@stochain/dex-swap

DEX swap utilities for PancakeSwap and other decentralized exchanges.

Installation

npm install @stochain/dex-swap ethers simple-pancakeswap-sdk

Features

• 🥞 PancakeSwap integration
• 💱 Token swap utilities
• 📊 Exchange rate calculation
• ✅ Swap validation
• 🎣 React hooks for swap management
• 💰 Token balance queries

Usage

Basic Swap with PancakeSwap

import { trade, swap } from '@stochain/dex-swap';
import { Wallet } from 'ethers';

// Create trade
const tradeContext = await trade({
  ethAddress: '0x...',
  fromTokenAddress: '0x...',
  toTokenAddress: '0x...',
  amount: '1.0',
  slippage: 0.005, // 0.5%
  deadlineMinutes: 20
});

// Execute swap
const wallet = new Wallet('private-key');
const result = await swap(wallet, tradeContext);

React Hook for Swap Management

import { useSwap } from '@stochain/dex-swap';

function SwapScreen() {
  const {
    fromToken,
    toToken,
    setFromToken,
    setToToken,
    fromAmount,
    toAmount,
    handleFromAmountChange,
    handleMaxAmount,
    swapTokens,
    executeSwap,
    isSwapEnabled,
    exchangeRate
  } = useSwap({
    onSwapComplete: () => console.log('Swap completed'),
    onSwapError: (error) => console.error('Swap failed:', error)
  });

  return (
    <View>
      <TextInput
        value={fromAmount}
        onChangeText={handleFromAmountChange}
        placeholder="0.00"
      />
      <Text>Exchange Rate: {exchangeRate}</Text>
      <Text>You will receive: {toAmount}</Text>
      <Button
        title="Swap"
        onPress={executeSwap}
        disabled={!isSwapEnabled()}
      />
    </View>
  );
}

Swap Validation

import { validateSwap } from '@stochain/dex-swap';

const validation = validateSwap(fromToken, toToken, '1.0');

if (!validation.isValid) {
  console.error('Validation errors:', validation.errors);
}

Exchange Rate Calculation

import { calculateExchangeRate } from '@stochain/dex-swap';

const result = calculateExchangeRate(
  fromToken,
  toToken,
  '1.0'
);

console.log('Rate:', result.rate);
console.log('To Amount:', result.toAmount);

Token Balance

import { getTokenBalance, getBNBToken } from '@stochain/dex-swap';
import { Wallet } from 'ethers';

const wallet = new Wallet('private-key');

// Get BNB balance
const bnbToken = await getBNBToken(wallet);
console.log('BNB balance:', bnbToken.balance.val);

// Get ERC20 token balance
const balance = await getTokenBalance(wallet, {
  address: '0x...'
});
console.log('Token balance:', balance.val);

API Reference

PancakeSwap Functions

• trade(params): Create a trade on PancakeSwap
• swap(wallet, tradeContext): Execute swap transaction
• getTokenBalance(wallet, token, providerUrl?): Get token balance
• getBNBToken(wallet): Get BNB token info
• getToken(tokenAddress, chainId): Get token information

Swap Service Functions

• calculateExchangeRate(fromToken, toToken, fromAmount): Calculate exchange rate
• validateSwap(fromToken, toToken, fromAmount): Validate swap parameters
• executeSwap(fromToken, toToken, fromAmount, toAmount): Execute swap
• updateBalancesAfterSwap(...): Update balances after swap

React Hooks

• useSwap(options?): Hook for swap state management

Types

interface Token {
  symbol: string;
  name: string;
  address?: string;
  network: string;
  balance?: string;
  price?: number;
}

interface TradeParams {
  ethAddress: string;
  fromTokenAddress: string;
  toTokenAddress: string;
  amount: string;
  providerUrl?: string;
  slippage?: number;
  deadlineMinutes?: number;
}

interface ValidationResult {
  isValid: boolean;
  errors: string[];
}

License

MIT