examples[minor]: Port langchain examples code to run ts files in exam…

…ples (#383)

examples/package.json

@@ -1,6 +1,10 @@
 {
   "name": "examples",
+  "type": "module",
   "description": "Dependencies for LangGraph examples.",
+  "scripts": {
+    "start": "tsx --experimental-wasm-modules -r dotenv/config src/index.ts"
+  },
   "devDependencies": {
     "@langchain/anthropic": "^0.2.15",
     "@langchain/cloudflare": "^0.0.7",
@@ -20,6 +24,7 @@
     "langchain": "^0.2.16",
     "pg": "^8.11.0",
     "tslab": "^1.0.22",
+    "tsx": "^4.18.0",
     "uuid": "^10.0.0",
     "zod": "^3.23.8",
     "zod-to-json-schema": "^3.23.2"

examples/src/index.ts

@@ -0,0 +1,56 @@
+import path from "path";
+import url from "url";
+import { awaitAllCallbacks } from "@langchain/core/callbacks/promises";
+
+const [exampleName, ...args] = process.argv.slice(2);
+
+if (!exampleName) {
+  console.error("Please provide path to example to run");
+  process.exit(1);
+}
+
+// Allow people to pass all possible variations of a path to an example
+// ./src/foo.ts, ./dist/foo.js, src/foo.ts, dist/foo.js, foo.ts
+let exampleRelativePath = exampleName;
+
+if (exampleRelativePath.startsWith("./examples/")) {
+  exampleRelativePath = exampleName.slice(11);
+} else if (exampleRelativePath.startsWith("examples/")) {
+  exampleRelativePath = exampleName.slice(9);
+}
+
+if (exampleRelativePath.startsWith("./src/")) {
+  exampleRelativePath = exampleRelativePath.slice(6);
+} else if (exampleRelativePath.startsWith("./dist/")) {
+  exampleRelativePath = exampleRelativePath.slice(7);
+} else if (exampleRelativePath.startsWith("src/")) {
+  exampleRelativePath = exampleRelativePath.slice(4);
+} else if (exampleRelativePath.startsWith("dist/")) {
+  exampleRelativePath = exampleRelativePath.slice(5);
+}
+
+let runExample;
+try {
+  ({ run: runExample } = await import(
+    path.join(
+      path.dirname(url.fileURLToPath(import.meta.url)),
+      exampleRelativePath
+    )
+  ));
+} catch (e) {
+  console.log(e);
+  throw new Error(`Could not load example ${exampleName}: ${e}`);
+}
+
+if (runExample) {
+  const maybePromise = runExample(args);
+
+  if (maybePromise instanceof Promise) {
+    maybePromise
+      .catch((e) => {
+        console.error(`Example failed with:`);
+        console.error(e);
+      })
+      .finally(() => awaitAllCallbacks());
+  }
+}

examples/tsconfig.json

@@ -0,0 +1,31 @@
+{
+  "extends": "@tsconfig/recommended",
+  "compilerOptions": {
+    "outDir": "dist",
+    "lib": [
+      "ES2021",
+      "ES2022.Object",
+      "DOM"
+    ],
+    "target": "ES2021",
+    "module": "nodenext",
+    "sourceMap": true,
+    "allowSyntheticDefaultImports": true,
+    "baseUrl": "./src",
+    "declaration": true,
+    "noImplicitReturns": true,
+    "noFallthroughCasesInSwitch": true,
+    "noUnusedParameters": true,
+    "useDefineForClassFields": true,
+    "strictPropertyInitialization": false
+  },
+  "exclude": [
+    "node_modules/",
+    "dist/",
+    "tests/"
+  ],
+  "include": [
+    "*.ts",
+    "./src"
+  ]
+}