Switch Adapters

These switch adapters integrate Nexus' Flash Loans and the ParaSwap DEX aggregator smart contracts to facilitate advanced actions such as repaying borrow positions using collateral, switching collateral assets, switching borrow positions, and withdrawing and switching assets. They allow users to perform complex operations in a single transaction, leveraging the liquidity of the Nexus protocol and the atomic switching capabilities of decentralized exchanges.

Market	Repay With Collateral	Collateral Switch	Debt Switch	Withdraw & Switch
Ethereum Sepolia	✔️	✔️	✔️	✔️
Base Sepolia	✔️	✔️	✔️	✔️
BSC Chapel	✔️	✔️	✔️	✔️

Repay With Collateral

The ParaSwapRepayAdapter contract enables users to repay their borrow positions on Nexus using their supplied collateral directly, without the need to unwind their positions or provide additional liquidity. It leverages Nexus' Flash Loans and the ParaSwap DEX aggregator to switch the user's collateral for the borrowed asset and repay the borrow position in a single atomic transaction.

By using this adapter, users can efficiently manage their positions and reduce their borrow positions using their existing collateral, saving on transaction costs and avoiding manual steps.

The source code is available on GitHub.

Reference Integration: useCollateralRepaySwap.tsx

Write Methods

executeOperation

function executeOperation(
    address asset,
    uint256 amount,
    uint256 premium,
    address initiator,
    bytes calldata params
) external override nonReentrant returns (bool)

Uses the received funds from the flash loan to repay a borrow position on the protocol on behalf of the user. Then, pulls the collateral from the user and switches it to the debt asset to repay the flash loan.

The user should give this contract allowance to pull the zTokens in order to withdraw the underlying asset, switch it, and repay the flash loan.

Supports only one asset on the flash loan.

The params parameter should be the ABI-encoded values of the following:

• IERC20Detailed debtAsset — The address of the borrow position asset

• uint256 debtRepayAmount — The amount of the borrow position to be repaid

• uint256 buyAllBalanceOffset — Offset in the ParaSwap calldata if switching all balance

• uint256 rateMode — The rate mode of the borrow position to be repaid

• bytes paraswapData — Data for the ParaSwap Adapter

• PermitSignature permitSignature — Struct containing the permit signature, set to zeroes if not used

Input Parameters:

Name	Type	Description
asset	address	The address of the flash-borrowed asset
amount	uint256	The amount of the flash-borrowed asset
premium	uint256	The fee of the flash-borrowed asset
initiator	address	The address of the flash loan initiator
params	bytes	The byte-encoded parameters passed when initiating the flash loan

Return Values:

Type	Description
bool	True if the execution of the operation succeeds, false otherwise

swapAndRepay

function swapAndRepay(
    IERC20Detailed collateralAsset,
    IERC20Detailed debtAsset,
    uint256 collateralAmount,
    uint256 debtRepayAmount,
    uint256 debtRateMode,
    uint256 buyAllBalanceOffset,
    bytes calldata paraswapData,
    PermitSignature calldata permitSignature
) external nonReentrant

Switches the user's collateral for the debt asset and then repays the borrow position on the protocol on behalf of the user without using flash loans. This method can be used when the temporary transfer of the collateral asset to this contract does not affect the user's position.

The user should give this contract allowance to pull the zTokens in order to withdraw the underlying asset.

Input Parameters:

Name	Type	Description
collateralAsset	IERC20Detailed	The address of the collateral asset to be switched
debtAsset	IERC20Detailed	The address of the debt asset
collateralAmount	uint256	The maximum amount of the collateral to be switched
debtRepayAmount	uint256	The amount of the borrow position to be repaid, or maximum amount when repaying all
debtRateMode	uint256	The rate mode of the borrow position to be repaid
buyAllBalanceOffset	uint256	Offset in the ParaSwap calldata if switching all balance, otherwise 0
paraswapData	bytes	Data for the ParaSwap Adapter
permitSignature	PermitSignature	Struct containing the permit signature, set to zeroes if not used

PermitSignature Struct

struct PermitSignature {
    uint256 deadline;
    uint8 v;
    bytes32 r;
    bytes32 s;
}

Members:

Name	Type	Description
deadline	uint256	The deadline timestamp for the permit signature
v	uint8	The V parameter of the ECDSA signature
r	bytes32	The R parameter of the ECDSA signature
s	bytes32	The S parameter of the ECDSA signature

---

Collateral Switch

The ParaSwapLiquiditySwapAdapter contract allows users to switch their supplied collateral from one asset to another in a single transaction using Nexus' Flash Loans and the ParaSwap DEX aggregator.

This adapter enables users to rebalance their collateral positions without needing to withdraw and re-supply assets manually. By leveraging flash loans, the user can switch their existing collateral to a new asset and supply it back into the Nexus protocol in a single transaction.

The source code is available on GitHub.

Reference Integration: useCollateralSwap.tsx

Write Methods

executeOperation

function executeOperation(
    address asset,
    uint256 amount,
    uint256 premium,
    address initiator,
    bytes calldata params
) external override nonReentrant returns (bool)

Switches the received amount from the flash loan into the specified asset. The received funds from the switch are then supplied into the protocol on behalf of the user.

The user should give this contract allowance to pull the zTokens in order to withdraw the underlying asset and repay the flash loan.

The params parameter should be the ABI-encoded values of the following:

• IERC20Detailed assetToSwapTo — The address of the underlying asset to be switched to and supplied

• uint256 minAmountToReceive — The minimum amount to be received from the switch

• uint256 swapAllBalanceOffset — Offset in the Augustus calldata if switching all balance, otherwise 0

• bytes swapCalldata — Calldata for ParaSwap's Augustus Swapper contract

• IParaSwapAugustus augustus — Address of ParaSwap's Augustus Swapper contract

• PermitSignature permitParams — Struct containing the permit signature, set to zeroes if not used

Input Parameters:

Name	Type	Description
asset	address	The address of the flash-borrowed asset
amount	uint256	The amount of the flash-borrowed asset
premium	uint256	The fee of the flash-borrowed asset
initiator	address	The address of the flash loan initiator
params	bytes	The byte-encoded parameters passed when initiating the flash loan

Return Values:

Type	Description
bool	True if the execution of the operation succeeds, false otherwise

swapAndDeposit

function swapAndDeposit(
    IERC20Detailed assetToSwapFrom,
    IERC20Detailed assetToSwapTo,
    uint256 amountToSwap,
    uint256 minAmountToReceive,
    uint256 swapAllBalanceOffset,
    bytes calldata swapCalldata,
    IParaSwapAugustus augustus,
    PermitSignature calldata permitParams
) external nonReentrant

Switches an amount of an asset to another and supplies the new asset amount on behalf of the user without using a flash loan. This method can be used when the temporary transfer of the collateral asset to this contract does not affect the user's position.

The user should give this contract allowance to pull the zTokens in order to withdraw the underlying asset and perform the switch.

Input Parameters:

Name	Type	Description
assetToSwapFrom	IERC20Detailed	The address of the underlying asset to be switched from
assetToSwapTo	IERC20Detailed	The address of the underlying asset to be switched to and supplied
amountToSwap	uint256	Amount to be switched, or maximum amount when switching all balance
minAmountToReceive	uint256	Minimum amount to be received from the switch
swapAllBalanceOffset	uint256	Offset in Augustus calldata if switching all balance, otherwise 0
swapCalldata	bytes	Calldata for ParaSwap's Augustus Swapper contract
augustus	IParaSwapAugustus	Address of ParaSwap's Augustus Swapper contract
permitParams	PermitSignature	Struct containing the permit signature, set to zeroes if not used

---

Withdraw & Switch

The ParaSwapWithdrawSwapAdapter contract allows users to withdraw their supplied assets from Nexus and switch them to another asset in a single transaction using the ParaSwap DEX aggregator.

This adapter enables users to efficiently exit positions and switch their assets without having to perform multiple transactions, reducing gas costs and simplifying the user experience.

The source code is available on GitHub.

Reference Integration: WithdrawAndSwitchActions.tsx

Write Methods

withdrawAndSwap

function withdrawAndSwap(
    IERC20Detailed assetToSwapFrom,
    IERC20Detailed assetToSwapTo,
    uint256 amountToSwap,
    uint256 minAmountToReceive,
    uint256 swapAllBalanceOffset,
    bytes calldata swapCalldata,
    IParaSwapAugustus augustus,
    PermitSignature calldata permitParams
) external nonReentrant

Switches an amount of an asset to another after a withdrawal and transfers the new asset to the user. The user should give this contract allowance to pull the zTokens in order to withdraw the underlying asset and perform the switch.

Input Parameters:

Name	Type	Description
assetToSwapFrom	IERC20Detailed	The address of the underlying asset to be switched from
assetToSwapTo	IERC20Detailed	The address of the underlying asset to be switched to
amountToSwap	uint256	Amount to be switched, or maximum amount when switching all balance
minAmountToReceive	uint256	Minimum amount to be received from the switch
swapAllBalanceOffset	uint256	Offset in Augustus calldata if switching all balance, otherwise 0
swapCalldata	bytes	Calldata for ParaSwap's Augustus Swapper contract
augustus	IParaSwapAugustus	Address of ParaSwap's Augustus Swapper contract
permitParams	PermitSignature	Struct containing the permit signature, set to zeroes if not used

executeOperation

Note that in this contract, the executeOperation method is overridden but simply reverts with NOT_SUPPORTED, so it's not intended to be used.