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  3. Elegant and simple! Accessed Uniswap V3 on FMZ with 200 lines of code

Elegant and simple! Accessed Uniswap V3 on FMZ with 200 lines of code

Author: FMZ~Lydia, Created: 2023-02-09 14:34:40, Updated: 2023-09-18 19:38:35

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Elegant and simple! Accessed Uniswap V3 on FMZ with 200 lines of code

With the popularity of Defi concept in recent years, Uniswap V3 is one of the most popular topics in the field of decentralized finance (DeFi). As a leading decentralized swap protocol, Uniswap V3 provides a more efficient, safer and better user experience. Now, with only 200 lines of code, traders and developers can access Uniswap V3 on the FMZ platform easily.

FMZ is a quantitative trading platform that supports the development, backtesting and real market deployment of quantitative trading strategies. Its easy-to-use interface and powerful functions are not difficult to understand why FMZ is becoming the first choice of DeFi traders and developers.

The process of integrating Uniswap V3 into FMZ is simple and easy to understand, requiring only 200 lines of code to complete. This means that even if you are new to code, you can easily connect to Uniswap V3 on FMZ and start trading immediately.

FMZ has encapsulated a series of web3 basic functions. Besides Uniswap, it can also encapsulate other DEX exchanges with few codes. Next, let me take you to learn the concepts and technologies in defi application from scratch. Due to the space, the following description is as simple as possible. It may not be very precise, but it is easy to understand.

Uniswap V3 Trade Template disclosed by FMZ platform

The code is as follows:

/* 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))
}

Ethereum network

Ethereum network can be understood as a software infrastructure, on which various smart contracts can be deployed and run. Smart contracts have various functions and application scenarios. The devices running the Ethereum client constitute the nodes in the Ethereum network.

Some concepts in Uniswap V3

Students who are not familiar with the Uniswap V3 protocol need to understand a few concepts first. Uniswap V3 is also a smart contract deployed and running on Ethereum.

  1. Route: Route is also a smart contract, which is used to manage the exchange of token.
  2. Pool: The pool is also a smart contract for storing two kinds of Ethereum tokens and exchanging between these two tokens.
  3. Factory contract: A factory contract is a smart contract used to create a pool.
  4. ABI: (Application Binary Interface) is a specification that describes how smart contracts communicate with the outside world. It specifies the function name, parameter type and return value type of the smart contract, how to encode and decode data, and determines the external interface of the smart contract. It can be understood that to call an interface, it must be called according to the agreed standards of the interface, and the ABI records a series of agreed standards.

Once the smart contract is deployed on Ethereum, there will be an address.

Analyze the code of Uniswap V3 Trade Template

The Uniswap V3 trading class library code is mainly divided into four parts, which we will explain one by one.

Part 1: Constants used when interacting with Uniswap V3

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

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

With the above basic concept preview, it’s easy to understand here.

ABI_Route The string stored by this constant is the ABI of the routing smart contract. ABI_Pool stores the ABI of the pool contract. ABI_Factory The ABI of the factory contract.

Since these strings are long, they are just excerpts. These contents provide a standard for the program to call the smart contract method (for example, what are the parameters of the smart contract interface, how many parameters, what type are they, and what type of returned data are).

As we mentioned just now, once the smart contract is deployed in Ethereum, there will be an address.

ContractV3Factory: The address of the factory contract is recorded. ContractV3SwapRouterV2: The router V2 address of Uniswap V3. Note that Uniswap has V1 and V2. The router of Uniswap V3 also has V1 and V2. Different contract addresses are different.

Part2: Tool functions

  1. computePoolPrice function is used to calculate the price of the token in the pool.
function computePoolPrice(decimals0, decimals1, sqrtPriceX96) {
    [decimals0, decimals1, sqrtPriceX96] = [decimals0, decimals1, sqrtPriceX96].map(BigInt);   // Use the BigInt function for processing. Because of the precision of JavaScript language values, it is necessary to use one of FMZ's underlying processing functions, BigInt, to process.
    const TWO = BigInt(2);     // Define constant 2 to calculate
    const TEN = BigInt(10);    // Define constant 10 to calculate
    const SIX_TENTH = BigInt(1000000);    // Define the 6th power of constant 10, i.e. 1e6
    const Q192 = (TWO ** BigInt(96)) ** TWO;  // 2^192
    return (
        Number((sqrtPriceX96 ** TWO * TEN ** decimals0 * SIX_TENTH) / (Q192 * TEN ** decimals1)) /
        Number(SIX_TENTH)
    );
}

If the trading pair is ETH_USDT, then token0 is ETH, and token1 is USDT. decimals0 is the precision data of token0, and decimals1 is the precision data of token1. SqrtPriceX96 is the price-related data (not the direct price value), which can be obtained from the slot0 method of the pool contract.

sqrtPriceX96 : The current price of the pool as a sqrt(token1/token0) Q64.96 value Q64.96 is a data processing and storage standard.

These three data decimals0, decimals1, sqrtPriceX96 are passed into the computePoolPrice function as parameters to calculate the price of the trading pair ETH_USDT. The algorithm in the last return statement of this function is the process of restoring sqrtPriceX96 to token1/token0. For example, the number of token0 (ETH) in the pool is 1, and the number of token1 (USDT) is 1100. So 1100/1=1100, the current price in the ETH_USDT pool is 1100.

  1. toAmount function is used to convert numeric data in the chain into readable data.
function toAmount(s, decimals) {
    return Number((BigDecimal(BigInt(s))/BigDecimal(Math.pow(10, decimals))).toString())
}

To put it simply, for example, an ETH token is 1e18 when the number is represented on the chain, i.e., the 18th power of 10, because the precision data of ETH is 18. Not all tokens have a precision of 18, and the precision of USDT is not the same as that of ETH. The toAmount function is to convert 1e18 to 1.

  1. The toInnerAmount function is the opposite of the toAmount function, which converts readable data into values used in the chain.
function toInnerAmount(n, decimals) {
    return (BigDecimal(n)*BigDecimal(Math.pow(10,decimals))).toFixed(0)
}

Next, let’s analyze the code of “Uniswap V3 Trade Template”.

Part3: Constructor of Uniswap V3 operation object

The core of this template class library is the Uniswap V3 operation object, which implements the basic operations on Uniswap V3. More functions may be upgraded in the future. By analyzing this code example, even if you do not use the FMZ platform, you will increase your knowledge and understanding of the processes and details of each link of Uniswap DEX. Now let’s learn how these basic functions are designed and implemented on FMZ.

Constructor code of Uniswap V3 operation object:

$.NewUniswapV3 = function(e) {
    e = e || exchange                          // If the parameter e is not passed, the exchange object exchange is used, that is, the first exchange added in the strategy.
    if (e.GetName() !== 'Web3') {              // Determine if the exchange object is Web3, because this template only supports Web3 exchange objects.
        panic("only support Web3 exchange")
    }


    let self = {                               // The current function is a constructor, and the constructed object is the object self.
        tokenInfo: {},                         // Member variable of the self object, used to record the registration information of the token.
        walletAddress: e.IO("address"),        // Record the address of the wallet to which the current exchange object is bound.
        pool: {}                               // Used to record registered pool information.
    }

    // register
    e.IO("abi", ContractV3Factory, ABI_Factory)       // ABI for registered factory contracts
    e.IO("abi", ContractV3SwapRouterV2, ABI_Route)    // ABI for registered routing contracts

    self.addToken = function(name, address) {         // Used to register token
        let ret = e.IO("api", address, "decimals")    // Call the decimals method to get token precision information
        if (!ret) {
            throw "get token decimals failed"
        }
        let decimals = Number(ret)
        self.tokenInfo[name] = {
            name: name,
            decimals: decimals,
            address: address
        }
    }
    self.waitMined = function(tx) {             // It is used to wait for the result of an operation on Ethereum. The hash is a tx parameter.
        while (true) {
            Sleep(1000)
            let info = e.IO("api", "eth", "eth_getTransactionReceipt", tx)  // Query results using eth_getTransactionReceipt method, if it's not found, loop to continue query.
            if (info && info.gasUsed) {
                return true
            }
            Log('Transaction not yet mined', tx)
        }
    }

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

        if (!tokenOutInfo) {
            throw "not found token info " + tokenOut
        }
        
        let amountIn = toInnerAmount(amountInDecimal, tokenInInfo.decimals)  // Convert to data used on smart contracts
        let recipientAddress = self.walletAddress
        if (tokenInInfo.name != 'ETH') {
            let allowanceAmount = e.IO("api", tokenInInfo.address, "allowance", self.walletAddress, ContractV3SwapRouterV2);   // Query the number of authorizations
            let realAmount = toAmount(allowanceAmount, tokenInInfo.decimals)
            if (realAmount < toAmount(amountIn, tokenInInfo.decimals)) {    // If the number of licenses is insufficient
                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 the authorized token is USDT, it needs to be authorized to 0 first.
                    if (!txApprove) {
                        throw "approve error"
                    }
                    Log("wait reduce approve", txApprove)
                    self.waitMined(txApprove)
                }

                let txApprove = e.IO("api", tokenInInfo.address, "approve", ContractV3SwapRouterV2, '0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff');  // Authorize Router contracts to operate the wallet's tokens
                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'
            // When exchanging other coins for WETH, you have to let
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