eth_syncing - zkSync RPC Method

curl -X POST https://api-zksync-era-mainnet-full.n.dwellir.com/YOUR_API_KEY \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "method": "eth_syncing",
    "params": [],
    "id": 1
  }'

import { JsonRpcProvider } from 'ethers';

const provider = new JsonRpcProvider('https://api-zksync-era-mainnet-full.n.dwellir.com/YOUR_API_KEY');

const syncing = await provider.send('eth_syncing', []);
if (syncing === false) {
  console.log('Node is fully synced');
} else {
  console.log('Syncing:', syncing);
}