# Router The `UniswapV2Router02` contract facilitates interactions with the Uniswap decentralized exchange, including adding and removing liquidity, swapping tokens, and retrieving price quotes. It supports the following operations: * **Add Liquidity:** Allows users to contribute tokens to liquidity pools. * **Remove Liquidity:** Enables users to withdraw their tokens from liquidity pools. * **Token Swaps:** Facilitates swapping of tokens through Uniswap pairs. * **Supporting Fee-On-Transfer Tokens:** Handles tokens with transfer fees during liquidity removal and swaps. * **Price Quotes and Amounts:** Provides functions to compute price quotes and required token amounts for swaps. ### State Variables * `factory`: Address of the Uniswap V2 factory contract. * `WETH`: Address of the wrapped ETH (WETH) token contract. ### Set Functions in UniswapV2Router02 #### `addLiquidity` Adds liquidity to a pair of tokens. Parameters: * `address tokenA`: Address of token A. * `address tokenB`: Address of token B. * `uint amountADesired`: Desired amount of token A. * `uint amountBDesired`: Desired amount of token B. * `uint amountAMin`: Minimum amount of token A. * `uint amountBMin`: Minimum amount of token B. * `address to`: Address to receive liquidity tokens. * `uint deadline`: Timestamp after which the transaction will revert. #### `addLiquidityETH` Adds liquidity to a token-ETH pair. Parameters: * `address token`: Address of the token. * `uint amountTokenDesired`: Desired amount of the token. * `uint amountTokenMin`: Minimum amount of the token. * `uint amountETHMin`: Minimum amount of ETH. * `address to`: Address to receive liquidity tokens. * `uint deadline`: Timestamp after which the transaction will revert. #### `removeLiquidity` Removes liquidity from a pair of tokens. Parameters: * `address tokenA`: Address of token A. * `address tokenB`: Address of token B. * `uint liquidity`: Amount of liquidity tokens to remove. * `uint amountAMin`: Minimum amount of token A. * `uint amountBMin`: Minimum amount of token B. * `address to`: Address to receive tokens. * `uint deadline`: Timestamp after which the transaction will revert. #### `removeLiquidityETH` Removes liquidity from a token-ETH pair. Parameters: * `address token`: Address of the token. * `uint liquidity`: Amount of liquidity tokens to remove. * `uint amountTokenMin`: Minimum amount of the token. * `uint amountETHMin`: Minimum amount of ETH. * `address to`: Address to receive tokens. * `uint deadline`: Timestamp after which the transaction will revert. #### `removeLiquidityWithPermit` Removes liquidity from a pair of tokens using a permit. Parameters: * `address tokenA`: Address of token A. * `address tokenB`: Address of token B. * `uint liquidity`: Amount of liquidity tokens to remove. * `uint amountAMin`: Minimum amount of token A. * `uint amountBMin`: Minimum amount of token B. * `address to`: Address to receive tokens. * `uint deadline`: Timestamp after which the transaction will revert. * `bool approveMax`: Whether to approve the maximum amount. * `uint8 v`: V value of the permit signature. * `bytes32 r`: R value of the permit signature. * `bytes32 s`: S value of the permit signature. #### `removeLiquidityETHWithPermit` Removes liquidity from a token-ETH pair using a permit. Parameters: * `address token`: Address of the token. * `uint liquidity`: Amount of liquidity tokens to remove. * `uint amountTokenMin`: Minimum amount of the token. * `uint amountETHMin`: Minimum amount of ETH. * `address to`: Address to receive tokens. * `uint deadline`: Timestamp after which the transaction will revert. * `bool approveMax`: Whether to approve the maximum amount. * `uint8 v`: V value of the permit signature. * `bytes32 r`: R value of the permit signature. * `bytes32 s`: S value of the permit signature. #### `swapExactTokensForTokens` Swaps an exact amount of tokens for another token. Parameters: * `uint amountIn`: Amount of input tokens. * `uint amountOutMin`: Minimum amount of output tokens. * `address[] calldata path`: Array of token addresses to trade through. * `address to`: Address to receive output tokens. * `uint deadline`: Timestamp after which the transaction will revert. #### `swapTokensForExactTokens` Swaps tokens for an exact amount of another token. Parameters: * `uint amountOut`: Amount of output tokens. * `uint amountInMax`: Maximum amount of input tokens. * `address[] calldata path`: Array of token addresses to trade through. * `address to`: Address to receive output tokens. * `uint deadline`: Timestamp after which the transaction will revert. #### `swapExactETHForTokens` Swaps an exact amount of ETH for tokens. Parameters: * `uint amountOutMin`: Minimum amount of output tokens. * `address[] calldata path`: Array of token addresses to trade through. * `address to`: Address to receive output tokens. * `uint deadline`: Timestamp after which the transaction will revert. #### `swapTokensForExactETH` Swaps tokens for an exact amount of ETH. Parameters: * `uint amountOut`: Amount of output ETH. * `uint amountInMax`: Maximum amount of input tokens. * `address[] calldata path`: Array of token addresses to trade through. * `address to`: Address to receive ETH. * `uint deadline`: Timestamp after which the transaction will revert. #### `swapExactTokensForETH` Swaps an exact amount of tokens for ETH. Parameters: * `uint amountIn`: Amount of input tokens. * `uint amountOutMin`: Minimum amount of output ETH. * `address[] calldata path`: Array of token addresses to trade through. * `address to`: Address to receive ETH. * `uint deadline`: Timestamp after which the transaction will revert. #### `swapETHForExactTokens` Swaps ETH for an exact amount of tokens. Parameters: * `uint amountOut`: Amount of output tokens. * `address[] calldata path`: Array of token addresses to trade through. * `address to`: Address to receive output tokens. * `uint deadline`: Timestamp after which the transaction will revert. ### Read Functions #### `factory` Returns the address of the factory contract. Parameters: None Returns: * `address`: Address of the factory contract. Description: Retrieves the address of the factory contract used to create pairs of tokens. #### `WETH` Returns the address of the WETH token. Parameters: None Returns: * `address`: Address of the WETH token. Description: Retrieves the address of the Wrapped ETH (WETH) token used in the router. #### `quote` Calculates the amount of token B given an amount of token A and reserves. Parameters: * `uint amountA`: Amount of token A. * `uint reserveA`: Reserve amount of token A. * `uint reserveB`: Reserve amount of token B. Returns: * `uint amountB`: Amount of token B. Description: Computes the equivalent amount of token B given the amount of token A and their respective reserves. #### `getAmountOut` Calculates the maximum output amount of the other asset given an input amount and pair reserves. Parameters: * `uint amountIn`: Input amount of the asset. * `uint reserveIn`: Reserve amount of the input asset. * `uint reserveOut`: Reserve amount of the output asset. Returns: * `uint amountOut`: Output amount of the asset. Description: Determines the maximum output amount of the other asset given the input amount and the pair reserves. #### `getAmountIn` Calculates the required input amount of the other asset given an output amount and pair reserves. Parameters: * `uint amountOut`: Output amount of the asset. * `uint reserveIn`: Reserve amount of the input asset. * `uint reserveOut`: Reserve amount of the output asset. Returns: * `uint amountIn`: Input amount of the asset. Description: Computes the required input amount of the other asset given the output amount and the pair reserves. #### `getAmountsOut` Performs chained `getAmountOut` calculations on any number of pairs. Parameters: * `uint amountIn`: Input amount of the first asset. * `address[] memory path`: Array of token addresses to trade through. Returns: * `uint[] memory amounts`: Array of output amounts for each step in the path. Description: Executes a series of `getAmountOut` calculations along a specified path of token pairs. #### `getAmountsIn` Performs chained `getAmountIn` calculations on any number of pairs. Parameters: * `uint amountOut`: Output amount of the last asset. * `address[] memory path`: Array of token addresses to trade through. Returns: * `uint[] memory amounts`: Array of input amounts for each step in the path. Description: Executes a series of `getAmountIn` calculations along a specified path of token pairs. ### Events #### `PairCreated` Emitted when a new liquidity pair is created. * **Indexed Parameters**: * `address indexed token0`: The address of the first token in the pair. * `address indexed token1`: The address of the second token in the pair. * `address pair`: The address of the created pair. * **Non-Indexed Parameters**: * `uint`: The length of allPairs array after the pair is created. #### `Approval` Emitted when a token approval is made. * **Indexed Parameters**: * `address indexed owner`: The address of the token owner. * `address indexed spender`: The address of the spender. * **Non-Indexed Parameters**: * `uint value`: The amount of tokens approved. #### `Transfer` Emitted when a token transfer occurs. * **Indexed Parameters**: * `address indexed from`: The address of the sender. * `address indexed to`: The address of the recipient. * **Non-Indexed Parameters**: * `uint value`: The amount of tokens transferred. #### `Mint` Emitted when liquidity is added to a pool. * **Indexed Parameters**: * `address indexed sender`: The address that initiated the minting. * **Non-Indexed Parameters**: * `uint amount0`: The amount of token0 added. * `uint amount1`: The amount of token1 added. #### `Burn` Emitted when liquidity is removed from a pool. * **Indexed Parameters**: * `address indexed sender`: The address that initiated the burning. * `address indexed to`: The address that received the tokens. * **Non-Indexed Parameters**: * `uint amount0`: The amount of token0 removed. * `uint amount1`: The amount of token1 removed. #### `Swap` Emitted when a swap occurs in the pool. * **Indexed Parameters**: * `address indexed sender`: The address that initiated the swap. * `address indexed to`: The address that received the output tokens. * **Non-Indexed Parameters**: * `uint amount0In`: The amount of token0 input. * `uint amount1In`: The amount of token1 input. * `uint amount0Out`: The amount of token0 output. * `uint amount1Out`: The amount of token1 output. #### `Sync` Emitted when reserves are synced in the pool. * **Non-Indexed Parameters**: * `uint112 reserve0`: The reserve of token0. * `uint112 reserve1`: The reserve of token1. #### `Deposit` Emitted when ETH is deposited to the WETH contract. * **Indexed Parameters**: * `address indexed sender`: The address that deposited ETH. * **Non-Indexed Parameters**: * `uint value`: The amount of ETH deposited. #### `Withdraw` Emitted when ETH is withdrawn from the WETH contract. * **Indexed Parameters**: * `address indexed sender`: The address that withdrew ETH. * **Non-Indexed Parameters**: * `uint value`: The amount of ETH withdrawn.