To get block information call get_block on the rpc object passing in the block number as a required argument.
(async () => {
await rpc.get_block(1) //get the first block
})();The block data is returned as JSON.
{
"timestamp": "2018-06-01T12:00:00.000",
"producer": "",
"confirmed": 1,
"previous": "0000000000000000000000000000000000000000000000000000000000000000",
"transaction_mroot": "0000000000000000000000000000000000000000000000000000000000000000",
"action_mroot": "cf057bbfb72640471fd910bcb67639c22df9f92470936cddc1ade0e2f2e7dc4f",
"schedule_version": 0,
"new_producers": null,
"header_extensions": [],
"producer_signature": "SIG_K1_111111111111111111111111111111111111111111111111111111111111111116uk5ne",
"transactions": [],
"block_extensions": [],
"id": "00000001bcf2f448225d099685f14da76803028926af04d2607eafcf609c265c",
"block_num": 1,
"ref_block_prefix": 2517196066
}