我正在使用失眠症，我想让它把我在指南针中添加的用户名发送给我，但是当我这样做的时候，它却返回为null。
我一直在绞尽脑汁，但没有成功。

这是我的index.js

import cors from "cors";
import mongoose from "mongoose";
import express from "express";
import bodyParser from "body-parser";
import * as dotenv from 'dotenv'
import morgan from "morgan";
import { fileURLToPath } from "url";
import path from "path"
import { userRouter } from "./controllers/auth.js";

/* CONFIGURATIONS */

const __filename = fileURLToPath(import.meta.url);
const __dirname = path.dirname(__filename);
dotenv.config({ debug: true });

const app = express();

app.use(express.json());
app.use(morgan("common"));
app.use(bodyParser.json({limit:"30mb", extended:true}));
app.use(bodyParser.urlencoded({limit:"30mb", extended:true}));
app.use(cors());

/* ROUTES */

app.use("/auth", userRouter)

 /* MONGOOSE SETUP */

 const PORT = process.env.PORT;
 mongoose.connect(process.env.MONGO_URL, {
    useNewUrlParser: true,
    useUnifiedTopology: true,
 }).then(() => {
    app.listen(PORT,() => console.log(`Server Started! On Port: ${PORT}`))
}).catch((error) => console.log(`${error} did not connect`))

我的auth.js

import express from "express";
import jwt from "jsonwebtoken"
import UserModel from "../models/user.js"

const router = express.Router();

/* REGISTER USER */

router.post("/register", async(req,res) => {

    const { username, password } = req.body;

    const user = await UserModel.findOne({ username:username });
    res.json(user)
});

export { router as userRouter };

我的模型/架构

import mongoose from "mongoose";

const { Schema } = mongoose;

const UserSchema = new Schema({
    username: {
        type: String,
        required: true,
        unique: true
    },
    password: {
        type: String,
        required: true,
    }
})

const UserModel = mongoose.model('Users', UserSchema)
export default UserModel

This is the respose in insomniaThis is the info I added in compass
我不知道我的错误是在“export { router as userRouter }”还是“app.use（“/auth”，userRouter）”中