Making a Swap

All of the Flaunch liquidity is powered by Uniswap V4, meaning that swaps can be easily executed using the Uniswap V4 Universal Router.

All liquidity on Flaunch is created as FLETH : MEME, meaning that to make a swap between ETH and Token, we will need an intermediary step to either wrap or unwrap ETH <> FLETH.

Swapping ETH to / from Token

In the following example we make a 2-step swap to convert ETH to FLETH to MEME.

Note that code has not been tested and is provided as-is, as a learning resource, and should not be used in production without proper audits and review.

// Encode the Universal Router command
bytes memory commands = abi.encodePacked(uint8(Commands.V4_SWAP));
bytes[] memory inputs = new bytes[](1);

// Encode V4Router actions
bytes memory actions = abi.encodePacked(
    uint8(Actions.SWAP_EXACT_IN_SINGLE),
    uint8(Actions.SWAP_EXACT_IN_SINGLE),
    uint8(Actions.SETTLE_ALL),
    uint8(Actions.TAKE_ALL)
);

// Set the amount being spent
int amountIn = -1e18;

// Set the minimum amount of tokens to receive
uint minAmountOut = 0;

// Set an optional referrer address
address referrer = address(0);

// Define the PoolKey for ETH/FLETH
PoolKey memory ethPoolKey = PoolKey({
    currency0: ETH_ADDRESS,
    currency1: FLETH_ADDRESS,
    fee: 0,
    tickSpacing: 60,
    hooks: IHooks(POOL_MANAGER_HOOK_ADDRESS)
});

// Define the PoolKey for FLETH/MEME
PoolKey memory memePoolKey = PoolKey({
    currency0: FLETH_ADDRESS,
    currency1: TOKEN,
    fee: 0,
    tickSpacing: 60,
    hooks: IHooks(POSITION_MANAGER_HOOK_ADDRESS)
});

// Prepare parameters for each action
bytes[] memory params = new bytes[](4);

// Param: Swapping ETH to FLETH
params[0] = abi.encode(
    IV4Router.ExactInputSingleParams({
        poolKey: ethPoolKey,
        zeroForOne: true,
        amountIn: amountIn,
        amountOutMinimum: minAmountOut,
        sqrtPriceLimitX96: TickMath.MAX_TICK - 1,
        hookData: bytes('')
    })
);

// Param: Swapping FLETH to MEME
params[1] = abi.encode(
    IV4Router.ExactInputSingleParams({
        poolKey: key,
        zeroForOne: true,
        amountIn: amountIn,
        amountOutMinimum: minAmountOut,
        sqrtPriceLimitX96: TickMath.MAX_TICK - 1,
        hookData: abi.encode(referrer)
    })
);

// Param: Settling spent ETH
params[2] = abi.encode(key.currency0, amountIn);

// Param: Confirming expected min MEME received
params[3] = abi.encode(key.currency1, minAmountOut);

// Combine actions and params into inputs
inputs[0] = abi.encode(actions, params);

// Execute the swap
router.execute(commands, inputs, block.timestamp);