let walletProvider, walletSigner;
​
//networkProvider as defined above for ethers can be used for sendTransaction (send raw transaxction) or waitForTransaction for special cases (i.e. backend private key etc)  
​
// Initialize Constants
const domainType = [
    { name: "name", type: "string" },
    { name: "version", type: "string" },
    { name: "verifyingContract", type: "address" },
    { name: "salt", type: "bytes32" },
];
const metaTransactionType = [
    { name: "nonce", type: "uint256" },
    { name: "from", type: "address" },
    { name: "functionSignature", type: "bytes" }
];
// replace the chainId 42 if network is not kovan
let domainData = {
    name: "TestContract",
    version: "1",
    verifyingContract: config.contract.address,
    // converts Number to bytes32. Use your own chainId instead of 42 for other networks
    salt: ethers.utils.hexZeroPad((ethers.BigNumber.from(42)).toHexString(), 32)
};
​
​
let contract = new ethers.Contract(<CONTRACT_ADDRESS>,
              <CONTRACT_ABI>, biconomy.getSignerByAddress(userAddress));
let contractInterface = new ethers.utils.Interface(<CONTRACT_ABI>);
​
 /*
  This provider is linked to your wallet.
  If needed, substitute your wallet solution in place of window.ethereum 
 */
walletProvider = new ethers.providers.Web3Provider(window.ethereum);
walletSigner = walletProvider.getSigner();
​
let nonce = await contract.getNonce(userAddress);
let functionSignature = contractInterface.encodeFunctionData("setQuote", [newQuote]);
                
let message = {};
message.nonce = parseInt(nonce);
message.from = userAddress;
message.functionSignature = functionSignature;
​
const dataToSign = JSON.stringify({
  types: {
    EIP712Domain: domainType,
    MetaTransaction: metaTransactionType
  },
  domain: domainData,
  primaryType: "MetaTransaction",
  message: message
});
​
/*Its important to use eth_signTypedData_v3 and not v4 to get EIP712 signature 
because we have used salt in domain data instead of chainId*/
// Get the EIP-712 Signature and send the transaction
let signature = await walletProvider.send("eth_signTypedData_v3", [userAddress, dataToSign])
let { r, s, v } = getSignatureParameters(signature);
let tx = contract.executeMetaTransaction(userAddress,
             functionSignature, r, s, v);
             
await tx.wait(1);
console.log("Transaction hash : ", tx.hash); 
             
             
//////////
/*helper*/
​
const getSignatureParameters = signature => {
        if (!ethers.utils.isHexString(signature)) {
            throw new Error(
                'Given value "'.concat(signature, '" is not a valid hex string.')
            );
        }
        var r = signature.slice(0, 66);
        var s = "0x".concat(signature.slice(66, 130));
        var v = "0x".concat(signature.slice(130, 132));
        v = ethers.BigNumber.from(v).toNumber();
        if (![27, 28].includes(v)) v += 27;
        return {
            r: r,
            s: s,
            v: v
        };
    };