Uniswap v2

什么是 best route

下图中用 matic 去 swap bnb， 红框中的swap 路径即为 best route

如何实现

1. 可以设置一个主流币列表然后用主流币作为中转去遍历
2. 使用 uniswap sdk 提供的api besttradeexactin 来计算

示例代码

以 quickswap sdk 为例，其实和uniswap代码都一样只是包名不同

const {
  Fetcher,
  WETH,
  Route,
  Trade,
  TokenAmount,
  TradeType,
  ChainId,
} = require("quickswap-sdk");
const ethers = require("ethers");
// 可以替换为自己的url
const url = "http://127.0.0.1:8545";
const customHttpProvider = new ethers.providers.JsonRpcProvider(url);

const chainId = 1337;
const usdt_address = "0xc2132D05D31c914a87C6611C10748AEb04B58e8F";
const aave_address = "0xD6DF932A45C0f255f85145f286eA0b292B21C90B";
const weth_address = "0x7ceB23fD6bC0adD59E62ac25578270cFf1b9f619";
const dai_address = "0x8f3cf7ad23cd3cadbd9735aff958023239c6a063";
const init = async () => {
  const usdt = await Fetcher.fetchTokenData(
    chainId,
    usdt_address,
    customHttpProvider
  );
  const aave = await Fetcher.fetchTokenData(
    chainId,
    aave_address,
    customHttpProvider
  );

  const weth = await Fetcher.fetchTokenData(
    chainId,
    weth_address,
    customHttpProvider
  );
  const dai = await Fetcher.fetchTokenData(
    chainId,
    dai_address,
    customHttpProvider
  );
  // 需要获取protocol的所有token并组合pair ，但是这样效率太低 所以准备几个主流币作为中间转换币应该没什么问题
  const pairs = await Fetcher.fetchPairData(aave, usdt, customHttpProvider);
  const epairs = await Fetcher.fetchPairData(aave, weth, customHttpProvider);
  const epairs2 = await Fetcher.fetchPairData(weth, usdt, customHttpProvider);
  const epairs3 = await Fetcher.fetchPairData(aave, dai, customHttpProvider);
  const epairs4 = await Fetcher.fetchPairData(dai, usdt, customHttpProvider);
  const route = new Route([pairs], aave);
  // const trade = new Trade(
  //   route,
  //   new TokenAmount(aave, "1000000000000000000"),
  //   TradeType.EXACT_INPUT
  // );
  // console.log(route.path);
  console.log("Mid Price aave --> usdt:", route.midPrice.toSignificant(6));
  const amountIn = new TokenAmount(aave, "1000000000000000000");
  const best = Trade.bestTradeExactIn(
    [pairs, epairs3, epairs4, epairs, epairs2],
    amountIn,
    usdt
    // new TokenAmount(usdt, 1000000)
  );
  // 打印最佳路径
  console.log(best[0].route.path);
};

init();

Uniswap v3

v3 版本的 swap path已经是一个中心化服务来提供查询了

Uniswap/routing-api (github.com)