Can't sign data with Nami Wallet

Question

I'm facing a problem when I try to sign data with Nami Wallet API.

Here is the code snippet:

let namiAPI = await window.cardano.nami.enable();
let addr = await namiAPI.getUsedAddresses();
let payload = "48656C6C6F20576F726C6421"; //hex of "Hello World!"
let signed = await namiAPI.signData(addr.get(0), payload);

I get the following error:

{
    "code": 4,
    "info": "If a wallet enforces data format requirements, this error signifies that the data did not conform to valid formats."
}

What could be the problem? Am I encoding the payload wrong?

Answer 1

That payload looks good, just the address seems invalid. Probably need to access the array via addr[0] instead of addr.get(0), try this:

let namiAPI = await window.cardano.nami.enable();
let addr = await namiAPI.getUsedAddresses();
let payload = "48656C6C6F20576F726C6421"; //hex of "Hello World!"
let signed = await namiAPI.signData(addr[0], payload);