无法在 heroku 上 GET / MERN 堆栈部署

如何解决无法在 heroku 上 GET / MERN 堆栈部署

嗨，我在尝试将我的 mern 堆栈部署到 heroku 时遇到了问题。我尝试部署它的每一种方式我都得到相同的错误，获取错误无法获取 /。我已经完成了教程，但仍然没有运气

这是我的服务器。 js文件

const express = require("express");
const mongoose = require("mongoose");
const bodyParser = require("body-parser");
const passport = require("passport");

const users = require("./routes/api/users");
const payees = require("./routes/api/payees");
const transactions = require("./routes/api/transactions");

const path = require('path')

const app = express();

// Bodyparser middleware
app.use(
  bodyParser.urlencoded({
    extended: false
  })
);
app.use(bodyParser.json());

// DB Config
const db = require("./config/keys").mongoURI;

// Connect to MongoDB
mongoose
  .connect(
    db,{ useNewUrlParser: true }
  )
  .then(() => console.log("MongoDB successfully connected"))
  .catch(err => console.log(err));


app.use((req,res,next) => {
  res.header("Access-Control-Allow-Origin","*");
  res.header("Access-Control-Allow-Headers","Origin,X-Requested-With,Content-Type,Accept");
  next();
});

app.use(bodyParser.json());



// Passport middleware
app.use(passport.initialize());

// Passport config
require("./config/passport")(passport);

// Routes
app.use("/api/users",users);
app.use("/api/payees",payees);
app.use("/api/transactions",transactions)

if(process.env.NODE_ENV === 'production') {
  app.use(express.static(path.join(__dirname,'client','build')));

  app.get('*',(req,res) => {
    res.sendFile(path.join(__dirname,'build','index.html'))
  });

}

const port = process.env.PORT || 5000;

app.listen(port,() => console.log(`Server up and running on port ${port} !`));

module.exports = { app };

这是我的 package.json 文件

{
  "name": "STUBANK","version": "1.0.0","description": "","main": "server.js","scripts": {
    "client-install": "npm install --prefix client","start": "node server.js","server": "nodemon server.js","client": "npm start --prefix client","dev": "concurrently \"npm run server\" \"npm run client\"","test": "mocha","heroku-postbuild": "cd client && npm install && npm run build"
  },"author": "Ojini Jude","license": "MIT","dependencies": {
    "@material-ui/core": "^4.11.2","axios": "^0.21.1","bcryptjs": "^2.4.3","body-parser": "^1.18.3","chai": "^4.2.0","chai-http": "^4.3.0","classnames": "^2.2.6","crypto-random-string": "^3.3.0","dotenv": "^6.2.0","express": "^4.16.4","is-empty": "^1.2.0","jsonwebtoken": "^8.5.1","jwt-decode": "^3.1.2","mdbreact": "^5.0.1","mocha": "^8.2.1","mongoose": "^5.3.6","particles-bg": "^2.5.0","passport": "^0.4.1","passport-jwt": "^4.0.0","password-validator": "^5.1.1","react": "^17.0.1","react-bootstrap": "^1.4.0","react-dom": "^17.0.1","react-dropdown": "^1.9.0","react-redux": "^7.2.2","react-router-dom": "^5.2.0","react-scripts": "^4.0.1","react-search-box": "^2.0.2","react-search-field": "^1.2.0","react-select": "^3.1.1","redux": "^4.0.5","redux-thunk": "^2.3.0","supertest": "^6.0.1","validator": "^13.5.1"
  },"devDependencies": {
    "concurrently": "^4.1.2","nodemon": "^1.19.4"
  },"engines": {
    "node": "12.16.0"
  }
}

任何帮助将不胜感激。

file structure