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Compose allows you to interact with smart contracts with type safety and flexible wallet options. See wallets for details on the different types of wallets. We also have some built-in contract support for common interfaces like erc20.

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Code Gen

In order to interact with smart contracts, you put your ABI files into a “/contracts” folder. Then when you run goldsky compose codegen, we’ll generate typed contract classes that you can use like so: 
/// <reference types="../../.compose/types.d.ts" /> 

// access the class you generated in the steps above
import { BitcoinOracleContract } from "../.compose/generated";

export async function main(
  { evm, env }: TaskContext,
  _args: any
) {
  const wallet = await env.wallet();

  const response = await fetch<{ bitcoin: { usd: number } }>(
    "https://api.coingecko.com/api/v3/simple/price?ids=bitcoin&vs_currencies=usd"
  );

  // Convert timestamp and price to bytes32 format
  const timestampAsBytes32 = `0x${timestamp.toString(16).padStart(64, '0')}`;
  const priceAsBytes32 = `0x${Math.round(bitcoinPrice * 100).toString(16).padStart(64, '0')}`;

  const bitcoinOracleContract = new BitcoinOracleContract(env.ORACLE_ADDRESS, evm.chains.base, wallet);

  // execute the "write" method
  await bitcoinOracleContract.write.write(
    timestampAsBytes32, 
    priceAsBytes32,
    { 
      confirmations: 3, // this will not resolve the promise until the transaction has been seen in 3 blocks
      onReorg: {
        // this will replay the transaction with new nonce and new gas if it's reorged later on after the three confirmations have passed
        // see "Reorg Handling" for more info
        type: "replay", 
      }
    }
  );

  // simulate the "write" method
  await bitcoinOracleContract.write.simulate(
    timestampAsBytes32, 
    priceAsBytes32
  );

  // read a "getLatestPrice" view method
  const { price, time } = await bitcoinOracleContract.getLatestPrice.read();
}

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Wallet Methods

You can also interact with contracts without generating an instance of a contract class or having to obtain a full ABI. If you know the address and signature of the smart contract method, then you can call it directly with your wallet. Read more here. 
/// <reference types="../../.compose/types.d.ts" /> 

export async function main(
  { evm, env }: TaskContext,
  _args: any
) {
  const wallet = await evm.wallet();

  const { hash } = await wallet.writeContract(
    evm.chains.polygon,
    env.CONTRACT_ADDRESS,
    "reportPayouts(bytes32,uint256[])",
    [resultId, payouts],
  );
}