Here is an article that explains the issue you’re facing with Metamask’s function selector not found error when calling a smart contract from your ReactJS application:

Metamask Function Selector Not Found Error

When developing decentralized applications (dApps), it is common to interact with Ethereum-based contracts using Web3 libraries such as Ethers.js. However, one common issue that can arise is the “function selector not found” error in Hardhat node.

In this article, we’ll delve into what causes this error and how you can resolve it when calling a smart contract from your ReactJS application using Metamask.

What is Metamask?

Metamask is an Ethereum wallet that allows users to interact with the Ethereum blockchain. It provides a user-friendly interface for managing private keys, sending transactions, and accessing various functionality of the Ethereum network.

Function Selector Not Found Error in Hard Node

When using Hardhat Node to compile and deploy smart contracts, Metamask needs to know which function selector to use to interact with the contract. However, if this information is not provided or is incorrect, you will encounter a “function selector not found” error.

Here’s an example of what might go wrong:

import { compile } from ' hard - typescript ' ;


const compileContract = async(contractName, ABI) => {

  try {

    const contract = await compile(contractName);

    const binascii = Buffer.from(ABI.map((key) => key.type).join(','));

    const selector = '0x' + binascii;

    console.log(selector); // This should be the correct function selector


    // Now, you're calling the contract with this selector

    await contract.at(selector).call('getTokenDepositAmount', inputToken);

  } catch (error) {

    console.error(error);

  } }

};

In this example, selector is a hexadecimal string that represents the Ethereum bytecode for the function getTokenDepositAmount. The at() method of the contract object returns a new contract with the specified selector. However, if you are using a smart contract from Metamask’s collection, such as the “SushiSwap” contract, it will have a different bytecode.

What goes wrong when using Metamask?

There are several reasons why you might encounter a “function selector not found” error:

• Incorrect ABI

  : If your smart contract’s ABI is incorrect or missing certain functions, Metamask will not be able to determine the correct function selector.

• Metamask collection

  : When using a smart contract from Metamask’s collection (e.g., SushiSwap), you need to specify the correct bytecode in the compileContract function.

• Hardhat configuration: Your Hardhat project may not have the necessary configuration settings or dependencies to properly compile and deploy your smart contracts.

Resolving the issue

To resolve this error, ensure that:

• You’ve correctly compiled and deployed your smart contract using a tool like Truffle or Vyper.

• Your Metamask collection is set up correctly and includes all required functions (e.g., getTokenDepositAmount).

• Your Hardhat project has the necessary dependencies and configuration settings.

Here’s an updated example that uses SushiSwap’s contract:

“`javascript

import { compileContract } from ‘ hard – typescript ‘ ;

import ‘@nomiclabs/hardhat-waffle’;

const compile = async(contractName, ABI) => {

try {

const contract = await compile(contractName);

const binascii = Buffer.from(ABI.map((key) => key.type).join(‘,’));

const selector = ‘0x’ + binascii;

// Now, you’re calling the contract with this selector

return await contract . at ( selector ) call ( ‘ getTokenDepositAmount ‘ , inputToken ) ;

} catch (error) {

console.

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Creating a Copy Trader on Binance using Websocket API

As a copy trader, you will need to monitor the market and execute trades automatically. One of the most effective ways to achieve this is by leveraging the WebSocket API provided by Binance. However, for beginners, navigating the documentation can be a bit overwhelming.

In this article, we will walk through the key steps to create a simple copy trader on Binance using their Websocket API. We will cover the essentials and provide a step-by-step guide to get you started.

About Websocket API

The WebSocket API allows you to establish a two-way communication channel with Binance. It provides real-time updates, allowing your copy trader to react quickly to changes in the market.

To get started, you will need:

• A registered Binance account for WebSocket API.

• Familiarity with JavaScript programming language (optional but recommended).

Setting up WebSocket connection

Create a new file named index.js in your project directory and add the following code:

const socket = require('ws');
const wss = new ws.Server({ port: 8090 });
wss.on('connection', (ws) => {
console.log('Client connected');
// Handle incoming messages from the main account
ws.on('message', (message) => {
if (message.startsWith('mainAccount')) {
const orderId = message.split(':')[1];
// Perform the operation based on the received order ID
executeTrade(orderID);
}
});
});
wss.listen(8090, () => {
console.log(WebSocket server listening on port 8090);
});

This code sets up a WebSocket server with address ws://localhost:8090. The ws.on('connection') event listener is triggered whenever a new client connects. When the message starts with `mainAccount'', it extracts the order ID from the message and calls theexecuteTradefunction.

To receive updates from the main account, you need to establish a connection via the WebSocket API. Create another file calledwebsocket.jsand add the following code:

const socket = new ws.Client({
host: 'localhost',
port: 8090,
});
socket.on('connect', () => {
console.log('Connected to master account WebSocket');
});
// Send updates to master account
socket.write(master account ${orderId});

Create a new file called copyTrader.jsand add the following code:

const socket = require('./websocket');
const BinanceAPI = require('binance-api');
// Set up Binance API credentials
const apiKey = 'YOUR_API_KEY';
const apiSecret = 'YOUR_API_SECRET';
// Create a new Binance API client
const apiClient = new BinanceAPI({
apiKey: apiKey,
apiSecret: apiSecret,
});
// Function to execute trades
function executeTrade(orderId) {
// Call copy trader function here
console.log(Executing trade ${orderId});
}
// Main loop
setInterval(() => {
socket.emit('message',mainAccount ${orderId});
(1000); // Update every second

This code imports the necessary modules, sets the Binance API credentials, and defines a copyTraderfunction that executes the trades. The main loop uses the WebSocket connection to send updates to the main account.

node index.js

This will start the WebSocket server on port 8090. You can then test the copy trader by sending an update to the main account using a tool like curl` or a trading platform.

Conclusion

To create a simple copy trader on Binance using their Websocket API requires some technical knowledge and configuration.