koa connects to mongodb database time error Unexpected token import, has been introduced into babel

server.js

const db = require("./mongodb/db");

const Koa = require("koa");
const webpack = require("webpack");
const merge = require("webpack-merge");

const KoaRouter = require("koa-router")();

const Monk = require("monk");
const schema = require("./mongodb/schema");

const opn = require("opn");
const config = merge(require("../config/webpack.config.dev"));
const appConfig = require("../app.config");
const currentIP = require("ip").address();
const uri = `http://${currentIP}:${appConfig.appPort}`;
const clientCompiler = webpack(config);
const devMiddleware = webpackDevMiddleware(clientCompiler, {
    publicPath: config.output.publicPath,
    headers: {"Access-Control-Allow-Origin": "*"},
    stats: {
        colors: true,
        modules: false,
    },
    noInfo: false,
});
// koa server
const app = new Koa();
// dateBase.connect();
db.connect((err) => {
    if (err) throw err;

    console.log("success");
});

devMiddleware.waitUntilValid(() => {
    // console.log("> Listening at " + uri + "\n");
    // opn(uri)
});

// 
app.on("error", (err) => {
    console.error("Server error: \n%s\n%s ", err.stack || "");
});

app.listen(appConfig.appPort);

schema.js

import mongoose from "mongoose";
const Schema = mongoose.Schema;

const UserModel = new Schema({
    name: String,
});

const User = mongoose.model("user", UserModel);

module.exports = {
    User
};

.babelrc

{
  "presets": [
    "@babel/preset-env",
    "@babel/preset-react"
  ],
  "plugins": [
    "react-hot-loader/babel"
  ]
}

the front-end page can be introduced with import, but the code on the server side cannot be
because the study is not in-depth, so I don"t know what the problem is. Please give me your advice