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viem

Viem is currently only available on Base Sepolia testnet.

viem a TypeScript interface for Ethereum that provides low-level stateless primitives for interacting with Ethereum.

You can use viem to interact with smart contracts deployed on Base.

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Install

To install viem run the following command:

npm install --save viem

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Setup

Before you can start using viem, you need to setup a Client with a desired Transport and Chain.

import { createPublicClient, http } from 'viem';
import { base } from 'viem/chains';

const client = createPublicClient({
  chain: base,
  transport: http(),
});

To use Base, you must specify base as the chain when creating a Client.

To use Base Sepolia (testnet), replace base with baseSepolia.

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Reading data from the blockchain

Once you have created a client, you can use it to read and access data from Base using Public Actions

Public Actions are client methods that map one-to-one with a “public” Ethereum RPC method (eth_blockNumber, eth_getBalance, etc.)

For example, you can use the getBlockNumber client method to get the latest block:

const blockNumber = await client.getBlockNumber();

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Writing data to the blockchain

In order to write data to Base, you need to create a Wallet client (createWalletClient) and specify an Account to use.

import { createWalletClient, custom } from 'viem'
import { base } from 'viem/chains'

//highlight-start
const [account] = await window.ethereum.request({ method: 'eth_requestAccounts' })
//highlight-end

const client = createWalletClient({
  //highlight-next-line
  account,
  chain: base,
  transport: custom(window.ethereum)
})

client.sendTransaction({ ... })

In addition to making a JSON-RPC request (eth_requestAccounts) to get an Account, viem provides various helper methods for creating an Account, including: privateKeyToAccount, mnemonicToAccount, and hdKeyToAccount.

To use Base Sepolia (testnet), replace base with baseSepolia.

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Interacting with smart contracts

You can use viem to interact with a smart contract on Base by creating a Contract instance using getContract and passing it the contract ABI, contract address, and Public and/or Wallet Client:

import { getContract } from 'viem';
import { wagmiAbi } from './abi';
import { publicClient } from './client';

// 1. Create contract instance
const contract = getContract({
  address: 'CONTRACT_ADDRESS',
  abi: wagmiAbi,
  publicClient,
});

// 2. Call contract methods, listen to events, etc.
const result = await contract.read.totalSupply();

CONTRACT_ADDRESS is the address of the deployed contract.