uniswapv2-path-optimizer

Optimal swap path finder for UniswapV2-based AMM DEX model

Installation

npm i uniswapv2-path-optimizer

Initialize

import Optimizer from "uniswapv2-path-optimizer";
const provider = new providers.JsonRpcProvider("RPC_NODE_URL");
const UniswapFactoryAddress = "0x5C69bEe701ef814a2B6a3EDD4B1652CB9cc5aA6f";
const UniswapRouterAddress = "0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D";

const optimizer = new Optimizer({
    provider,
    factoryAddress: UniswapFactoryAddress,
    routerAddress: UniswapRouterAddress,
    feeBps: 30                  // optional, default 30 (0.3%)
    multicallAddress: "0x..."   // optional for some major chains
});

const WETH = "0x...";
const USDC = "0x...";
// and so on...

// method `optimizer.init` is async function to get token & pair info from blockchain.
// initiate for target tokens, 
// Each element of the array is address of ERC20 tokens
await optimizer.init([WETH, USDC, USDT, DAI, WBTC, BNB, UNI, SUSHI]);

Optimal Path for largest amountOut

const optimalResult = optimizer.getOptimalInPathOffChain({
    from: USDC,     // address of ERC20 token 
    to: WBTC,       // address of ERC20 token 
    amountIn: '1000000', 
    maxLength: 4
});

Optimal Path for smallest amountIn

const optimalResult = optimizer.getOptimalInPathOffChain({
    from: WBTC,     // address of ERC20 token 
    to: USDC,       // address of ERC20 token 
    amountOut: '1000000', 
    maxLength: 4
});

Refresh tokens & pairs

await optimizer.refresh();

Core Entities

UniswapV2PathOptimizer

functions for get tokens & pools

• ready(): boolean
  Check fetching tokens/pools info process is finished.
• tokens(): Token[]
  Returns array of all tokens
• pools(): Pool[]
  Returns array of all pools(pairs)
• getToken(id: number): Token get specific token by index of tokens array
• getTokenByAddress(address: address): Token|undefined
  Get specific token by address
• getTokenId(address: address): number
  Get token's array index
• getPoolByTokenId(tokenAId: number, tokenBId: number): Pool
  Get specific pool by index of pools array
• getPoolByAddress(tokenA: address, tokenB: address): Pool
  Get specific pool by pair tokens' addresses. It doesn't matter the order of the tokens is changed.

functions for setting

• async init(tokens: address[]): Promise<void>
  fetch tokens & pools info from blockchain

• async refresh()
  refresh pools' reserved amounts

• setFee(tokenA: address, tokenB: address, newFeeBps: number)
  change the feeBps of pool

Calculate path on-chain

• async getOutPathsOnChain(props: GetOutPathParams):Promise<AmountsOutResult[]>
  Calculate all possible paths of getAmountsOut function from onChain.
• async getOptimalOutPathOnChain(props: GetOutPathParams):Promise<AmountsOutResult>
  Returns the path with the most optimal value among the results of the getOutPathsOnChain function.
• async getInPathsOnChain(props: GetInPathParams):Promise<AmountsInResult[]>
  Calculate all possible paths of getAmountsIn function from onChain.
• async getOptimalInPathOnChain(props: GetOptimalInPathParams):Promise<AmountsInResult>
  Returns the path with the most optimal value among the results of the getInPathsOnChain function.

Calculate path off-chain

• getOutPathsOffChain(props: GetOutPathParams):AmountsOutResult[]
  Calculate all possible paths of getAmountsOut function from offChain(client-side).

• getOptimalOutPathOffChain(props: GetOptimalOutPathParams):AmountsOutResult
  Returns the path with the most optimal value among the results of the getOutPathsOffChain function.

• getInPathsOffChain(props: GetInPathParams):AmountsInResult[]
  Calculate all possible paths of getAmountsIn function from offChain(client-side).

• getOptimalInPathOffChain(props: GetOptimalInPathParams):AmountsInResult
  Returns the path with the most optimal value among the results of the getInPathsOffChain function.

Basic calculator

• quote(tokenInId: number, tokenOutId: number, amountIn: BigNumberish): BigNumber

• getAmountOut(tokenAId: number, tokenBId: number, amountIn: BigNumberish, priceImpact?:boolean)
priceImpact: boolean if false, calculates without considering the fee. default: true

• getAmountIn(tokenAId: number, tokenBId: number, amountOut: BigNumberish, priceImpact?:boolean)
priceImpact: boolean if false, calculates without considering the fee. default: true

• getAmountsOut(amountIn: BigNumberish, path: number[], priceImpact?:boolean): BigNumber[]
priceImpact: boolean if false, calculates without considering the fee. default: true

• getAmountsIn(amountOut: BigNumberish, path: number[], priceImpact?:boolean): BigNumber[]
priceImpact: boolean if false, calculates without considering the fee. default: true

PathResult

extended by AmountsInResult, AmountsOutResult

Properties

property	type
path	TokenWithAmount[]
amountIn	BigNumber
amountOut	BigNumber

Methods

• format(): String[]
  returns array of formatted strings from amounts in path tokens using tokens' own decimals.

• formatWithoutPriceImpact(): String[]
  returns array of formatted strings from amountsWithoutPriceImpact in path tokens using tokens' own decimals.

• priceImpactBps(): number
  returns price impact when swapping with path in basis point.
  ex) 1234 => 12.34% (0.1234)

• amountInWithToken():TokenWithAmount
  returns amountIn amount with "from" token info.

• amountOutWithToken():TokenWithAmount
  returns amountOut amount with "to" token info.

TokenWithAmount

Properties

property	type
address	string
symbol	string
decimals	number
amount	BigNumber
amountWithoutPriceImpact	BigNumber

Methods

• format(): string
  returns formatted string from amount using decimals.

• formatWithoutPriceImpact(): string returns formatted string from amountWithoutPriceImpact using decimals.