Simplistic Context provider and consumer hook in order to manage MetaMask in the browser.
The recommend way to use MetaMask React with a React app is to install it as a dependency.
If you use npm
:
npm install metamask-connetor-ts
Or if you use yarn
:
yarn add metamask-connetor-ts
The first step is to wrap you App
or any React subtree with the MetaMaskProvider
// index.js
import { MetaMaskProvider } from "metamask-connetor-ts";
...
ReactDOM.render(
<React.StrictMode>
<MetaMaskProvider>
<App />
</MetaMaskProvider>
</React.StrictMode>,
document.getElementById('root')
);
In any React child of the provider, one can use the useMetaMask
hook in order to access the state and methods.
// app.js
import { useMetaMask, Status } from "metamask-connetor-ts";
...
function App() {
const { status, connect, account, chainId, ethereum } = useMetaMask();
if (status === Status.INITIALIZING) return <div>Synchronisation with MetaMask ongoing...</div>
if (status === Status.UNAVAILABLE) return <div>MetaMask not available :(</div>
if (status === Status.NOT_CONNECTED) return <button onClick={connect}>Connect to MetaMask</button>
if (status === Status.CONNECTING) return <div>Connecting...</div>
if (status === Status.CONNECTED) return <div>Connected account {account} on chain ID {chainId}</div>
return null;
}
The MetaMaskProvider
will first initialise the state with initializing
status, the account
and chainId
will be null
. A synchronization is performed in order to derive the MetaMask state.
If the ethereum
object is not present or if it is not the one associated to MetaMask, the synchronisation will change the status to unavailable
.
Otherwise, a check is performed in order to detect if MetaMask has already connected accounts for the application.
In case of no connected accounts, the status will be notConnected
, otherwise the status will be connected
.
Here is an abstract on the different statuses:
-
initializing
: the provider is currently initializing by synchronizing with MetaMask -
unavailable
: MetaMask is not available, nothing will be done -
notConnected
: MetaMask is available but not connected to the application -
connected
: MetaMask is connected to the application -
connecting
: the connection of your accounts to the application is ongoing
The context exposes two methods in order to facilitate the management of the networks. These methods are wrappers around the JSON RPC requests handled by MetaMask, see MetaMask documentation for additonal informations.
Request a switch to a different network
function WrongNetwork() {
const { switchChain } = useMetaMask();
// Request a switch to Ethereum Mainnet
return (
<button onClick={() => switchChain("0x1")}>Switch to Ethereum Mainnet</button>
)
}
Request to add to MetaMask a network and then connect to it
function WrongNetwork() {
const { addChain } = useMetaMask();
const gnosisChainNetworkParams = {
chainId: "0x64",
chainName: "Gnosis Chain",
rpcUrls: ["https://rpc.gnosischain.com/"],
nativeCurrency: {
name: "xDAI",
symbol: "xDAI",
decimals: 18,
},
blockExplorerUrls: ["https://blockscout.com/xdai/mainnet/"]
};
// Request to add Gnosis chain and then switch to it
return (
<button onClick={() => addChain(gnosisChainNetworkParams)}>Add Gnosis chain</button>
)
}
Call metamask to sign a transaction
function TransferHandler() {
const { transfer, getSigner } = useMetaMask();
const handleTransfer = async () => {
const signer = await getSigner()
const contract = new ethers.Contract(
'0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
TOKEN_ABI,
signer
)
const decimals = await contract.decimals()
const tx = {
to: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
value: 0,
data: contract.interface.encodeFunctionData('transfer', [
'0x479A641d2d037a46fb68d9d0d0Ac8183d911c8B1',
utils.parseUnits('500', decimals)
]),
gasLimit: 100000
}
await signer.sendTransaction(tx)
}
return (
<button onClick={handleTransfer}>Handle Tranfer</button>
)
}
Call metamask to send a transfer
function TransferHandler() {
const { transfer } = useMetaMask();
const onTransfer = async () => {
const tx = {
to: '0x479A641d2d037a46fb68d9d0d0Ac8183d911c8B1',
value: utils.parseEther('1')
}
const txResponse = await transfer(tx)
console.log(txResponse.hash)
}
return (
<button onClick={onTransfer}>Call a Transfer</button>
)
}
Call metamask to invoke the contract method
function ContractMethodHandler() {
const { callContractMethod } = useMetaMask();
const call = async () => {
callContractMethod({
contractAddress: '0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48',
methodName: 'transfer',
params: [],
abi: []
})
}
return (
<button onClick={call}>Call Contract Method</button>
)
}
Finally, here is a non exhaustive list of the networks and their chain IDs
const networks = {
mainnet: "0x1", // 1
// Test nets
goerli: "0x5", // 5
ropsten: "0x3", // 3
rinkeby: "0x4", // 4
kovan: "0x2a", // 42
mumbai: "0x13881", // 80001
// Layers 2
arbitrum: "0xa4b1", // 42161
optimism: "0xa", // 10
// Side chains
polygon: "0x89", // 137
gnosisChain: "0x64", // 100
// Alt layer 1
binanceSmartChain: "0x38", // 56
avalanche: "0xa86a", // 43114
cronos: "0x19", // 25
fantom: "0xfa" // 250
}
Most of the time, the application will use the state when the user is connected, i.e. with status connected
. Therefore the hook useConnectedMetaMask
is additionally exposed, it is the same hook as useMetaMask
but is typed with the connected state, e.g. the account
or the chainId
are necessarily not null
. This hook is only usable when the status is equal to connected
, it will throw otherwise.
function MyComponent() {
const {
// typed as string - can not be null
account,
// typed as string - can not be null
chainId
} = useConnectedMetaMask();
return <div>Connected account {account} on chain ID {chainId}</div>
}
This project is based on the metamask-react, which provides a solid foundation for our work. We would like to express our sincere gratitude to the contributors and maintainers of the original project for their hard work and dedication.
We originally started our development work on the metamask-react, but soon realized that some aspects of the original repository didn't align with our needs. Despite submitting pull requests and opening issues to address these concerns, we weren't able to reach a resolution with the project maintainers. As a result, we decided to fork the original repository and create this new project. This allows us to make the necessary modifications to the codebase and tailor it to our specific use case, while still benefiting from the ongoing improvements and bug fixes in the upstream repository. We understand that forking a repository can be seen as a last resort, and we want to emphasize that we made every effort to work with the original project before taking this step. Ultimately, we believe that this was the best course of action to ensure that our project meets the needs of our users and stakeholders.