ethcall
Utility library to make calls to Ethereum blockchain.
Uses MakerDAO's Multicall contracts to make multiple requests in a single HTTP query. Encodes and decodes data automatically.
Powered by abi-coder and ethers.js.
npm install ethcall
API
Contract
constructor(address, abi)
: creates Contract instanceCALL_FUNC_NAME
: yields a call
object; usage is similar to ethers
Contract class
Provider
constructor()
: creates Provider instanceinit(ethersProvider)
: initializes a provider; should be called once before any other requestall(calls)
: executes all calls in a single requesttryAll(calls)
: executes all calls in a single request. Ignores reverted calls and returns null
value in place of return data (wrapper on top of tryAggregate
method)tryEach(calls, canFail)
: executes all calls in a single request. Ignores reverted calls and returns null
value in place of return data for the calls that are allowed to fail (wrapper on top of aggregate3
method)getEthBalance(address)
: returns account ether balance
Example
Also see examples for reference.
import { InfuraProvider } from '@ethersproject/providers';
import { Contract, Provider } from 'ethcall';
import erc20Abi from './abi/erc20.json';
const infuraKey = 'INSERT_YOUR_KEY_HERE';
const provider = new InfuraProvider('mainnet', infuraKey);
const daiAddress = '0x6b175474e89094c44da98b954eedeac495271d0f';
async function call() {
const ethcallProvider = new Provider();
await ethcallProvider.init(provider);
const daiContract = new Contract(daiAddress, erc20Abi);
const uniswapDaiPool = '0x2a1530c4c41db0b0b2bb646cb5eb1a67b7158667';
const ethBalanceCall = ethcallProvider.getEthBalance(uniswapDaiPool);
const daiBalanceCall = daiContract.balanceOf(uniswapDaiPool);
const data = await ethcallProvider.all([ethBalanceCall, daiBalanceCall]);
const ethBalance = data[0];
const daiBalance = data[1];
console.log('eth balance', ethBalance.toString());
console.log('dai balance', daiBalance.toString());
}
call();
Contributing
All Mulitcall contracts are stored in src/multicall.ts
file. There are three getMulticall
methods corresponding to three Multicall versions. To add a new contract, you need to know its version, address, chain id of the underlying chain, and (optionally) block at which the Multicall contract was deployed.
Deployless Multicall
If you query a chain on which Multicall is not deployed, or if you query a historical block before the deployment of the contract, the deployless version will be used instead. In short, deployless Multicall "emulates" the deployed contract and returns the exact same data. Note that you can't query ETH balance using deployless version.
You can read more about deployless Multicall here.