Ethereum: Integrating ERC20 Approval Before Transaction using Wagmi on Frontend

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Ethereum: Integrating ERC20 Pre-Transaction Approval Using Wagmia in the Frontend

When building decentralized applications (dapps) on the Ethereum blockchain, one common challenge is handling token transfers between users. A key part of this process is ensuring that the user has approved the smart contract before transferring tokens.

In our dapps, we use ERC-20 tokens for a variety of purposes, including processing and storing payments. However, requiring users to approve a smart contract to transfer these tokens can be cumbersome and can lead to unnecessary delays or errors. This is where Wagmi comes in – a powerful and easy-to-use library that simplifies interaction with the Ethereum blockchain.

In this article, we will explore how to integrate ERC20 pre-transaction approval using Wagmia in our dapp frontend.

Why Wagmi?

Wagmi is a popular, modern Web3 library that provides a simple and intuitive way to interact with the Ethereum blockchain. Its core features include:

• Automatic token transfers: Wagmi handles the complex logic required for automatic token transfers, making it easier to focus on developing our dapp.

• Simple API calls

  : Wagmi’s API is designed to be easy to use, so developers can leverage its features without needing extensive knowledge of Ethereum programming.

• Error handling and retry mechanisms: Wagmi provides robust error handling and retry mechanisms to ensure that our application remains stable and efficient.

ERC20 Validation Integration with Wagmi

To integrate ERC20 validation before the transaction using Wagmi in our dapp’s UI, we follow these steps:

• Install Wagmi: First, install Wagmi by running “NPM Install Wagmi” or “Yarn Add Wagmi” in your project directory.

• Import Wagmi: To import Wagmi and its dependencies into our application:

import { useWagmi } 'wagmist';

• Create a provider: Next, we create an instance of the provider that will interact with the Ethereum blockchain:

const Provider = {
...useWagmi({
// Specify a provider chain (e.g. '
network: 'eth',
}),
};

• Define the token transfer function: Now we define a custom function to handle token transfers using Wagmi:

const handleTokenTransfer = async({data,params})=>{;
// Extract the ERC-20 token address and amount from the parameters
const tokenAddress = params.tokenAddress;
const amount = params . amount ;
// Use Wagmi to transfer tokens automatically
return await Provider . useMutation (
'transfer',
{
// Define the transaction details, including the token contract address, sender wallet address, and recipient wallet address
inputs: { from: params. fromAddress, to: tokenAddress, amount },
} }
);
};

• Call a custom function when a user tries to send tokens: We add a check to ensure that the user has approved the smart contract before transferring their tokens:

“` javascript

const handleTokenTransferRequest = async(event) => {

// Check if the user has approved the smart contract for token transfer

const result = await Provider.query({

query : {

inputs: {

fromAddress,

toAddress,

amount,

network: ‘eth’,

tx: { jsonrpc: ‘2.0’ },

},

},

});

// If approval is granted, continue token transfer with Wagm

if ( result . data . approval ) {

await handleTokenTransfer({ data: result.data, params: event });

} else {

// Handle the case where the user has not approved the smart contract

console.