How to retrieve multiple contract properties in a single call?

Question

Let's take this contract as an example: 0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c.

It has multiple methods / properties that I wish to access, e.g.

function name() public view returns (string memory) {
    return _name;
}

function symbol() public view returns (string memory) {
    return _symbol;
}

function decimals() public view returns (uint8) {
    return _decimals;
}

function totalSupply() public view override returns (uint256) {
    return _tTotal;
}

At the moment, it seems like I need to call all of them individually, e.g.

await pairContract.methods.name().call()
await pairContract.methods.symbol().call()
await pairContract.methods.decimals().call()
await pairContract.methods.totalSupply().call()

Is there a way to retrieve all of the above in a single call to limit the number of roundtrips / requests?

I have found that there is BatchRequest, but from what I can tell, it is equivalent to:

[
  pairContract.methods.name().call(),
  pairContract.methods.symbol().call(),
  pairContract.methods.decimals().call(),
  pairContract.methods.totalSupply().call()
]

i.e. it does not actually batch the requests.

Answer 1

To answer my own question: Yes, you can, thanks to multicall smart contract and ethereum-bsc-multicall SDK.

It would look something like this:

const contractCallContext: ContractCallContext[] = [
  {
    abi: BEP20_ABI,
    calls: [
      {
        methodName: 'name',
        reference: 'name',
      },
      {
        methodName: 'symbol',
        reference: 'symbol',
      },
      {
        methodName: 'decimals',
        reference: 'decimals',
      },
      {
        methodName: 'totalSupply',
        reference: 'totalSupply',
      },
    ],
    contractAddress: '0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c',
    reference: 'summary',
  },
];

const findResultValue = (callsReturnContext, reference) => {
  return callsReturnContext.find((result) => {
    return result.reference === reference;
  })?.returnValues?.[0];
};

const response = await multicall.call(contractCallContext);

console.log({
  decimals: findResultValue(response.results.summary.callsReturnContext, 'decimals'),
  name: findResultValue(response.results.summary.callsReturnContext, 'name'),
  symbol: findResultValue(response.results.summary.callsReturnContext, 'symbol'),
  totalSupply: findResultValue(response.results.summary.callsReturnContext, 'totalSupply'),
});

which produces result such as:

{
  decimals: 18,
  name: 'Wrapped BNB',
  symbol: 'WBNB',
  totalSupply: { type: 'BigNumber', hex: '0x067463bb2aa7d7bc4ea935' }
}

Answer 2

If you are looking for an example in JS see https://github.com/indexed-finance/multicall.

const ethers = require('ethers');
const { MultiCall } = require('@indexed-finance/multicall');

async function getMultiCallResults(tokenAbi, provider){
  let tokenAddress = '0xbb4CdB9CBd36B01bD1cBaEBF2De08d9173bc095c';
  
  const multi = new MultiCall(provider);
  const callParams = [
      {target: tokenAddress, function: 'name', args: []},
      {target: tokenAddress, function: 'symbol', args: []}
      .......
  ];
  const tokenDatas = await multi.multiCall(tokenAbi, callParams);
  console.log(tokenDatas[1][0].toString()); // name
  console.log(tokenDatas[1][1].toString()); // symbol
  ......
}

Here you can find a full explanation of how multicall libraries work https://blockheroes.dev/same-block-data-querying/.