What is a Block Number?

A block number is a unique identifier for each block in the Ethereum blockchain. It represents the position of a block in the chain and is crucial for tracking transactions and the state of the blockchain.

Purpose of Getting the Current Block Number

Retrieving the current block number is essential for various applications, including:

  • Monitoring the blockchain's progress.
  • Synchronizing data with the latest state of the blockchain.
  • Implementing features that depend on the block number, such as time-based events.

Using Ethers.js to Get the Current Block Number

Ethers.js provides a simple method to get the current block number using the provider.getBlockNumber() function. This function returns the latest block number from the Ethereum network.

Syntax

const blockNumber = await provider.getBlockNumber();

- This method does not require any parameters and returns the current block number.

Sample Code for Getting the Current Block Number

Below is an example demonstrating how to get the current block number using Ethers.js:

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Ethers.js Get Current Block Number Example</title>
    <script src="https://cdn.jsdelivr.net/npm/ethers@5.7.0/dist/ethers.umd.min.js"></script>
</head>
<body>
    <h1>Get Current Block Number</h1>
    <button id="getBlockNumberButton">Get Current Block Number</button>
    <pre id="blockNumberOutput"></pre>

    <script>
        // Connect to the Ethereum network (default to mainnet)
        const provider = new ethers.providers.getDefaultProvider();

        document.getElementById('getBlockNumberButton').onclick = async function() {
            try {
                const blockNumber = await provider.getBlockNumber();
                document.getElementById('blockNumberOutput').innerText = 
                    "Current Block Number: " + blockNumber;
            } catch (error) {
                document.getElementById('blockNumberOutput').innerText = 
                    "Error: " + error.message;
            }
        };
    </script>
</body>
</html>

Conclusion

Getting the current block number using Ethers.js is straightforward with the provider.getBlockNumber() method. This allows developers to easily retrieve and display the latest block number, facilitating better interaction with the Ethereum blockchain.