Connect Wallet

At this point you should have an app rendering with a single "Connect Wallet" button. Try clicking on it and you should see a modal pop up with many wallets to choose from. Click "Keplr", approve the connection, and you should see the button shows your truncated address.

Accessing the Wallet Data

Now that we've connected to our wallet extension, there's some common tasks an app would want to do:

• Access the user's purse balances to see their tokens.
• Sign transactions in Keplr to make offers and interact with a smart contract.

The AgoricProvider makes both of these tasks straightforward. We'll focus on the first point in this section, and later on we'll see how to make an offer.

Create a Purses Component

Since the "Offer Up" contract uses IST as a fee token to purchase NFTs, we can start by showing the user's IST balance.

Create a new file, src/Purses.tsx, where you'll write a component for rendering purse balances.

import { useAgoric } from '@agoric/react-components';

const Purses = () => {
  const { walletConnection } = useAgoric();

  return (
    <div className="card">
      <h3>Purses</h3>
      {walletConnection ? (
        <div style={{ textAlign: 'left' }}>
          <div>
            <b>IST: </b>
            TODO - Render IST Balance
          </div>
        </div>
      ) : (
        'No wallet connected.'
      )}
    </div>
  );
};

export default Purses;

Then, in App.tsx render the component inside the AgoricProvider, below the <ConnectWalletButton />:

import Purses from './Purses';
...
    <ConnectWalletButton />
    <Purses />
...

Once the app rebuilds, you should see a "Purses" section. You'll notice that it uses the walletConnection object from the useAgoric hook. This is provided by the AgoricProvider, and right now the component just uses it to see if there is a wallet connection. If it still shows "No wallet connected." after connecting to Keplr, make sure that your local chain is running and check your console for any RPC errors.

Rendering the IST Balance

We'll access the purse data from the useAgoric hook. First, we'll create a new hook for convenience, since we'll need to render another purse for the NFTs later on. Create a new file, src/hooks.ts

import { useAgoric } from '@agoric/react-components';

export const usePurse = (brandPetname: string) => {
  const { purses } = useAgoric();

  return purses?.find(p => p.brandPetname === brandPetname);
};

This provides a utility for looking up a user's purse by name. Notice how it accesses purses from useAgoric(). The <AgoricProvider> handles all the chain queries to fetch the purses, and automatically polls and updates purses whenever the balances change. It also coalesces ERTP purses with VBank Assets and Cosmos Bank Balances automatically. See Smart Wallet VStorage Topics for more details about where this data comes from.

Next, we'll add a dependency on @agoric/web-components, which provides a utility for rendering amounts and handling various denoms:

yarn add -D @agoric/web-components@0.15.1-dev-1329752.0

Then, in Purses.tsx, we can put it all together to render the IST balance:

import { useAgoric } from '@agoric/react-components';
import { usePurse } from './hooks';
import { stringifyAmountValue } from '@agoric/web-components';

const Purses = () => {
  const { walletConnection } = useAgoric();
  const istPurse = usePurse('IST');

  return (
    <div className="card">
      <h3>Purses</h3>
      {walletConnection ? (
        <div style={{ textAlign: 'left' }}>
          <div>
            <b>IST: </b>
            {istPurse ? (
              stringifyAmountValue(
                istPurse.currentAmount,
                istPurse.displayInfo.assetKind,
                istPurse.displayInfo.decimalPlaces,
              )
            ) : (
              <i>Fetching balance...</i>
            )}
          </div>
        </div>
      ) : (
        'No wallet connected.'
      )}
    </div>
  );
};

When the app rebuilds, you should see the real IST balance appear below "Purses". Now you're able to connect to a user's wallet and render their purse balances, but what can you do from there? In the next section, you'll learn how to read smart contract data from the UI so the user can interact with it.

As usual, if you have any difficulties along the way, you can check out the checkpoint-3 branch in the example repo.