anza-xyz_wallet-adapter/packages/starter/example/src/components/SendTransaction.tsx

import { Button } from '@mui/material';
import { useConnection, useWallet } from '@solana/wallet-adapter-react';
import type { TransactionSignature } from '@solana/web3.js';
import { PublicKey, Transaction, TransactionInstruction } from '@solana/web3.js';
import React, { useCallback, type FC } from 'react';
import { useNotify } from './useNotify';

export const SendTransaction: FC = () => {
    const { connection } = useConnection();
    const { publicKey, sendTransaction } = useWallet();
    const notify = useNotify();

    const onClick = useCallback(async () => {
        let signature: TransactionSignature | undefined = undefined;
        try {
            if (!publicKey) throw new Error('Wallet not connected!');

            const {
                context: { slot: minContextSlot },
                value: { blockhash, lastValidBlockHeight },
            } = await connection.getLatestBlockhashAndContext();

            const transaction = new Transaction({
                feePayer: publicKey,
                recentBlockhash: blockhash,
            }).add(
                new TransactionInstruction({
                    data: Buffer.from('Hello, from the Solana Wallet Adapter example app!'),
                    keys: [],
                    programId: new PublicKey('MemoSq4gqABAXKb96qnH8TysNcWxMyWCqXgDLGmfcHr'),
                })
            );

            signature = await sendTransaction(transaction, connection, { minContextSlot });
            notify('info', 'Transaction sent:', signature);

            await connection.confirmTransaction({ blockhash, lastValidBlockHeight, signature });
            notify('success', 'Transaction successful!', signature);
        } catch (error: any) {
            notify('error', `Transaction failed! ${error?.message}`, signature);
        }
    }, [publicKey, connection, sendTransaction, notify]);

    return (
        <Button variant="contained" color="secondary" onClick={onClick} disabled={!publicKey}>
            Send Transaction (devnet)
        </Button>
    );
};