server.js

const express = require("express");
const connectDB = require("./config/db");
const cors = require("cors")
const app = express();
const PORT = process.env.PORT || 5000;
const path = require('path')

//connect database
connectDB();

app.use(express.json({ extended: false }));
app.use(cors())
//routes
app.use("/api/user", require("./routes/api/user"));
app.use("/api/profile", require("./routes/api/profile"));
app.use("/api/posts", require("./routes/api/posts"));
app.use("/api/auth", require("./routes/api/auth"));

// serve static assets in production
if (process.env.NODE_ENV === 'production') {
  // set static folder
  app.use(express.static('client/build'));

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

}

app.listen(PORT, (err) => {
  if (err) {
    console.log(err);
  } else {
    console.log(`Server is listening at ${PORT}`);
  }
});