Optimism (ETH)

Optimism is a layer 2 scaling solution for Ethereum, which is designed to enable fast, secure, and low-cost transactions. It is built on the Optimistic Ethereum (OΞ) protocol, which is an Ethereum Virtual Machine (EVM) compatible layer 2 scaling solution. Optimism is designed to be a general-purpose scaling solution, which means that it can be used to scale any Ethereum application, including DeFi, NFTs, and more.

This document is based on the EVMs (Ethereum Virtual Machine) and the Ethereum network.

Detect XDEFI Wallet with Ethereum Base Chain

To detect whether your browser is running XDEFI Wallet, you can use the following code:

if (
  (typeof window.ethereum !== "undefined" && window.ethereum?._XDEFI) ||
  window.xfi
) {
  console.log("XDEFI Wallet detected");
  // Your code here
}

Notice: window.ethereum is a standard Ethereum provider object, and window.ethereum._XDEFI is a property added by XDEFI Wallet. If window.ethereum is not available, you can also check window.xfi which is a global object added by XDEFI Wallet.

The XDEFI Wallet on Ethereum JavaScript provider API is specified by EIP-1193 and EIP-6963. Support window.ethereum only and removal window.web3

Connect/Disconnect to XDEFI Wallet

To connect to XDEFI Wallet (access the user's [blockchain - like Ethereum] account(s)), you can use the following code:

// Connect & get accounts
window.ethereum.request({method: 'eth_accounts'});
// Alias for connection
window.ethereum.request({method: 'eth_requestAccounts'});​
// Check if dapp connected
window.ethereum.isConnected();
// Check if the caller's current permissions
window.ethereum.request({method: 'wallet_getPermissions'});
// Check if request the given permissions
window.ethereum.request({method: 'wallet_requestPermissions'});

To disconnect from XDEFI Wallet, please use:

window.ethereum.disconnect();

Experience functions

When your account is connected to XDEFI Wallet, let's start experiencing more functions.

Get the current account

window.ethereum.request({ method: "eth_accounts" }).then((accounts) => {
  if (accounts.length > 0) {
    console.log("Current account:", accounts[0]);
    // Do something with the account
  } else {
    console.log("No account connected");
    // Do something else
  }
});

Above code will return Promise<Array[String]> with the current account address. If wallet can not be found, return [] instead of throw Error

Check wallet whether it is connected(exists) or not

window.ethereum
  .request({ method: "has_wallet", params: ["ethereum"] })
  .then(() => {
    // Wallet is connected
  })
  .catch((e) => {
    // Wallet not found (not exist)
  });

Above code will return Promise<Boolean> with the current account address. If wallet can not be found, return false instead of throw Error

Sign Transaction

// Example Sign Transactionconst
const signature = window.ethereum.request({
  method: 'eth_signTransaction',
  params: [
    "from": "string",
    "to": "string",
    "gas": "string",
    "gasPrice": "string",
    "value": "string",
    "data": "string",
    "nonce": "string"
  ]
});

Above code will return Promise<Signature | RPC: 2.0>

Transfer

window.ethereum.request({
  method: "eth_sendTransaction",
  params: [
    {
      from: "string",
      to: "string",
      gas: "string",
      gasPrice: "string",
      value: "string",
      data: "string",
      nonce: "string",
    },
  ],
});

Return Promise<String> with the transaction hash

Decrypt Message

window.ethereum
  .request({ method: "eth_decrypt", params: [encryptedMessage, accounts[0]] })
  .then((decryptedMessage) =>
    console.log("The decrypted message is:", decryptedMessage),
  )
  .catch((error) => console.log(error.message));

Above code will return Promise<String> with the decrypted message

Get Encryption Public Key

Return Promise<String> with the public key

let encryptionPublicKey;
window.ethereum
  .request({
    method: "eth_getEncryptionPublicKey",
    params: [accounts[0]], // You must have access to the specified account
  })
  .then((result) => {
    encryptionPublicKey = result;
  })
  .catch((error) => {
    if (error.code === 4001) {
      // EIP-1193 userRejectedRequest error
      console.log("Can't encrypt anything without the key.");
    } else {
      console.error(error);
    }
  });

Encrypt Message

const ethUtil = require('ethereumjs-util');
const encryptedMessage = ethUtil.bufferToHex(
  Buffer.from(
    JSON.stringify(
      sigUtil.encrypt(
        {
          publicKey: encryptionPublicKey,
          data: 'Hello, World!,
          version: 'x25519-xsalsa20-poly1305',
        }
      )
    ),
    'utf8'
  )
);

Add Ethereum Chain

window.ethereum.request
interface AddEthereumChainParameter {
  chainId: string; // A 0x-prefix hex string
  chainName: string;
  nativeCurrency: {
    name: string;
    symbol: string; // 2-6 characters long
    decimals: 18;
  };
  rpcUrls: string[];
  blockExplorerUrls?: string[];
  iconUrls?: string[]; // Currently ignored
}

Return Promise<void> with the result

Switch Ethereum Chain

Return Promise<void> with the result, and an error otherwise

try {
  await window.await ethereum.request({
  method: 'wallet_switchEthereumChain',
    params: [{ chainId: '0xf00' }],
  });
} catch (switchError) {
  if (switchError.code === 4902) {
    try {
      await ethereum.request({
        method: 'wallet_addEthereumChain',
        params: [
          {
            chainId: '0xf00',
            chainName: '...',
            rpcUrls: ['https://...'] /* ... */,
          },
        ],
      });
    } catch (addError) {
      // handle "add" error
    }
  }
  // handle other "switch" errors
}

Watch Asset

Return true if the token was added, false otherwise

window.ethereum
  .request({
    method: "wallet_watchAsset",
    params: {
      type: "ERC20",
      options: {
        address: "0x1234567890123456789012345678901234567890",
        symbol: "FOO",
        decimals: 18,
        image: "https://example.com/token-image.png",
      },
    },
  })
  .then((success) => {
    if (success) {
      console.log("FOO successfully added to wallet!");
    } else {
      throw new Error("Something went wrong.");
    }
  })
  .catch(console.error);

RPC Request

Return Promise<Ethereum RPC> Currently only support HTTP(s) method Reference: RPC Method

window.ethereum.request({method: '<Method>', params: [args1,....]})

Subscription

Support subscribe using JSON-RPC notifications. This allows clients to wait for events instead of polling for them. All results will be released at data event.

Methods

// For Subscribe
window.ethereum
  .request({
    method: "eth_subscribe",
    params: ["<type>", "<options>"],
  })
  .then((subscriptionId) => {
    console.log("Subscription ID:", subscriptionId);
    // Do something with the subscription ID
  });

// For Unsubscribe
window.ethereum.request({
  method: "eth_unsubscribe",
  params: ["<Subscription ID>"],
});

Example

// Subscribe for event
const subscriptionID = window.ethereum.request({method: 'eth_subscribe', params: ["logs", {
  address: "0x1234567890123456789012345678901234567890",
  topics: ["0x1234567890123456789012345678901234567890123456789012345678901234"]
})
// You can listen for incoming notifications by
window.ethereum.on("data", data => {
  // Do the rest of your work with data
})

Events

Currently we only support some action events from Wallet

window.ethereum.on('event_name', callback);
​//Example
window.ethereum.on('close', () => window.location.reload());
window.ethereum.on('accountsChanged', () => window.location.reload());

Events supported

Events	Trigger
accountsChanged	Receive when active account changed in Wallet
networkChanged	Receive when active network changed in Wallet
chainChanged	Receive when active chain changed in Wallet
close	Alias for disconnect event
disconnect	Receive when disconnecting from Wallet

Methods supported

Methods	Description
on(event, callback)	Add event listener
off(event, callback)	Remove event listener