4-watch-blocks.ts

import { SDK } from "codechain-sdk";
import { Block } from "codechain-sdk/lib/core/Block";

async function main() {
  const sdk = new SDK({
    server: "https://corgi-rpc.codechain.io",
    networkId: "wc"
  });

  let currentBestBlockNumber = /* Fill this line */ 1;

  while (true) {
    const block: Block | null = /* Get block whose number is currentBestBlockNumber */ null;
    console.log(`New block ${currentBestBlockNumber} - ${block!.hash}`);

    await delay(100);

    let nextBlockNumber = /* Get current best block number */ 2;
    while (nextBlockNumber === currentBestBlockNumber) {
      await delay(1000);
      nextBlockNumber = /* Get current best block number */ 2;
    }

    currentBestBlockNumber = nextBlockNumber;
  }
}

main().catch(console.error);

async function delay(ms: number) {
  return new Promise(resolve => {
    setTimeout(() => {
      resolve();
    }, ms);
  });
}