How can I tell which validator is being bonded to for a given bonding extrinsic?

Question

I would like to extract the validator that a given nominator is bonding? Is this possible given the extrinsic or should it be done some other way?

Here is my code:

const { ApiPromise, WsProvider } = require('@polkadot/api');

async function main() {
    // Initialise the provider to connect to the local node
    const provider = new WsProvider('wss://rpc.polkadot.io');

    // Create the API and wait until ready
    const api = await ApiPromise.create({ provider });

    const blockNumber = 11833484; 

    // returns Hash
    const blockHash = await api.rpc.chain.getBlockHash(blockNumber);
    // returns SignedBlock
    const signedBlock = await api.rpc.chain.getBlock(blockHash);

    const apiAt = await api.at(signedBlock.block.header.hash);
    const allRecords = await apiAt.query.system.events();


    const bondingEvents = allRecords.filter(ev => ev.event.method == 'Bonded');
    const bondingExtrinsics = bondingEvents
        .map(ev => 
            signedBlock.block.extrinsics.at(ev.phase.asApplyExtrinsic)
        );

    console.log(bondingExtrinsics[0].toHuman());
}


main().catch((error) => {
    console.error(error);
    process.exit(-1);
});

output:

{
  isSigned: true,
  method: {
    args: { max_additional: '13,428,193,000,000' },
    method: 'bondExtra',
    section: 'staking'
  },
  era: { MortalEra: { period: '64', phase: '7' } },
  nonce: '283',
  signature: '0x04aebb51e2b2b1947e3e344537caa45cad9caa170808d8ed2f448ef4e0433b69820e5f60b35065ed7c7adc0ecb88d03b9e1fdf46e6873b8f9263738dbc874080',
  signer: { Id: '15V25oBZGu7wAfV7LPP8YBwaWRgBAyfiVUtVywGHAcDAw9cD' },
  tip: '0'
}

The amount bonded and the account which is bonding are both clearly visible in the output. How, then, should I go about retrieving the validator which is being bonded to?

Answer 1

In this case, the user is not changing their nominations, but simply bonding more funds.

For this, you will need to query the nominations of the user, which can be done with something like:

let result = (await substrate.query.staking.nominators("15V25oBZGu7wAfV7LPP8YBwaWRgBAyfiVUtVywGHAcDAw9cD")).unwrap();

result.targets.toHuman()

[
  "13s9RrQSFbnp2TneY7nkdLmGc3ijBw12YQct8pc8km36Z9hg",
  "126RwaHn4MDekLWfUYfiqcVbiQHapwDSAT9vZZS15HLqfDJh",
  "15qomv8YFTpHrbiJKicP4oXfxRDyG4XEHZH7jdfJScnw2xnV",
  "123kFHVth2udmM79sn3RPQ81HukrQWCxA1vmTWkGHSvkR4k1",
  "167ShbHu769mP5jbtt7AHayJhzEied6s8M5kN5nBSAQewnRz",
  "13AxLFBLRACDWzjqEQn3YhHH2iErmyj3kC1HivYiSahkN2Fh",
  "131RTKxEkG6o1HZRRmETxj8ywpSsoF8KgoQp6twnMUf7W4Nu",
  "14aWupX88TM23UCmUTx69S9x9r7JNTLUZ4oprbdwy2s2xWyJ",
  "153RzmMmQ2ueHgD71nRcfcs96VKhFRPYkW2h1qw18Bn1Jkrv",
  "15dMdEYxCM9EWtbBdDf1vEvRV3se1tpvvxitFCURXV2jWArs",
  "1xzAes4aS1EK2hDBcuK3ZSrwvH4Hn4b5hs6aKrsoC8scLGK",
  "16aXLhFh9mZoyW5emqZM6fJWTqbWENGrJkAoGwtR1S8XoFwY",
  "13fj8s7NEamwDw2PmHVJ9acHApBMCLuRX2exbnovkxNa2fQV",
  "15ovsfcNsVc666r55fi4D6qiXpgP23ReRmPZL6Ss1THJ4rf2",
  "1KPeYhx2k2D4Fy7iw9CSykbTYN1UbtYxHpBceL85xQhAJdo",
  "16XwmL8Kh4fxXa4TyEAjaJRr1JLevnQsZ2GVF68ND9SqQWY4"
]