Getting Started
Hands-on tutorial to start using WardenSwap SDK for developers.
1.Install the package
npm install @wardenswap/bestrate-sdk
2. Install additional dependencies. If already installed, ensure the version of ethers ≥ 5.4.0
npm install ethers
This tutorial focuses on the implementation for BNB Chain. However, it can be applied to the other network in the same way, by changing provider, contract addresses and token list.
Depending on the use cases, you might not need to implement all the steps provided here. However, to integrate the swap page into your own, you will need 1. Getting Quote 2. Approval and 3. Swap.
For Ethereum and Polygon, it has the same implementation as BNB Chain except the parameters mentioned in here.
You can use SDK to easily get quote.
import {
initProvider,
WardenBestRate,
} from "@wardenswap/bestrate-sdk";
import { ethers } from "ethers";
async function getQuote() {
const provider = initProvider("https://bsc-dataseed.binance.org");
const warden = new WardenBestRate(provider, "bsc");
const src = "0xe9e7cea3dedca5984780bafc599bd69add087d56"; // source Token Address: BUSD
const srcDecimals = 18; // source token's decimals
const dest = "0x0feadcc3824e7f3c12f40e324a60c23ca51627fc"; // destination Token Address: WAD
const amountIn = ethers.utils.parseUnits("100", srcDecimals); // amount of source token
const gasPrice = await provider.getGasPrice()
// Get BEST RATE!
const quote = await warden.getQuote(src, dest, amountIn, gasPrice, {
enableSplit: true,
});
console.log(JSON.stringify(quote, null, 2))
return {
quote,
warden,
}
}
The quote response will looks like this. You can use
amountOut to preview to the user, including building the swap params.{
"type": "strategies",
"path": {
"routes": [
{
"address": "0x0dEa19CAb88f45301a83C6b5eAa18E8387546afE",
"id": "0",
"name": "WARDEN"
}
],
"tokens": []
},
"amountOut": "565042446063757949355",
"gasFees": {
"dest": "1913868530378129232",
"unit": "166401",
"usd": "0.338591545617514122"
},
"blockNumber": 16875978,
"routerAddress": "0x451ef8d6b645a60115eb8b8bea76b39c0c761004",
"swapAddress": "0x9cbd1322c3d029d32357808665dcae5c286c7081",
"depositAddress": "0xc95B1750043FCE5dfCc8539835Ea3830Ec002A89"
}
Before the token can be swapped, the user has to approve it first. This part shows the example integrated with the web3-react. After integrating web3-react to our app, we can do this. And we need to connect to user wallet first to let the user confirm approving.
Read about using React to connect wallets like Metamask here: https://medium.com/coinmonks/web3-react-connect-users-to-metamask-or-any-wallet-from-your-frontend-241fd538ed39
import React from 'react';
import { ethers } from 'ethers'
import erc20Abi from './abi/ERC20.abi.json'
import { useWeb3React, Web3ReactProvider } from '@web3-react/core';
import { Web3Provider } from "@ethersproject/providers";
import { WardenBestRate } from '@wardenswap/bestrate-sdk';
function SwapComponent({ wardenClient, srcAddr, destAddr, amountIn }) {
const { active, account, library } = useWeb3React()
const handleApprove = async () => {
if (!active) {
alert("please connect wallet")
return
}
// init erc20 contract for token
const signer = library.getSigner(account).connectUnchecked()
try {
// amountIn can be omitted to approve with MaxUint256 allowance
// return null if no need to be approved
const tx = await wardenClient.approve(signer, srcAddr, amountIn)
console.log("[handleApprove] approve result:", tx)
if (tx !== null) {
await tx.wait()
}
} catch (err) {
console.error("[handleApprove] error:", err)
alert(`Approve error: ${JSON.stringify(err)}`)
}
}
return (
<>
<button onClick={handleApprove}>Approve</button>
</>
)
}
After getting quote, we can send the transaction to the contract to swap with the strategies or split type method depending on the quote result.
import React from 'react';
import { ethers } from 'ethers'
import erc20Abi from './abi/ERC20.abi.json'
import { useWeb3React, Web3ReactProvider } from '@web3-react/core';
import { Web3Provider } from "@ethersproject/providers";
import { WardenBestRate } from '@wardenswap/bestrate-sdk';
function SwapComponent({ wardenClient, srcAddr, destAddr, amountIn }: { wardenClient: WardenBestRate, srcAddr: string, destAddr: string, amountIn: ethers.BigNumber }) {
const { active, account, library } = useWeb3React()
const handleApprove = async () => { ... }
const handleSwap = async () => {
if (!active) {
alert('please connect wallet')
return
}
const signer = library.getSigner(account).connectUnchecked()
try {
const { quote, warden } = await getQuote(srcAddr, destAddr, amountIn)
console.log('[handleSwap] quote:', quote)
// Allow 2% slippage for amount out
const minAmountOut = ethers.BigNumber.from(quote.amountOut).mul(98).div(100)
const tx = await warden.swap(signer, srcAddr, destAddr, amountIn, minAmountOut, quote)
await tx.wait()
} catch (err) {
console.error('[handleSwap] error:', err)
alert(`Swap error: ${JSON.stringify(err)}`)
}
}
return (
<>
<button onClick={handleApprove}>Approve</button>
<button onClick={handleSwap}>Swap</button>
</>
)
}
function getQuote(src, dest, amountIn, amountInDecimal) {
...
}
As the general convention, the native currency or gas will be represented with the address
0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE .Ref:
Code Example:
To use SDK with Polygon, we need to input the different parameters from BSC, as shown in this example.
// This params map is showing the difference params needed for each chain.
// The token address is also different, despite the same symbol.
// See token list for addresses and decimal places
const params = {
// ethereum mainnet chain id: 1
1: {
CHAIN_NAME: 'ethereum',
JSON_RPC_URL: 'YOUR_RPC_URL',
ROUTER_ADDRESS: '0x39f97198c5DbC193EB962c4B3B7e447091A18eAB',
FROM_AMOUNT: ethers.utils.parseUnits('10', 6), // 10 USDC in BigNumber
FROM_ADDR: '0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48', // USDC
TO_ADDR: '0xeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee', // ETH
},
// bsc chain id: 56
56: {
CHAIN_NAME: 'bsc',
JSON_RPC_URL: 'https://bsc-dataseed.binance.org/'
ROUTER_ADDRESS: '0x451ef8D6B645a60115EB8b8bEa76B39C0C761004',
FROM_AMOUNT: ethers.utils.parseUnits('20', 18), // 20 BUSD in BigNumber
FROM_ADDR: '0xe9e7cea3dedca5984780bafc599bd69add087d56', // BUSD
TO_ADDR: '0x0feadcc3824e7f3c12f40e324a60c23ca51627fc', // WAD
},
// polygon chain id: 137
137: {
CHAIN_NAME: 'polygon',
JSON_RPC_URL: 'https://rpc-mainnet.matic.quiknode.pro',
ROUTER_ADDRESS: '0x030B8b7bF245E762736e65c0903295447B898c30',
FROM_AMOUNT: ethers.utils.parseUnits('20', 6), // 20 USDC in BigNumber
FROM_ADDR: '0x2791Bca1f2de4661ED88A30C99A7a9449Aa84174', // USDC
TO_ADDR: '0x7ceB23fD6bC0adD59E62ac25578270cFf1b9f619', // ETH
}
}
// given the params are using for Polygon
const currentParams = params[137]
// get quote
const provider = new ethers.providers.JsonRpcProvider(currentParams.JSON_RPC_URL)
const wardenClient = new WardenBestRate(provider, currentParams.CHAIN_NAME)
const quote = await wardenClient.getQuote(...)
...
// approval
const allowance = await erc20Contract.allowance(account, currentParams.ROUTER_ADDRESS)
...
// swap
const wardenContract = new ethers.Contract(wardenRouterAddress, wardenRouter2Abi, signer)
const swap = await wardenClient.swap(...)
Note: you may detect the chain ID to switch the parameters accordingly.
To use SDK with Optimism and Arbitrum (coming soon), we need to Input both
gasPrice and gasPriceL2 as shown below.const quote = await wardenClient.getQuote(
srcAddr,
destAddr,
amountIn,
gasPrice, // 👈 this should be L1 gas price (Ethereum gas price)
{ gasPriceL2: ethers.utils.parseUnits("0.001", "gwei") }
)
Sometimes certain tools will output
Math.pow(BigInt(2), BigInt(128)) - BigInt(1) because they have @babel/plugin-transform-exponentiation-operator included.If you are using
@babel/preset-env, you can exclude it like this to fix: presets: [
[
'@babel/preset-env',
{
...
exclude: [
...
'transform-exponentiation-operator', // << this line here
],
},
],
],
This error can be caused by the version of Ethers.js not matching the library. We suggest to update the Ethers.js to version newer than 5.4.0
In case you are comfortable to use the latest version of Ethers.js, run this command to upgrade.
npm install ethers@latest
Last modified 1yr ago