How to transfer an NFT

Question

I'm trying to transfer an NFT, that I just minted to someone without them paying for it (just like an exchange). Here is the function I created on smartpy:

@sp.entry_point
def transferTest(self, params):
        sp.verify(self.data.data[params.token_id].collectable, "NotCollectable")
        sp.verify(self.data.data[params.token_id].author != sp.sender, "SenderNotAuthor")
        self.data.data[params.token_id].collectable = True
        self.data.data[params.token_id].holder = sp.sender

The code in the test function:

marketplace.transferTest(token_id=1).run(sender=elon.address)

Here is the complete smart contract: https://legacy.smartpy.io/ide?cid=QmSGKqymMBSLHADF5GC9nzqSNikwuFYcT2ZUwjaTzsyxWP&k=893cdae17d61921e246b

On smartpy everything works fine, now when I want to call the function in React JS:

  export const transferTokens = ({ Tezos, id, to }) => {
    return async (dispatch) => {
      try {
        const contract = await Tezos.wallet.at(config.contractAddress);

        
        const operation = await contract.methods.transferTest(id)
        .send({ sender: to });

      await operation.confirmation();

        dispatch(fetchData());
      } catch (e) {
        console.log(e);
      }
    };
  };

I get this error:

{
"error":[
0:{
"errors":[...]
"errorDetails":"Error occurred during estimation"
"name":"TezosOperationError"
"id":"proto.016-PtMumbai.michelson_v1.scri..."
"kind":"temporary"
"message":"SenderNotAuthor"
"isError":true
}
1:{
"errors":[...]
"errorDetails":"Error occurred during estimation"
"name":"TezosOperationError"
"id":"proto.016-PtMumbai.michelson_v1.scri..."
"kind":"temporary"
"message":"SenderNotAuthor"
"isError":true
}
]
"contents":undefined
}

I hope you could help me! THANKS

Answer 1

I managed to do the manipulation, here is the code of the smartcontract:

@sp.entry_point
def transferTest(self, params):
        sp.verify(self.data.data[params.token_id].collectable, "NotCollectable")
        sp.verify(self.data.data[params.token_id].holder == sp.sender, "NotAuthor")
        self.data.data[params.token_id].holder = params.to

Test code:

 scenario.h1("Transfert Elon")
 marketplace.transferTest(token_id=1, to=mark.address).run(sender=elon)

And my code (ReactJS):

const transferOperation = await contract.methods.transferTest(senderAddress, tokenId)
      .send();
      
await transferOperation.confirmation();