sign_EIP712.js

/**
 *
 * @param {ethers.Wallet} wallet
 * @param {ethers.BigNumber} chainId
 * @param {string} verifyingContract
 * @returns {string} full signature
 * 
 * rewards is an object: {
            id: ethers.BigNumber,
            amount: ethers.BigNumber,
            tokenContract: string,
            recipient: string,
            timestamp: ethers.BigNumber
 *   }
 */
async function signEIP712(wallet, chainId, verifyingContract, rewards) {
    const domain = {
        name: 'Rewards',
        version: '1',
        chainId,
        verifyingContract,
    };

    // The named list of all type definitions
    const types = {
        Rewards: [
            { name: 'id', type: 'uint256' },
            { name: 'amount', type: 'uint256' },
            { name: 'tokenContract', type: 'address' },
            { name: 'recipient', type: 'address' },
            { name: 'timestamp', type: 'uint256' },
        ],
    };

    return await wallet._signTypedData(domain, types, { ...rewards });
}

module.exports = {
    signEIP712,
};





------------------ FOUNDRY mock up ------------------ 

// // SPDX-License-Identifier: UNLICENSED
// pragma solidity ^0.8.13;

// import {Strings} from "openzeppelin-contracts/utils/Strings.sol";

// import {SetUpRewards, MockRewards} from "./SetUpRewards.sol";

// contract RewardsTest_claimRewards is SetUpRewards {
//     function test_signature_SolidityVsJS() public {
//         (uint8 _v, bytes32 _r, bytes32 _s) = vm.sign(
//             privateKey,
//             rewards.hashReward_EIP712Format(erc20Rewards)
//         );
//         bytes memory soliditySignature = abi.encodePacked(_r, _s, _v);

//         bytes memory jsSignature = __signJs(
//             Strings.toHexString(uint160(address(rewards)), 20)
//         );

//         assertEq(soliditySignature, jsSignature);
//     }

//     function __signJs(string memory rewardsContractAddr)
//         private
//         returns (bytes memory)
//     {
//         string[] memory cmd = new string[](3);
//         cmd[0] = "node";
//         cmd[1] = "test/utils/test_ethersEIP712.js";
//         cmd[2] = rewardsContractAddr;
//         return vm.ffi(cmd);
//     }
// }