create server api

+const express = require("express");
+const router = express.Router();
+const AssistantV2 = require("ibm-watson/assistant/v2");
+const { IamAuthenticator } = require("ibm-watson/auth");
+
+const authenticator = new IamAuthenticator({
+  apikey: process.env.WATSON_ASSISTANT_APIKEY,
+});
+
+const assistant = new AssistantV2({
+  version: "2019-02-28",
+  authenticator: authenticator,
+  url: process.env.WATSON_ASSISTANT_URL,
+});
+
+router.get("/session", async (req, res) => {
+  try {
+    const session = await assistant.createSession({
+      assistantId: process.env.WATSON_ASSISTANT_ID,
+    });
+    res.json(session["result"]);
+  } catch (err) {
+    res.send("There was an error processing your request.");
+    console.log(err);
+  }
+});
+
+router.post("/message", async (req, res) => {
+  let payload = {
+    assistantId: process.env.WATSON_ASSISTANT_ID,
+    sessionId: req.headers.session_id,
+    input: {
+      message_type: "text",
+      text: req.body.input,
+    },
+  };
+
+  try {
+    const message = await assistant.message(payload);
+    res.json(message["result"]);
+  } catch (err) {
+    res.send("There was an error processing your request.");
+    console.log(err);
+  }
+});
+
+module.exports = router;

+const express = require("express");
+const dotenv = require("dotenv");
+const app = express();
+
+dotenv.config();
+
+app.use(express.json());
+
+const watsonRoute = require("./routes/api/server_watson");
+app.use("/api/watson", watsonRoute);
+
+const port = process.env.PORT || 5000;
+app.listen(port, () => {
+    console.log(`Server is listening http://localhost:${port}`);
+});