app.js

const express = require('express');
const app = express();
const paypal = require('paypal-rest-sdk');

const port = 3030;

paypal.configure({
  'mode': 'sandbox',
  'client_id': 'ASsfpwMvxaDpxysS-T_IrFQVx049T-UACrSh2ztukqgQfcSaKPUzzIXXszrehbYU6pDRjZJl3T9qjZSO',
  'client_secret': 'EGurON82iCfa0D-Sb21N31UDfA4BU_Y8wiBu9bJitkSjtbHzjtkRn1x7g2Q5UtBBAD0eaglQAUoYClUQ'
});



// Set our template engine of choice
app.set("view engine", "ejs");

app.use(express.static("public"));

// Basic Routes
app.get("/", (req, res) => {
  res.render('index');
});

app.post("/pay", (req, res) => {
const create_payment_json = {
    "intent": "sale",
    "payer": {
        "payment_method": "paypal"
    },
    "redirect_urls": {
      // you will need to replace localhost with your server url
        "return_url": "http://localhost/success",
        "cancel_url": "http://localhost/cancel"
    },
    "transactions": [{
        "item_list": {
            "items": [{
                "name": "Donation",
                "sku": "001",
                "price": "2.00",
                "currency": "USD",
                "quantity": 1
            }]
        },
        "amount": {
            "currency": "USD",
            "total": "2.00"
        },
        "description": "Supporting open source programming."
    }]
};

paypal.payment.create(create_payment_json, function (error, payment) {
    if (error) {
        throw error;
    } else {
        for(let i = 0; i < payment.links.length; i++){
          if(payment.links[i].rel === 'approval_url'){
            res.redirect(payment.links[i].href);
}
}
    }
});

});



app.get('/success', (req, res) => {
  const payerID = req.query.PayerID;
  const paymentID = req.query.paymentId;

  const execute_payment_json = {
    "payer_id": payerID,
    "transactions": [{
       "amount": {
          "currency": "USD",
          "total": "2.00"
}
}]
};

  paypal.payment.execute(paymentID, execute_payment_json, function (error, payment) {
    if (error) {
      console.log(error.response);
      throw error;
} else {
    console.log("Get Payment Response");
    console.log(JSON.stringify(payment));
    res.render('success');
}

});
});


app.get('/cancel', (req, res) => res.render('cancel'));

// Web Server
app.listen(3030, () => {
  console.log(`Listening at port ${port}`);
});