGraph workflows in JavaScript within LangGraph studio.
+
+
+## Repo Structure
+
+```txt
+├── LICENSE
+├── README.md
+├── jest.config.js # Test configuration
+├── .env # Define environment variables. Can copy over from .env.example
+├── langgraph.json # LangGraph studio configuration
+├── my-app
+│   ├── graph.ts # Graph / workflow definition
+│   └── index.ts
+├── package.json # Define the project dependencies
+├── tests # Add any tests you'd like here
+│   ├── integration
+│   │   └── graph.int.test.ts
+│   └── unit
+│       └── graph.test.ts
+├── tsconfig.json # Typescript-specific configuration
+└── yarn.lock
+```

jest.config.js

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+export default {
+  preset: "ts-jest/presets/default-esm",
+  moduleNameMapper: {
+    "^(\\.{1,2}/.*)\\.js$": "$1",
+  },
+  transform: {
+    "^.+\\.tsx?$": [
+      "ts-jest",
+      {
+        useESM: true,
+      },
+    ],
+  },
+  extensionsToTreatAsEsm: [".ts"],
+};

langgraph.json

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+{
+  "node_version": "v20.16.0",
+  "dockerfile_lines": [],
+  "dependencies": ["."],
+  "graphs": {
+    "agent": "./graph.ts:graph"
+  },
+  "env": ".env"
+}

my-app/graph.ts

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+/**
+ * Empty LangGraph Template
+ *
+ * Make this code your own!
+ */
+
+import { StateGraph, Annotation } from "@langchain/langgraph";
+
+/**
+ * The State defines three things:
+ * 1. The structure of the graph's state (which "channels" are available to read/write)
+ * 2. The default values for the state's channels
+ * 3. The reducers for the state's channels. Reducers are functions that determine how to apply updates to the state.
+ * See [Reducers](https://langchain-ai.github.io/langgraphjs/concepts/low_level/#reducers) for more information.
+ */
+const State = Annotation.Root({
+  // Example of a channel that will be replaced any time
+  // it is written to
+  input: Annotation<string>(),
+  // Example of a channel that is "append-only"
+  stringList: Annotation<string[]>({
+    reducer: (x: string[], y: string[]) => x.concat(y),
+    default: () => [],
+  }),
+});
+
+type StateT = typeof State.State;
+
+// Define nodes, these do the work:
+
+const callModel = async (state: StateT) => {
+  // Do some work... (e.g. call an LLM)
+  return { stringList: [state.input, "b", "c"] };
+};
+
+// Define conditional edge logic:
+
+/**
+ * Routing function: Determines whether to continue research or end the workflow.
+ * This function decides if the gathered information is satisfactory or if more research is needed.
+ *
+ * @param state - The current state of the research workflow
+ * @returns Either "callModel" to continue research or END to finish the workflow
+ */
+export const _route = (state: StateT): "__end__" | "callModel" => {
+  if (state.stringList.length > 0) {
+    return "__end__";
+  }
+  // Loop back
+  return "callModel";
+};
+
+// Finally, create the graph itself.
+const workflow = new StateGraph(State)
+  // Add the nodes to do the work.
+  // Chaining the nodes together in this way
+  // updates the types of the StateGraph instance
+  // so you have static type checking when it comes time
+  // to add the edges.
+  .addNode("callModel", callModel)
+  // Regular edges mean "always transition to node B after node A is done"
+  // The "__start__" and "__end__" nodes are "virtual" nodes that are always present
+  // and represent the beginning and end of the workflow.
+  .addEdge("__start__", "callModel")
+  .addConditionalEdges("callModel", _route);
+
+export const graph: any = workflow.compile();

package.json

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+{
+  "name": "example-graph",
+  "version": "0.0.1",
+  "description": "A starter template for creating a LangGraph workflow.",
+  "main": "graph.ts",
+  "author": "Your Name",
+  "license": "MIT",
+  "private": true,
+  "type": "module",
+  "scripts": {
+    "build": "tsc",
+    "clean": "rm -rf dist",
+    "test": "node --experimental-vm-modules node_modules/jest/bin/jest.js --testPathPattern=\\.test\\.ts$ --testPathIgnorePatterns=\\.int\\.test\\.ts$",
+    "test:int": "node --experimental-vm-modules node_modules/jest/bin/jest.js --testPathPattern=\\.int\\.test\\.ts$",
+    "format": "prettier --write ."
+  },
+  "dependencies": {
+    "@langchain/langgraph": "^0.0.34",
+    "ts-node": "^10.9.2"
+  },
+  "devDependencies": {
+    "@langchain/openai": "^0.2.7",
+    "@tsconfig/recommended": "^1.0.7",
+    "@types/jest": "^29.5.0",
+    "jest": "^29.7.0",
+    "prettier": "^3.3.3",
+    "ts-jest": "^29.1.0",
+    "typescript": "^5.3.3"
+  }
+}

tests/integration/graph.int.test.ts

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+import { describe, it, expect } from "@jest/globals";
+import { graph } from "../../my-app/graph.js";
+describe("Researcher", () => {
+  it("Simple runthrough", async () => {
+    const res = await graph.invoke({ input: "ExampleInput" });
+    expect(res.stringList).toEqual(["ExampleInput", "b", "c"]);
+  }, 100_000);
+});

tests/unit/graph.test.ts

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+import { describe, it, expect } from "@jest/globals";
+import { _route } from "../../my-app/graph.js";
+describe("Routers", () => {
+  it("Test route", async () => {
+    const res = _route({ input: "ExampleInput", stringList: [] });
+    expect(res).toEqual("callModel");
+  }, 100_000);
+});

tsconfig.json

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+{
+  "extends": "@tsconfig/recommended",
+  "compilerOptions": {
+    "target": "ES2021",
+    "lib": ["ES2021", "ES2022.Object", "DOM"],
+    "module": "NodeNext",
+    "moduleResolution": "nodenext",
+    "esModuleInterop": true,
+    "declaration": true,
+    "noImplicitReturns": true,
+    "noFallthroughCasesInSwitch": true,
+    "noUnusedLocals": true,
+    "noUnusedParameters": true,
+    "useDefineForClassFields": true,
+    "strictPropertyInitialization": false,
+    "allowJs": true,
+    "strict": true,
+    "strictFunctionTypes": false,
+    "outDir": "dist",
+    "types": ["jest", "node"],
+    "resolveJsonModule": true
+  },
+  "include": ["**/*.ts", "**/*.js"],
+  "exclude": ["node_modules", "dist"]
+}