safe_smart_contract_signing_example.js

import Safe, { SigningMethod, buildContractSignature } from '@safe-global/protocol-kit'

const MESSAGE = {
  types: {
    EIP712Domain: [
      {
        name: 'name',
        type: 'string'
      },
      {
        name: 'version',
        type: 'string'
      },
      {
        name: 'chainId',
        type: 'uint256'
      },
      {
        name: 'verifyingContract',
        type: 'address'
      }
    ],
    Register: [
      {
        name: 'key',
        type: 'address'
      },
      {
        name: 'message',
        type: 'string'
      },
      {
        name: 'nonce',
        type: 'uint64'
      }
    ]
  },
  primaryType: 'Register',
  domain: {
    name: 'BSX Testnet',
    version: '1',
    chainId: Number(84532),
    verifyingContract: '0x6d6F70C0778C57664E32bA6b65b637cBc0C41F09'
  },
  message: {
    key: '0x6263F97AE4360c5E057e42b36ff8e0Ee554673e6',
    message:
      'Please sign in with your wallet to access bsx.exchange. You are signing in on 1722929625000000000. This message is exclusively signed with bsx.exchange for security.',
    nonce: '1722929625000000000'
  }
}

interface Config {
  RPC_URL: string
  OWNER1_PRIVATE_KEY: string
  OWNER2_PRIVATE_KEY: string
  SAFE_2_2_ADDRESS: string
}

const config: Config = {
  RPC_URL: 'https://sepolia.base.org',
  OWNER1_PRIVATE_KEY: 'b2772045811cf64a001aedbd4debf0a1787fbf507e1a284a4df9100a6374935d',
  OWNER2_PRIVATE_KEY: '05600ca16954938238344fe571b5ee0afd6dce28d4759efd2dfb1f1628483c9b',
  SAFE_2_2_ADDRESS: '0xF6CDA5B4432D66267941bA9eb1Bd3E285B3aE13e'
}

async function main() {
  let protocolKit = await Safe.init({
    provider: config.RPC_URL,
    safeAddress: config.SAFE_2_2_ADDRESS
  })

  // Create a new message object
  let messageSafe2_2 = protocolKit.createMessage(MESSAGE)

  // Connect OWNER1_ADDRESS
  protocolKit = await protocolKit.connect({
    signer: config.OWNER1_PRIVATE_KEY
  })

  // Sign the messageSafe2_2 with OWNER1_ADDRESS
  // After this, the messageSafe2_2 contains the signature from OWNER1_ADDRESS
  messageSafe2_2 = await protocolKit.signMessage(
    messageSafe2_2,
    SigningMethod.SAFE_SIGNATURE,
    config.SAFE_2_2_ADDRESS
  )

  // Connect OWNER2_ADDRESS
  protocolKit = await protocolKit.connect({
    signer: config.OWNER2_PRIVATE_KEY
  })

  // Sign the messageSafe2_2 with OWNER2_ADDRESS
  // After this, the messageSafe2_2 contains the signature from OWNER2_ADDRESS
  messageSafe2_2 = await protocolKit.signMessage(
    messageSafe2_2,
    SigningMethod.SAFE_SIGNATURE,
    config.SAFE_2_2_ADDRESS
  )

  // Build the contract signature of SAFE_2_2_ADDRESS
  const signatureSafe2_2 = await buildContractSignature(
    Array.from(messageSafe2_2.signatures.values()),
    config.SAFE_2_2_ADDRESS
  )

  // Add the signatureSafe2_2 to safeMessage
  // After this, the safeMessage contains the signature from OWNER_1_ADDRESS, OWNER_2_ADDRESS
  messageSafe2_2.addSignature(signatureSafe2_2)

  console.log('Signature: ', messageSafe2_2.encodedSignatures())
}

main()