Ethereum: Create OP_RETURN tx with Bitcoinjs-lib

Also, make sure you have a basic understanding of the Ethereum blockchain and its key concepts, such as transactions, outputs, and addresses.

Creating an OP_RETURN Transaction

Here is an example code snippet that shows how to create an OP_RETURN transaction with Bitcoin.js:

var bitcoin = require('bitcoinjs-lib');
var tx = new bitcoin.Transaction();
// Define the form input (who pays) [previous transaction hash, output index]
tx.addInput({
previousTransactionHash: 'your_previous_transaction_hash',
index: 0
}, {
ordinalNumber: 1,
value: 10 // 10 satoshis
});
// Define the data to be sent in the output (OP_RETURN)
tx.addOutput({
address: 'your_op_return_address',
type: 'op_return',
data: "Your OP_RETURN transaction description"
});

In this example, we create a new transaction and add two inputs:

• The first input is an empty transaction that refers to your previous transaction (we will generate it later).

• The second input sends 10 satoshis (0.000001 BTC) to the recipient address.

Next, we define the data to be sent in the output, which is the OP_RETURN transaction itself. Here you can describe what you want to send as a small amount of data.

Generating a Reference Transaction

To create an OP_RETURN input that references your previous transaction, you need to generate a reference transaction. Here's how to do it:

// Generate a new transaction (output)
var tx = new bitcoin.Transaction();
tx.addInput({
previousTransactionHash: 'your_previous_transaction_hash',
index: 0
}, {
ordinalNumber: 1,
value: 10 // 10 satoshis
});
// Create a reference transaction that references the output
tx.addOutput({
address: 'your_op_return_address',
type: 'op_return',
data: "Your OP_RETURN transaction description"
}).addReference({
previousTransactionHash: tx.hash(),
sequenceNumber: 2,
value: 1 // 0.000001 BTC
});

In this example, we generate a new output with an address and data. Then, we create a reference input that references the original output.

Putting it all together

Now that you have created both inputs (the empty transaction and the reference transaction), let's put it all together:

var bitcoin = require('bitcoinjs-lib');
var tx = new bitcoin.Transaction();
// Add form input (which pays) [previous transaction hash, index ...
tx.addInput({
previousTransactionHash: 'your_previous_transaction_hash',
index: 0
}, {
ordinalNumber: 1,
value: 10 // 10 satoshis
});
// Define the data to be sent in the output (OP_RETURN)
tx.addOutput({
address: 'your_op_return_address',
type: 'op_return',
data: "Your OP_RETURN transaction description"
});

Combining it all into one function

Here is an example of how everything can be combined into one function: