Sign Typed Data

Calling signTypedData

Once you have built an ethereum typed data, you can ask the user to sign it by using signTypedData function in MetaKeep SDK. The function expects a non-empty reason which is shown to the user at the time of typed data signing.

This API is compliant with the latest EIP-712 spec and is a drop in replacement for Metamask's signTypedData_v4 API.

await sdk.signTypedData(
    // Typed data
    {
        types: {
            EIP712Domain: [{
                    name: "name",
                    type: "string"
                },
                {
                    name: "version",
                    type: "string"
                },
                {
                    name: "chainId",
                    type: "uint256"
                },
                {
                    name: "verifyingContract",
                    type: "address"
                },
            ],
            MetaTransaction: [{
                    name: "nonce",
                    type: "uint256",
                },
                {
                    name: "from",
                    type: "address",
                },
                {
                    name: "functionSignature",
                    type: "bytes",
                },
            ],
        },
        primaryType: "MetaTransaction",
        domain: {
            name: "Ether Mail",
            version: "1",
            chainId: 1,
            verifyingContract: "0xCcCCccccCCCCcCCCCCCcCcCccCcCCCcCcccccccC",
        },
        message: {
            nonce: 200,
            from: "0x97706Df14A769E28EC897dAc5Ba7bCfa5AA9C444",
            functionSignature: "0xd1a1beb40000",
        },
    },
    // signing reason
    "reason",
);

Here's a reference implementation of this code: https://jsfiddle.net/passbird/j8egh6fr/

Response

signTypedData returns a promise which succeeds when the sign operation is successful. The response looks like this-

{
  status: "SUCCESS",
  // Signature of the signed typed data. The signature encodes the r, s and v parameters 
  // from appendix F of the yellow paper in big-endian format. 
  // Bytes 0…32 contain the r parameter, bytes 32…64 the s parameter and the last byte the v parameter.
  signature: "0x1a84678f385553358386051464a252fa25d019335deb20262eb231d4ec1467300e6f1944e872430b7e04af6dd68ece90e2a9995a7abd827b50588602523b525600",
  r: "0x1a84678f385553358386051464a252fa25d019335deb20262eb231d4ec146730",
  s: "0x0e6f1944e872430b7e04af6dd68ece90e2a9995a7abd827b50588602523b5256",
  v: "0x0"
}

Error status

signTypedData returns a promise which throws an error when the sign operation is unsuccessful. The error object looks like so-

{
  status: "USER_CONSENT_DENIED"
}

Here's a table of all possible error status returned by the SDK

Status	Description
USER_REQUEST_DENIED	User has denied the sign operation. In this case, you should ask the user if they want to try again.
INVALID_REQUEST	Invalid data passed to sign operation. Please get in touch with us if you are unable to fix this.
APP_ID_REQUIRED	No app id provided when initializing the SDK. You can find the app id in MetaKeep Developer Console.
APP_NOT_FOUND	Provided app id is invalid. You can find the correct app id in MetaKeep Developer Console.
SOMETHING_WENT_WRONG	Unknown error happened. Please get in touch with us if you continue seeing this error.