4. Submit Data to Chain

In the fourth chapter of the tutorial on building an end-to-end dapp on Aptos, you will be submitting data to the chain.

So now we have an Add new list button that appears if the connected account hasn’t created a list yet. We still don’t have a way for an account to create a list, so let’s add that functionality.

1. First, our wallet adapter provider has a signAndSubmitTransaction function; let’s extract it by updating the following:

const { account, signAndSubmitTransaction } = useWallet();

2. Add an onClick event to the new list button:

<Button
  onClick={addNewList}
>
  Add new list
</Button>

3. Update the import statement from @aptos-labs/wallet-adapter-react to also import the InputTransactionData type and

import {
  useWallet,
  InputTransactionData,
} from "@aptos-labs/wallet-adapter-react";

4. Add the addNewList function:

const addNewList = async () => {
  if (!account) return [];

   const transaction:InputTransactionData = {
      data: {
        function:`${moduleAddress}::todolist::create_list`,
        functionArguments:[]
      }
    }
  try {
    // sign and submit transaction to chain
    const response = await signAndSubmitTransaction(transaction);
    // wait for transaction
    await aptosClient().waitForTransaction({transactionHash:response.hash});
    setAccountHasList(true);
  } catch (error: any) {
    setAccountHasList(false);
  }
};

5. Since our new function also uses moduleAddress, let’s get it out of the fetchList function scope to the global scope so it can be used globally.

In our fetchList function, find the line:

const moduleAddress = MODULE_ADDRESS;

And move it to outside of the main App function, so it can be globally accessed.

Let’s go over the addNewList function code.

First, we use the account property from our wallet provider to make sure there is an account connected to our app.

Then we build our transaction data to be submitted to chain:

const transaction:InputTransactionData = {
      data: {
        function:`${moduleAddress}::todolist::create_list`,
        functionArguments:[]
      }
    }

• function- is built from the module address, module name and the function name.
• functionArguments - the arguments the function expects, in our case it doesn’t expect any arguments.

Next, we submit the transaction payload and wait for its response. The response returned from the signAndSubmitTransaction function holds the transaction hash. Since it can take a bit for the transaction to be fully executed on chain and we also want to make sure it is executed successfully, we waitForTransaction. And only then we can set our local accountHasList state to true.

6. Before testing our app, let’s tweak our UI a bit and add a Spinner component to show up while we are waiting for the transaction. Add a local state to keep track whether a transaction is in progress:

const [transactionInProgress, setTransactionInProgress] =
  useState<boolean>(false);

7. Update our addNewList function to update the local state:

const addNewList = async () => {
  if (!account) return [];
  setTransactionInProgress(true);
  const transaction:InputTransactionData = {
      data: {
        function:`${moduleAddress}::todolist::create_list`,
        functionArguments:[]
      }
    }
  try {
    // sign and submit transaction to chain
    const response = await signAndSubmitTransaction(transaction);
    // wait for transaction
    await aptosClient().waitForTransaction({transactionHash:response.hash});
    setAccountHasList(true);
  } catch (error: any) {
    setAccountHasList(false);
  } finally {
    setTransactionInProgress(false);
  }
};

9. Update our UI with the following:

return (
  <>
    ...
      {!accountHasList && (
        <div className="flex items-center justify-center flex-col">
          <Button onClick={addNewList} disabled={transactionInProgress}>
            Add new list
          </Button>
        </div>
      )}
  </>
);

Now you can head over to our app, and add a new list!

Since you haven’t made the user interface able to handle cases where an account has created a list, you will do so next handling tasks in chapter 5.