@backchain/swap

AMM liquidity pool trading module for the Backchain DeFi ecosystem on opBNB.

Install

npm install @backchain/swap

Quick Start

import { createContext } from '@backchain/core';
import { SwapModule } from '@backchain/swap';

const ctx = await createContext({ provider, signer });
const swap = new SwapModule(ctx);

const quote = await swap.getQuote(ethers.parseEther('0.1'));
const tx = await swap.buyBkc(ethers.parseEther('0.1'), 50); // 0.5% slippage

API

Write Methods

buyBkc(bnbAmount: bigint, slippageBps?: number): Promise<TransactionResponse>

Buy BKC tokens by sending BNB. Uses constant-product AMM pricing. slippageBps defaults to 50 (0.5%).

sellBkc(bkcAmount: bigint, slippageBps?: number): Promise<TransactionResponse>

Sell BKC tokens and receive BNB. slippageBps defaults to 50 (0.5%).

Read Methods

getQuote(bnbAmount: bigint): Promise<bigint>

Returns the estimated BKC output for a given BNB input, accounting for the 0.3% swap fee.

getQuoteBkcToEth(bkcAmount: bigint): Promise<bigint>

Returns the estimated BNB output for a given BKC input, accounting for the 0.3% swap fee.

getCurrentPrice(): Promise<bigint>

Returns the current BKC price in BNB, expressed in 18-decimal wei.

getReserves(): Promise<{ bnbReserve: bigint; bkcReserve: bigint }>

Returns the current BNB and BKC reserves held by the liquidity pool.

getSwapFeeBps(): Promise<number>

Returns the swap fee in basis points (currently 30, i.e. 0.3%).

getStats(): Promise<SwapStats>

Returns aggregated pool statistics including total volume, number of swaps, and TVL.

Notes

• Uses a constant-product AMM (x * y = k).
• All amounts are bigint (ethers.js v6 wei scale).
• Slippage is expressed in basis points (100 bps = 1%).

License

MIT