Listen to new blocks

This example shows how to subscribe to new blocks.

It displays the block number every time a new block is seen by the node you are connected to.

NOTE: The example runs until you stop it with CTRL+C

const BN = require('bn.js');
const Api = require('@polkadot/api').default;
const WsProvider = require('@polkadot/api-provider/ws').default;
const provider = new WsProvider('ws://127.0.0.1:9944');
const api = new Api(provider);

function main () {
  console.log('Blocks will be shown as they come in, CTRL+C to stop:');
  api.chain.newHead((_, header) => {
    const bnBlockNumber = new BN(header.number, 16);

    console.log('#' + bnBlockNumber.toString(10));
  });
}

main();