优雅简洁！在FMZ上用200行代码接入了Uniswap V3

优雅简洁！在FMZ上用200行代码接入了Uniswap V3

近些年随着Defi概念的流行，在去中心化金融（DeFi）领域，Uniswap V3是最受关注的话题之一。作为领先的去中心化交换协议，Uniswap V3提供了更高效，更安全，更优秀的用户体验。现在，只需要200行代码，交易员和开发人员就可以在FMZ平台上轻松访问Uniswap V3。

FMZ是一个量化交易平台，支持数量交易策略的开发、回测和实盘部署。其易于使用的界面和强大的功能不难理解为为什么FMZ正在成为DeFi交易员和开发人员的首选。

将Uniswap V3整合到FMZ的过程简单易懂，只需要200行代码即可完成。这意味着，即使您是代码新手，也可以在FMZ上轻松连接Uniswap V3并立即开始交易。

FMZ已经封装了一系列的web3基础功能，除了Uniswap之外也可以用很少的代码封装其它的DEX交易所。接下来就让我带你一起零基础开始学习defi应用中的概念与技术，鉴于篇幅原因，以下描述尽量采用最简单易懂的方式，可能不是十分严谨，但是便于理解。

FMZ平台公开的「Uniswap V3 交易类库」

代码如下：

/* jshint esversion: 7 */

const ABI_Route = '[{"inputs":[{"internalType":"address","name":"_factoryV2","type":"address"},{"internalType":"address","name":"factoryV3","type":"address"},{"internalType":"address","name":"_positionManager","type":"address"},{"internalType":"address","name":"_WETH9","type":"address"}],"stateMutability":"nonpayable","type":"constructor"},{"inputs":[],"name":"WETH9","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveMax","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveMaxMinusOne","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveZeroThenMax","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"}],"name":"approveZeroThenMaxMinusOne","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes","name":"data","type":"bytes"}],"name":"callPositionManager","outputs":[{"internalType":"bytes","name":"result","type":"bytes"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes[]","name":"paths","type":"bytes[]"},{"internalType":"uint128[]","name":"amounts","type":"uint128[]"},{"internalType":"uint24","name":"maximumTickDivergence","type":"uint24"},{"internalType":"uint32","name":"secondsAgo","type":"uint32"}],"name":"checkOracleSlippage","outputs":[],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"uint24","name":"maximumTickDivergence","type":"uint24"},{"internalType":"uint32","name":"secondsAgo","type":"uint32"}],"name":"checkOracleSlippage","outputs":[],"stateMutability":"view","type":"function"},{"inputs":[{"components":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMinimum","type":"uint256"}],"internalType":"struct IV3SwapRouter.ExactInputParams","name":"params","type":"tuple"}],"name":"exactInput","outputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"tokenIn","type":"address"},{"internalType":"address","name":"tokenOut","type":"address"},{"internalType":"uint24","name":"fee","type":"uint24"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMinimum","type":"uint256"},{"internalType":"uint160","name":"sqrtPriceLimitX96","type":"uint160"}],"internalType":"struct IV3SwapRouter.ExactInputSingleParams","name":"params","type":"tuple"}],"name":"exactInputSingle","outputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"bytes","name":"path","type":"bytes"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint256","name":"amountInMaximum","type":"uint256"}],"internalType":"struct IV3SwapRouter.ExactOutputParams","name":"params","type":"tuple"}],"name":"exactOutput","outputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"tokenIn","type":"address"},{"internalType":"address","name":"tokenOut","type":"address"},{"internalType":"uint24","name":"fee","type":"uint24"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint256","name":"amountInMaximum","type":"uint256"},{"internalType":"uint160","name":"sqrtPriceLimitX96","type":"uint160"}],"internalType":"struct IV3SwapRouter.ExactOutputSingleParams","name":"params","type":"tuple"}],"name":"exactOutputSingle","outputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[],"name":"factory","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[],"name":"factoryV2","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amount","type":"uint256"}],"name":"getApprovalType","outputs":[{"internalType":"enum IApproveAndCall.ApprovalType","name":"","type":"uint8"}],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"token0","type":"address"},{"internalType":"address","name":"token1","type":"address"},{"internalType":"uint256","name":"tokenId","type":"uint256"},{"internalType":"uint256","name":"amount0Min","type":"uint256"},{"internalType":"uint256","name":"amount1Min","type":"uint256"}],"internalType":"struct IApproveAndCall.IncreaseLiquidityParams","name":"params","type":"tuple"}],"name":"increaseLiquidity","outputs":[{"internalType":"bytes","name":"result","type":"bytes"}],"stateMutability":"payable","type":"function"},{"inputs":[{"components":[{"internalType":"address","name":"token0","type":"address"},{"internalType":"address","name":"token1","type":"address"},{"internalType":"uint24","name":"fee","type":"uint24"},{"internalType":"int24","name":"tickLower","type":"int24"},{"internalType":"int24","name":"tickUpper","type":"int24"},{"internalType":"uint256","name":"amount0Min","type":"uint256"},{"internalType":"uint256","name":"amount1Min","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"}],"internalType":"struct IApproveAndCall.MintParams","name":"params","type":"tuple"}],"name":"mint","outputs":[{"internalType":"bytes","name":"result","type":"bytes"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes32","name":"previousBlockhash","type":"bytes32"},{"internalType":"bytes[]","name":"data","type":"bytes[]"}],"name":"multicall","outputs":[{"internalType":"bytes[]","name":"","type":"bytes[]"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"deadline","type":"uint256"},{"internalType":"bytes[]","name":"data","type":"bytes[]"}],"name":"multicall","outputs":[{"internalType":"bytes[]","name":"","type":"bytes[]"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"bytes[]","name":"data","type":"bytes[]"}],"name":"multicall","outputs":[{"internalType":"bytes[]","name":"results","type":"bytes[]"}],"stateMutability":"payable","type":"function"},{"inputs":[],"name":"positionManager","outputs":[{"internalType":"address","name":"","type":"address"}],"stateMutability":"view","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"value","type":"uint256"}],"name":"pull","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[],"name":"refundETH","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"value","type":"uint256"},{"internalType":"uint256","name":"deadline","type":"uint256"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"selfPermit","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"nonce","type":"uint256"},{"internalType":"uint256","name":"expiry","type":"uint256"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"selfPermitAllowed","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"nonce","type":"uint256"},{"internalType":"uint256","name":"expiry","type":"uint256"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"selfPermitAllowedIfNecessary","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"value","type":"uint256"},{"internalType":"uint256","name":"deadline","type":"uint256"},{"internalType":"uint8","name":"v","type":"uint8"},{"internalType":"bytes32","name":"r","type":"bytes32"},{"internalType":"bytes32","name":"s","type":"bytes32"}],"name":"selfPermitIfNecessary","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"},{"internalType":"uint256","name":"amountOutMin","type":"uint256"},{"internalType":"address[]","name":"path","type":"address[]"},{"internalType":"address","name":"to","type":"address"}],"name":"swapExactTokensForTokens","outputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountOut","type":"uint256"},{"internalType":"uint256","name":"amountInMax","type":"uint256"},{"internalType":"address[]","name":"path","type":"address[]"},{"internalType":"address","name":"to","type":"address"}],"name":"swapTokensForExactTokens","outputs":[{"internalType":"uint256","name":"amountIn","type":"uint256"}],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"}],"name":"sweepToken","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amountMinimum","type":"uint256"}],"name":"sweepToken","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"uint256","name":"feeBips","type":"uint256"},{"internalType":"address","name":"feeRecipient","type":"address"}],"name":"sweepTokenWithFee","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"address","name":"token","type":"address"},{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"feeBips","type":"uint256"},{"internalType":"address","name":"feeRecipient","type":"address"}],"name":"sweepTokenWithFee","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"int256","name":"amount0Delta","type":"int256"},{"internalType":"int256","name":"amount1Delta","type":"int256"},{"internalType":"bytes","name":"_data","type":"bytes"}],"name":"uniswapV3SwapCallback","outputs":[],"stateMutability":"nonpayable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"}],"name":"unwrapWETH9","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountMinimum","type":"uint256"}],"name":"unwrapWETH9","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"address","name":"recipient","type":"address"},{"internalType":"uint256","name":"feeBips","type":"uint256"},{"internalType":"address","name":"feeRecipient","type":"address"}],"name":"unwrapWETH9WithFee","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"amountMinimum","type":"uint256"},{"internalType":"uint256","name":"feeBips","type":"uint256"},{"internalType":"address","name":"feeRecipient","type":"address"}],"name":"unwrapWETH9WithFee","outputs":[],"stateMutability":"payable","type":"function"},{"inputs":[{"internalType":"uint256","name":"value","type":"uint256"}],"name":"wrapETH","outputs":[],"stateMutability":"payable","type":"function"},{"stateMutability":"payable","type":"receive"}]';
const ABI_Pool = '[{\"inputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"constructor\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"owner\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"amount\",\"type\":\"uint128\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"}],\"name\":\"Burn\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"owner\",\"type\":\"address\"},{\"indexed\":false,\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"amount0\",\"type\":\"uint128\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"amount1\",\"type\":\"uint128\"}],\"name\":\"Collect\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"sender\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"amount0\",\"type\":\"uint128\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"amount1\",\"type\":\"uint128\"}],\"name\":\"CollectProtocol\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"sender\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"paid0\",\"type\":\"uint256\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"paid1\",\"type\":\"uint256\"}],\"name\":\"Flash\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":false,\"internalType\":\"uint16\",\"name\":\"observationCardinalityNextOld\",\"type\":\"uint16\"},{\"indexed\":false,\"internalType\":\"uint16\",\"name\":\"observationCardinalityNextNew\",\"type\":\"uint16\"}],\"name\":\"IncreaseObservationCardinalityNext\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":false,\"internalType\":\"uint160\",\"name\":\"sqrtPriceX96\",\"type\":\"uint160\"},{\"indexed\":false,\"internalType\":\"int24\",\"name\":\"tick\",\"type\":\"int24\"}],\"name\":\"Initialize\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":false,\"internalType\":\"address\",\"name\":\"sender\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"owner\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"amount\",\"type\":\"uint128\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"indexed\":false,\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"}],\"name\":\"Mint\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":false,\"internalType\":\"uint8\",\"name\":\"feeProtocol0Old\",\"type\":\"uint8\"},{\"indexed\":false,\"internalType\":\"uint8\",\"name\":\"feeProtocol1Old\",\"type\":\"uint8\"},{\"indexed\":false,\"internalType\":\"uint8\",\"name\":\"feeProtocol0New\",\"type\":\"uint8\"},{\"indexed\":false,\"internalType\":\"uint8\",\"name\":\"feeProtocol1New\",\"type\":\"uint8\"}],\"name\":\"SetFeeProtocol\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"sender\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"indexed\":false,\"internalType\":\"int256\",\"name\":\"amount0\",\"type\":\"int256\"},{\"indexed\":false,\"internalType\":\"int256\",\"name\":\"amount1\",\"type\":\"int256\"},{\"indexed\":false,\"internalType\":\"uint160\",\"name\":\"sqrtPriceX96\",\"type\":\"uint160\"},{\"indexed\":false,\"internalType\":\"uint128\",\"name\":\"liquidity\",\"type\":\"uint128\"},{\"indexed\":false,\"internalType\":\"int24\",\"name\":\"tick\",\"type\":\"int24\"}],\"name\":\"Swap\",\"type\":\"event\"},{\"inputs\":[{\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"internalType\":\"uint128\",\"name\":\"amount\",\"type\":\"uint128\"}],\"name\":\"burn\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"internalType\":\"uint128\",\"name\":\"amount0Requested\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"amount1Requested\",\"type\":\"uint128\"}],\"name\":\"collect\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"amount0\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"amount1\",\"type\":\"uint128\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"uint128\",\"name\":\"amount0Requested\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"amount1Requested\",\"type\":\"uint128\"}],\"name\":\"collectProtocol\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"amount0\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"amount1\",\"type\":\"uint128\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"factory\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"fee\",\"outputs\":[{\"internalType\":\"uint24\",\"name\":\"\",\"type\":\"uint24\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"feeGrowthGlobal0X128\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"feeGrowthGlobal1X128\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"},{\"internalType\":\"bytes\",\"name\":\"data\",\"type\":\"bytes\"}],\"name\":\"flash\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint16\",\"name\":\"observationCardinalityNext\",\"type\":\"uint16\"}],\"name\":\"increaseObservationCardinalityNext\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint160\",\"name\":\"sqrtPriceX96\",\"type\":\"uint160\"}],\"name\":\"initialize\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"liquidity\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"\",\"type\":\"uint128\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"maxLiquidityPerTick\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"\",\"type\":\"uint128\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"},{\"internalType\":\"uint128\",\"name\":\"amount\",\"type\":\"uint128\"},{\"internalType\":\"bytes\",\"name\":\"data\",\"type\":\"bytes\"}],\"name\":\"mint\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"amount0\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"amount1\",\"type\":\"uint256\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"name\":\"observations\",\"outputs\":[{\"internalType\":\"uint32\",\"name\":\"blockTimestamp\",\"type\":\"uint32\"},{\"internalType\":\"int56\",\"name\":\"tickCumulative\",\"type\":\"int56\"},{\"internalType\":\"uint160\",\"name\":\"secondsPerLiquidityCumulativeX128\",\"type\":\"uint160\"},{\"internalType\":\"bool\",\"name\":\"initialized\",\"type\":\"bool\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint32[]\",\"name\":\"secondsAgos\",\"type\":\"uint32[]\"}],\"name\":\"observe\",\"outputs\":[{\"internalType\":\"int56[]\",\"name\":\"tickCumulatives\",\"type\":\"int56[]\"},{\"internalType\":\"uint160[]\",\"name\":\"secondsPerLiquidityCumulativeX128s\",\"type\":\"uint160[]\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"bytes32\",\"name\":\"\",\"type\":\"bytes32\"}],\"name\":\"positions\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"liquidity\",\"type\":\"uint128\"},{\"internalType\":\"uint256\",\"name\":\"feeGrowthInside0LastX128\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"feeGrowthInside1LastX128\",\"type\":\"uint256\"},{\"internalType\":\"uint128\",\"name\":\"tokensOwed0\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"tokensOwed1\",\"type\":\"uint128\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"protocolFees\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"token0\",\"type\":\"uint128\"},{\"internalType\":\"uint128\",\"name\":\"token1\",\"type\":\"uint128\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint8\",\"name\":\"feeProtocol0\",\"type\":\"uint8\"},{\"internalType\":\"uint8\",\"name\":\"feeProtocol1\",\"type\":\"uint8\"}],\"name\":\"setFeeProtocol\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"slot0\",\"outputs\":[{\"internalType\":\"uint160\",\"name\":\"sqrtPriceX96\",\"type\":\"uint160\"},{\"internalType\":\"int24\",\"name\":\"tick\",\"type\":\"int24\"},{\"internalType\":\"uint16\",\"name\":\"observationIndex\",\"type\":\"uint16\"},{\"internalType\":\"uint16\",\"name\":\"observationCardinality\",\"type\":\"uint16\"},{\"internalType\":\"uint16\",\"name\":\"observationCardinalityNext\",\"type\":\"uint16\"},{\"internalType\":\"uint8\",\"name\":\"feeProtocol\",\"type\":\"uint8\"},{\"internalType\":\"bool\",\"name\":\"unlocked\",\"type\":\"bool\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"int24\",\"name\":\"tickLower\",\"type\":\"int24\"},{\"internalType\":\"int24\",\"name\":\"tickUpper\",\"type\":\"int24\"}],\"name\":\"snapshotCumulativesInside\",\"outputs\":[{\"internalType\":\"int56\",\"name\":\"tickCumulativeInside\",\"type\":\"int56\"},{\"internalType\":\"uint160\",\"name\":\"secondsPerLiquidityInsideX128\",\"type\":\"uint160\"},{\"internalType\":\"uint32\",\"name\":\"secondsInside\",\"type\":\"uint32\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"recipient\",\"type\":\"address\"},{\"internalType\":\"bool\",\"name\":\"zeroForOne\",\"type\":\"bool\"},{\"internalType\":\"int256\",\"name\":\"amountSpecified\",\"type\":\"int256\"},{\"internalType\":\"uint160\",\"name\":\"sqrtPriceLimitX96\",\"type\":\"uint160\"},{\"internalType\":\"bytes\",\"name\":\"data\",\"type\":\"bytes\"}],\"name\":\"swap\",\"outputs\":[{\"internalType\":\"int256\",\"name\":\"amount0\",\"type\":\"int256\"},{\"internalType\":\"int256\",\"name\":\"amount1\",\"type\":\"int256\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"int16\",\"name\":\"\",\"type\":\"int16\"}],\"name\":\"tickBitmap\",\"outputs\":[{\"internalType\":\"uint256\",\"name\":\"\",\"type\":\"uint256\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"tickSpacing\",\"outputs\":[{\"internalType\":\"int24\",\"name\":\"\",\"type\":\"int24\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"int24\",\"name\":\"\",\"type\":\"int24\"}],\"name\":\"ticks\",\"outputs\":[{\"internalType\":\"uint128\",\"name\":\"liquidityGross\",\"type\":\"uint128\"},{\"internalType\":\"int128\",\"name\":\"liquidityNet\",\"type\":\"int128\"},{\"internalType\":\"uint256\",\"name\":\"feeGrowthOutside0X128\",\"type\":\"uint256\"},{\"internalType\":\"uint256\",\"name\":\"feeGrowthOutside1X128\",\"type\":\"uint256\"},{\"internalType\":\"int56\",\"name\":\"tickCumulativeOutside\",\"type\":\"int56\"},{\"internalType\":\"uint160\",\"name\":\"secondsPerLiquidityOutsideX128\",\"type\":\"uint160\"},{\"internalType\":\"uint32\",\"name\":\"secondsOutside\",\"type\":\"uint32\"},{\"internalType\":\"bool\",\"name\":\"initialized\",\"type\":\"bool\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"token0\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"token1\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"}]'
const ABI_Factory = '[{\"inputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"constructor\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"},{\"indexed\":true,\"internalType\":\"int24\",\"name\":\"tickSpacing\",\"type\":\"int24\"}],\"name\":\"FeeAmountEnabled\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"oldOwner\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"newOwner\",\"type\":\"address\"}],\"name\":\"OwnerChanged\",\"type\":\"event\"},{\"anonymous\":false,\"inputs\":[{\"indexed\":true,\"internalType\":\"address\",\"name\":\"token0\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"address\",\"name\":\"token1\",\"type\":\"address\"},{\"indexed\":true,\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"},{\"indexed\":false,\"internalType\":\"int24\",\"name\":\"tickSpacing\",\"type\":\"int24\"},{\"indexed\":false,\"internalType\":\"address\",\"name\":\"pool\",\"type\":\"address\"}],\"name\":\"PoolCreated\",\"type\":\"event\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"tokenA\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"tokenB\",\"type\":\"address\"},{\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"}],\"name\":\"createPool\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"pool\",\"type\":\"address\"}],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"},{\"internalType\":\"int24\",\"name\":\"tickSpacing\",\"type\":\"int24\"}],\"name\":\"enableFeeAmount\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"uint24\",\"name\":\"\",\"type\":\"uint24\"}],\"name\":\"feeAmountTickSpacing\",\"outputs\":[{\"internalType\":\"int24\",\"name\":\"\",\"type\":\"int24\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"},{\"internalType\":\"uint24\",\"name\":\"\",\"type\":\"uint24\"}],\"name\":\"getPool\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"owner\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"\",\"type\":\"address\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[],\"name\":\"parameters\",\"outputs\":[{\"internalType\":\"address\",\"name\":\"factory\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"token0\",\"type\":\"address\"},{\"internalType\":\"address\",\"name\":\"token1\",\"type\":\"address\"},{\"internalType\":\"uint24\",\"name\":\"fee\",\"type\":\"uint24\"},{\"internalType\":\"int24\",\"name\":\"tickSpacing\",\"type\":\"int24\"}],\"stateMutability\":\"view\",\"type\":\"function\"},{\"inputs\":[{\"internalType\":\"address\",\"name\":\"_owner\",\"type\":\"address\"}],\"name\":\"setOwner\",\"outputs\":[],\"stateMutability\":\"nonpayable\",\"type\":\"function\"}]'

let ContractV3Factory = "0x1F98431c8aD98523631AE4a59f267346ea31F984"
let ContractV3SwapRouterV2 = "0x68b3465833fb72A70ecDF485E0e4C7bD8665Fc45"


function computePoolPrice(decimals0, decimals1, sqrtPriceX96) {
    [decimals0, decimals1, sqrtPriceX96] = [decimals0, decimals1, sqrtPriceX96].map(BigInt);
    const TWO = BigInt(2);
    const TEN = BigInt(10);
    const SIX_TENTH = BigInt(1000000);
    const Q192 = (TWO ** BigInt(96)) ** TWO;
    return (
        Number((sqrtPriceX96 ** TWO * TEN ** decimals0 * SIX_TENTH) / (Q192 * TEN ** decimals1)) /
        Number(SIX_TENTH)
    );
}

function toAmount(s, decimals) {
    return Number((BigDecimal(BigInt(s))/BigDecimal(Math.pow(10, decimals))).toString())
}

function toInnerAmount(n, decimals) {
    return (BigDecimal(n)*BigDecimal(Math.pow(10,decimals))).toFixed(0)
}

$.NewUniswapV3 = function(e) {
    e = e || exchange
    if (e.GetName() !== 'Web3') {
        panic("only support Web3 exchange")
    }


    let self = {
        tokenInfo: {},
        walletAddress: e.IO("address"),
        pool: {}
    }

    // register
    e.IO("abi", ContractV3Factory, ABI_Factory)
    e.IO("abi", ContractV3SwapRouterV2, ABI_Route)

    self.addToken = function(name, address) {
        let ret = e.IO("api", address, "decimals")
        if (!ret) {
            throw "get token decimals failed"
        }
        let decimals = Number(ret)
        self.tokenInfo[name] = {
            name: name,
            decimals: decimals,
            address: address
        }
    }
    self.waitMined = function(tx) {
        while (true) {
            Sleep(1000)
            let info = e.IO("api", "eth", "eth_getTransactionReceipt", tx)
            if (info && info.gasUsed) {
                return true
            }
            Log('Transaction not yet mined', tx)
        }
    }

    self.swapToken = function(tokenIn, amountInDecimal, tokenOut, options) {
        // options like {gasPrice: 11, gasLimit: 111, nonce: 111}
        let tokenInInfo = self.tokenInfo[tokenIn]
        let tokenOutInfo = self.tokenInfo[tokenOut]
        if (!tokenInInfo) {
            throw "not found token info " + tokenIn
        }

        if (!tokenOutInfo) {
            throw "not found token info " + tokenOut
        }
        
        let amountIn = toInnerAmount(amountInDecimal, tokenInInfo.decimals)
        let recipientAddress = self.walletAddress
        if (tokenInInfo.name != 'ETH') {
            let allowanceAmount = e.IO("api", tokenInInfo.address, "allowance", self.walletAddress, ContractV3SwapRouterV2);
            let realAmount = toAmount(allowanceAmount, tokenInInfo.decimals)
            if (realAmount < toAmount(amountIn, tokenInInfo.decimals)) {
                Log("realAmount is", realAmount, "too small, try to approve large amount")
                if (tokenInInfo.name == 'USDT') {
                    // As described in Tether code: To change the approve amount you first have to reduce the addresses allowance to 0 calling approve(spender, 0)
                    let txApprove = e.IO("api", tokenInInfo.address, "approve", ContractV3SwapRouterV2, 0)
                    if (!txApprove) {
                        throw "approve error"
                    }
                    Log("wait reduce approve", txApprove)
                    self.waitMined(txApprove)
                }

                let txApprove = e.IO("api", tokenInInfo.address, "approve", ContractV3SwapRouterV2, '0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff');
                if (!txApprove) {
                    throw "approve error"
                }
                Log("wait approve", txApprove)
                self.waitMined(txApprove)
                Log("approve success amountIn", amountIn)
            } else {
                Log("allowance", realAmount, "no need to approve")
            }
        }

        if (tokenOutInfo.name == 'ETH' || tokenOutInfo.address.toLowerCase() == '0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2') {
            /*
            ADDRESS_THIS https://degencode.substack.com/p/uniswapv3-multicall
            https://etherscan.io/address/0x68b3465833fb72a70ecdf485e0e4c7bd8665fc45#code
            */
            recipientAddress = '0x0000000000000000000000000000000000000002'
        }

        let swapToken = e.IO("encode", ContractV3SwapRouterV2, "swapExactTokensForTokens", amountIn, 1, [tokenInInfo.address, tokenOutInfo.address], recipientAddress)
        let data = [swapToken]
        if (tokenOutInfo.name == 'ETH') {
            data.push(e.IO("encode", ContractV3SwapRouterV2, "unwrapWETH9(uint256,address)", 1, self.walletAddress))
        }
        let tx = e.IO("api", ContractV3SwapRouterV2, "multicall(uint256,bytes[])", (tokenInInfo.name == 'ETH' ? amountIn : 0), (new Date().getTime() / 1000) + 3600, data, options || {})
        if (tx) {
            Log("tx: ", tx)
            self.waitMined(tx)
            Log("swap", tokenInInfo.name, "to", tokenOutInfo.name, "success")
            return true
        } else {
            Log("trans error")
            return false
        }
    }

    self.getETHBalance = function(address) {
        return toAmount(e.IO("api", "eth", "eth_getBalance", address || self.walletAddress, "latest"), 18)
    }

    self.balanceOf = function(token, address) {
        let tokenInfo = self.tokenInfo[token]
        if (!tokenInfo) {
            throw "not found token info " + token
        }

        return toAmount(e.IO("api", tokenInfo.address, "balanceOf", address || self.walletAddress), tokenInfo.decimals)
    }

    self.sendETH = function(to, amount, options) {
        return e.IO("api", "eth", "send", to, toInnerAmount(amount, 18), options || {})
    }

    self.getPrice = function(pair) {
        let arr = pair.split('_')
        let token0 = self.tokenInfo[arr[0]]
        if (!token0) {
            throw "token " + arr[0] + "not found"
        }
        let token1 = self.tokenInfo[arr[1]]
        if (!token1) {
            throw "token " + arr[1] + "not found"
        }
        let reverse = false
        if (BigInt(token0.address) > BigInt(token1.address)) {
            let tmp = token0
            token0 = token1
            token1 = tmp
            reverse = true
        }
        let key = token0.address + '/' + token1.address
        if (typeof(self.pool[key]) == 'undefined') {
            let pool = e.IO("api", ContractV3Factory, "getPool", token0.address, token1.address, 3000)
            if (pool) {
                self.pool[key] = pool
                // register pool address
                e.IO("abi", pool, ABI_Pool)
            }
        }
        if (typeof(self.pool[key]) == 'undefined') {
            throw "pool " + pair + " not found"
        }

        let slot0 = e.IO("api", self.pool[key], "slot0")

        if (!slot0) {
            return null
        }

        let price = computePoolPrice(token0.decimals, token1.decimals, slot0.sqrtPriceX96)
        if (reverse) {
            price = 1 / price
        }
        return price
    }

    return self
}

$.testUniswap = function() {
    let ex = $.NewUniswapV3()
    Log("walletAddress: ", ex.walletAddress)
    let tokenAddressMap = {
        "ETH": "0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2", // WETH
        "USDT": "0xdac17f958d2ee523a2206206994597c13d831ec7",
        "1INCH": "0x111111111117dC0aa78b770fA6A738034120C302",
    }
    for (let name in tokenAddressMap) {
        ex.addToken(name, tokenAddressMap[name])
    }

    Log(ex.getPrice('ETH_USDT'))
    Log(ex.getPrice('1INCH_USDT'))
    // swap 0.01 ETH to USDT
    Log(ex.swapToken('ETH', 0.01, 'USDT'))
    let usdtBalance = ex.balanceOf('USDT')
    Log("balance of USDT", usdtBalance)
    // swap reverse
    Log(ex.swapToken('USDT', usdtBalance, 'ETH'))
    
    Log("balance of ETH", ex.getETHBalance())
    
    // Log(ex.sendETH('0x11111', 0.02))
}

以太坊网络

以太坊网络可以理解为一个软件基础设施，在这个网络上可以部署运行各种智能合约，智能合约有各种各样的功能、应用场景。运行以太坊客户端的设备就构成了以太坊网络中的节点。

Uniswap V3中的一些概念

不熟悉Uniswap V3协议的同学，这里需要先简单了解几个概念。Uniswap V3也是在以太坊上部署运行的智能合约。

1、路由（Route）：路由也是一个智能合约，用于管理token兑换。 2、池（Pool）：池也是一个智能合约，用于存储两种以太坊代币，并在这两种代币之间进行交换。 3、工厂合约（Factory）：工厂合约是用来创建池的智能合约。 4、ABI：（应用程序二进制接口）是一种规范，用于描述智能合约如何与外部世界互相通信。它指定了智能合约的函数名称，参数类型和返回值类型，以及如何编码和解码数据，并确定了智能合约的外部接口。可以理解为要调用某个接口，就必须按照接口约定的标准调用，而ABI中记录的就是约定的一系列标准。

一旦智能合约在以太坊上部署，就有一个地址。

剖析Uniswap V3 交易类库的代码

Uniswap V3 交易类库代码主要分为4个部分，我们来逐一讲解。

Part 1：与Uniswap V3交互时用到的常量

const ABI_Route = '[{"inputs":[{"internalType":"address...
const ABI_Pool = '[{\"inputs\":[],\"stateMutability\":\"nonpayable...
const ABI_Factory = '[{\"inputs\":[],\"stateMutability\":\"...

let ContractV3Factory = "0x1F98431c8aD98523631AE4a59f267346ea31F984"
let ContractV3SwapRouterV2 = "0x68b3465833fb72A70ecDF485E0e4C7bD8665Fc45"

通过上面的基础概念预热，这里就很容易理解啦。

ABI_Route这个常量储存的字符串就是路由智能合约的ABI。 ABI_Pool储存池合约的ABI。 ABI_Factory工厂合约的ABI。

由于这些字符串很长，所以只是节选。这些内容就给程序提供了调用智能合约方法的标准（例如这个智能合约接口的参数有什么，几个参数，都是什么类型，返回数据是什么类型等）。

刚才我们也提过，一旦智能合约部署在以太坊，就有一个地址。

ContractV3Factory：记录了工厂合约的地址。 ContractV3SwapRouterV2：Uniswap V3的router V2地址，注意Uniswap有V1、V2，Uniswap V3 的router也有V1、V2之分，不同的合约地址是不一样的。

Part2：工具函数

1、computePoolPrice函数用来计算池中token的价格。

function computePoolPrice(decimals0, decimals1, sqrtPriceX96) {
    [decimals0, decimals1, sqrtPriceX96] = [decimals0, decimals1, sqrtPriceX96].map(BigInt);   // 使用BigInt函数处理，因为JavaScript语言数值精度的原因，需要使用FMZ的一个底层处理函数BigInt来处理
    const TWO = BigInt(2);     // 定义常量2用于计算
    const TEN = BigInt(10);    // 定义常量10用于计算
    const SIX_TENTH = BigInt(1000000);    // 定义常量10的6次方，即1e6
    const Q192 = (TWO ** BigInt(96)) ** TWO;  // 2^192
    return (
        Number((sqrtPriceX96 ** TWO * TEN ** decimals0 * SIX_TENTH) / (Q192 * TEN ** decimals1)) /
        Number(SIX_TENTH)
    );
}

假如交易对是ETH_USDT，那么token0是ETH，token1是USDT。decimals0就是token0的精度数据，decimals1就是token1的精度数据。sqrtPriceX96就是价格相关数据（并不是直接的价格数值），该数据可以从池合约的slot0方法获取。

sqrtPriceX96 : The current price of the pool as a sqrt(token1/token0) Q64.96 value Q64.96 是一种数据处理储存标准。

decimals0，decimals1， sqrtPriceX96这三个数据作为参数传入computePoolPrice函数即可计算出交易对ETH_USDT的价格。该函数最后return语句中的算法就是把sqrtPriceX96还原成token1/token0的过程。例如此时池里token0（ETH）个数是1个，token1（USDT）个数是1100个。那么1100/1=1100，当前交易对ETH_USDT池中的价格就是1100。

2、toAmount函数用来把链上数值数据转换成可读数据。

function toAmount(s, decimals) {
    return Number((BigDecimal(BigInt(s))/BigDecimal(Math.pow(10, decimals))).toString())
}

简单说，例如一个ETH代币在链上表示数量时是1e18，即10的18次方，因为ETH的精度数据是18。并非所有代币精度都是18，USDT的精度就和ETH的精度不一样。toAmount函数就是将1e18转换成1。

3、toInnerAmount函数则和toAmount相反，是将可读数据转换成链上使用的数值。

function toInnerAmount(n, decimals) {
    return (BigDecimal(n)*BigDecimal(Math.pow(10,decimals))).toFixed(0)
}

接下来我们来一起剖析「Uniswap V3 交易类库」的代码。

Part3：Uniswap V3操作对象的构造函数

这个模板类库的核心就是Uniswap V3操作对象，这个对象实现了在Uniswap V3上的基本操作。后续可能还会升级更多的功能。通过剖析这个代码例子，即使不使用FMZ平台，也会增加对Uniswap这个DEX的各个环节流程、细节的认识和理解，目前我们就来学习下这些基本的功能是如何在FMZ上设计实现的。

Uniswap V3操作对象的构造函数代码：

$.NewUniswapV3 = function(e) {
    e = e || exchange                          // 如果没有传参数e，就使用交易所对象exchange，即策略上第一个添加的交易所
    if (e.GetName() !== 'Web3') {              // 判断交易所对象是否是Web3，因为这个模板只支持Web3交易所对象
        panic("only support Web3 exchange")
    }


    let self = {                               // 当前函数是一个构造函数，构造的对象就是self这个对象
        tokenInfo: {},                         // self对象的成员变量，用于记录token的注册信息
        walletAddress: e.IO("address"),        // 记录当前交易所对象绑定的钱包地址
        pool: {}                               // 用于记录注册的池信息
    }

    // register
    e.IO("abi", ContractV3Factory, ABI_Factory)       // 注册工厂合约的ABI
    e.IO("abi", ContractV3SwapRouterV2, ABI_Route)    // 注册路由合约的ABI

    self.addToken = function(name, address) {         // 用于注册token
        let ret = e.IO("api", address, "decimals")    // 调用decimals方法，获取token精度信息
        if (!ret) {
            throw "get token decimals failed"
        }
        let decimals = Number(ret)
        self.tokenInfo[name] = {
            name: name,
            decimals: decimals,
            address: address
        }
    }
    self.waitMined = function(tx) {             // 用于等待以太坊上某个操作的结果，哈希为tx参数
        while (true) {
            Sleep(1000)
            let info = e.IO("api", "eth", "eth_getTransactionReceipt", tx)  // 查询结果使用eth_getTransactionReceipt方法，没有查询到，循环继续查询
            if (info && info.gasUsed) {
                return true
            }
            Log('Transaction not yet mined', tx)
        }
    }

    self.swapToken = function(tokenIn, amountInDecimal, tokenOut, options) {   // 用于token兑换
        // options like {gasPrice: 11, gasLimit: 111, nonce: 111}
        let tokenInInfo = self.tokenInfo[tokenIn]      // 拿到兑换出去的token的信息
        let tokenOutInfo = self.tokenInfo[tokenOut]    // 拿到兑换回来的token的信息
        if (!tokenInInfo) {
            throw "not found token info " + tokenIn
        }

        if (!tokenOutInfo) {
            throw "not found token info " + tokenOut
        }
        
        let amountIn = toInnerAmount(amountInDecimal, tokenInInfo.decimals)  // 转换为智能合约上使用的数据
        let recipientAddress = self.walletAddress
        if (tokenInInfo.name != 'ETH') {
            let allowanceAmount = e.IO("api", tokenInInfo.address, "allowance", self.walletAddress, ContractV3SwapRouterV2);   // 查询授权的数量
            let realAmount = toAmount(allowanceAmount, tokenInInfo.decimals)
            if (realAmount < toAmount(amountIn, tokenInInfo.decimals)) {    // 如果授权数量不足
                Log("realAmount is", realAmount, "too small, try to approve large amount")
                if (tokenInInfo.name == 'USDT') {
                    // As described in Tether code: To change the approve amount you first have to reduce the addresses allowance to 0 calling approve(spender, 0)
                    let txApprove = e.IO("api", tokenInInfo.address, "approve", ContractV3SwapRouterV2, 0)  // 如果授权的token是USDT，需要先授权为0
                    if (!txApprove) {
                        throw "approve error"
                    }
                    Log("wait reduce approve", txApprove)
                    self.waitMined(txApprove)
                }

                let txApprove = e.IO("api", tokenInInfo.address, "approve", ContractV3SwapRouterV2, '0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff');  // 授权Router合约操作钱包的代币
                if (!txApprove) {
                    throw "approve error"
                }
                Log("wait approve", txApprove)
                self.waitMined(txApprove)
                Log("approve success amountIn", amountIn)
            } else {
                Log("allowance", realAmount, "no need to approve")
            }
        }

        if (tokenOutInfo.name == 'ETH' || tokenOutInfo.address.toLowerCase() == '0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2') {
            /*
            ADDRESS_THIS https://degencode.substack.com/p/uniswapv3-multicall
            https://etherscan.io/address/0x68b3465833fb72a70ecdf485e0e4c7bd8665fc45#code
            */
            recipientAddress = '0x0000000000000000000000000000000000000002'
            // 其它币换成 WETH的时候，要让合约HOLD住WETH才可以赎回
        }

        let swapToken = e.IO("encode", ContractV3SwapRouterV2, "swapExactTokensForTokens", amountIn, 1, [tokenInInfo.address, tokenOutInfo.address], recipientAddress)   // 打包swapExactTokensForTokens调用
        let data = [swapToken]
        if (tokenOutInfo.name == 'ETH') {    // 如果兑换时，兑换回来的token是ETH，这里实际是WETH，则需要解包
            data.push(e.IO("encode", ContractV3SwapRouterV2, "unwrapWETH9(uint256,address)", 1, self.walletAddress))   // 所以这里再打包一个unwrapWETH9解包调用
        }
        let tx = e.IO("api", ContractV3SwapRouterV2, "multicall(uint256,bytes[])", (tokenInInfo.name == 'ETH' ? amountIn : 0), (new Date().getTime() / 1000) + 3600, data, options || {})   // 使用multicall执行这些打包的操作（swapExactTokensForTokens、unwrapWETH9）
        if (tx) {
            Log("tx: ", tx)
            self.waitMined(tx)
            Log("swap", tokenInInfo.name, "to", tokenOutInfo.name, "success")
            return true
        } else {
            Log("trans error")
            return false
        }
    }

    self.getETHBalance = function(address) {   // 查询钱包的ETH余额
        return toAmount(e.IO("api", "eth", "eth_getBalance", address || self.walletAddress, "latest"), 18)
    }

    self.balanceOf = function(token, address) {  // 查询钱包的某个token余额（根据参数确定）
        let tokenInfo = self.tokenInfo[token]
        if (!tokenInfo) {
            throw "not found token info " + token