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.

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