Create your own BLINK [Solana Tutorial]

const port = 3000;
import express from "express";
import bodyParser from "body-parser";
import cors from "cors";
import {
  Connection,
  LAMPORTS_PER_SOL,
  PublicKey,
  SystemProgram,
  Transaction,
  clusterApiUrl,
} from "@solana/web3.js";

const app = express();

const corsOptions = {
  origin: "*",
  credentials: true, //access-control-allow-credentials:true
  optionSuccessStatus: 200,
};

app.use(bodyParser.json());
app.use(bodyParser.urlencoded({ extended: true }));
app.use(cors(corsOptions));

app.get("/api/donate", (req, res) => {
  const response = {
    icon: "https://cdn-icons-png.flaticon.com/128/10880/10880476.png",
    description: "Donation",
    title: "Please donate me",
    label: "Donate me",
    error: "Blink don't not work",
    links: {
      actions: [
        {
          label: "Donald Trump (1.57x) - 0.0001 SOL",
          href: "http://localhost:3000/api/donate?amount=0.0001",
        },
        {
          label: "Joe Biden (3.75x) - 0.0002 SOL",
          href: "http://localhost:3000/api/donate?amount=0.0002",
        },
        {
          label: "Kamala Harris (8x) - 0.0003 SOL",
          href: "http://localhost:3000/api/donate?amount=0.0003",
        },
        {
          label: "Michelle Obama (17x) - 0.0004 SOL",
          href: "http://localhost:3000/api/donate?amount=0.0004",
        },
        {
          label: "Robert F. Kennedy Jr. (36x) - 0.0005 SOL",
          href: "http://localhost:3000/api/donate?amount=0.0005",
        },
      ],
    },
  };
  res.json(response);
});

app.post("/api/donate", async (req, res) => {
  const connection = new Connection(
    "",
  );
  const receiptAddress = "";
  const address = req.body.account;
  const amount = req.query.amount || 0.0001;
  const ixs = SystemProgram.transfer({
    fromPubkey: new PublicKey(address),
    toPubkey: new PublicKey(receiptAddress),
    lamports: amount * LAMPORTS_PER_SOL,
  });
  
  const tx = new Transaction();
  tx.add(ixs);
  tx.feePayer = new PublicKey(address);
  tx.recentBlockhash = (
    await connection.getLatestBlockhash({ commitment: "finalized" })
  ).blockhash;
  const serializeTrx = tx
    .serialize({ requireAllSignatures: false })
    .toString("base64");

  const response = {
    transaction: serializeTrx,
    message: address,
  };
  res.json(response);
});

app.options("/api/donate", async (req, res) => {
  
  const response = {
    transaction: "",
    message: "Options ",
  };
  res.json(response);
});

app.listen(port, () => {
  console.log(`Example app listening on port ${port}`);
});