NonfungiblePositionManager

Variables

struct Position {
    uint96 nonce;
    address operator;
    uint80 poolId;
    int24 tickLower;
    int24 tickUpper;
    uint128 liquidity;
    uint256 feeGrowthInside0LastX128;
    uint256 feeGrowthInside1LastX128;
    uint128 tokensOwed0;
    uint128 tokensOwed1;
}

Description: Details about a specific NFT position within the pool. Each Position struct holds essential information about the liquidity, fee growth, and tokens owed.

Functions

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function positions(uint256 tokenId) external view returns (
    uint96 nonce,
    address operator,
    address token0,
    address token1,
    uint24 fee,
    int24 tickLower,
    int24 tickUpper,
    uint128 liquidity,
    uint256 feeGrowthInside0LastX128,
    uint256 feeGrowthInside1LastX128,
    uint128 tokensOwed0,
    uint128 tokensOwed1
)

Description: Retrieves comprehensive details about a specific NFT position.

Parameters

Name	Type	Description
tokenId	uint256	The ID of the NFT position.

Return Values

Name	Type	Description
nonce	uint96	The nonce for permits.
operator	address	The address approved to manage this position.
token0	address	The first token of the pool.
token1	address	The second token of the pool.
fee	uint24	The fee tier of the pool.
tickLower	int24	The lower tick of the position's range.
tickUpper	int24	The upper tick of the position's range.
liquidity	uint128	The liquidity of the position.
feeGrowthInside0LastX128	uint256	The last recorded fee growth for token0 inside the range.
feeGrowthInside1LastX128	uint256	The last recorded fee growth for token1 inside the range.
tokensOwed0	uint128	The amount of token0 owed to the position.
tokensOwed1	uint128	The amount of token1 owed to the position.

---

function mint(MintParams calldata params) external payable returns (
    uint256 tokenId,
    uint128 liquidity,
    uint256 amount0,
    uint256 amount1
)

Description: Creates a new NFT position by adding liquidity to a specified pool and tick range.

Parameters

Name	Type	Description
params	MintParams	The parameters for minting the position (details below).

MintParams Struct Definition:

struct MintParams {
    address token0;
    address token1;
    uint24 fee;
    address recipient;
    int24 tickLower;
    int24 tickUpper;
    uint256 amount0Desired;
    uint256 amount1Desired;
    uint256 amount0Min;
    uint256 amount1Min;
    uint256 deadline;
}

Return Values

Name	Type	Description
tokenId	uint256	The ID of the newly minted NFT position.
liquidity	uint128	The amount of liquidity added to the position.
amount0	uint256	The actual amount of token0 used to mint the position. Matches the value from the callback.
amount1	uint256	The actual amount of token1 used to mint the position. Matches the value from the callback.

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modifier isAuthorizedForToken(uint256 tokenId)

Description: Ensures that the caller is either the owner or an approved operator for the specified NFT token ID.

---

function tokenURI(uint256 tokenId) public view returns (string memory)

Description: Returns the metadata URI for a given NFT position. Utilizes the token descriptor contract to generate the URI.

Parameters

Name	Type	Description
tokenId	uint256	The ID of the NFT position.

Return Values

Name	Type	Description
URI	string memory	The metadata URI for the specified token.

---

function baseURI() public pure returns (string memory)

Description: Returns the base URI for the NFT metadata. Note: Implementation is empty to save bytecode as it's unused.

---

function increaseLiquidity(IncreaseLiquidityParams calldata params) external payable returns (
    uint128 liquidity,
    uint256 amount0,
    uint256 amount1
)

Description: Increases the liquidity of an existing NFT position within its tick range.

Parameters

Name	Type	Description
params	IncreaseLiquidityParams	The parameters for increasing liquidity (details below).

IncreaseLiquidityParams Struct Definition:

struct IncreaseLiquidityParams {
    uint256 tokenId;
    uint256 amount0Desired;
    uint256 amount1Desired;
    uint256 amount0Min;
    uint256 amount1Min;
    uint256 deadline;
}

Return Values

Name	Type	Description
liquidity	uint128	The additional liquidity added to the position.
amount0	uint256	The actual amount of token0 added.
amount1	uint256	The actual amount of token1 added.

---

function decreaseLiquidity(DecreaseLiquidityParams calldata params) external payable returns (
    uint256 amount0,
    uint256 amount1
)

Description: Decreases the liquidity of an existing NFT position within its tick range.

Parameters

Name	Type	Description
params	DecreaseLiquidityParams	The parameters for decreasing liquidity (details below).

DecreaseLiquidityParams Struct Definition:

struct DecreaseLiquidityParams {
    uint256 tokenId;
    uint128 liquidity;
    uint256 amount0Min;
    uint256 amount1Min;
    uint256 deadline;
}

Return Values

Name	Type	Description
amount0	uint256	The amount of token0 withdrawn from the position.
amount1	uint256	The amount of token1 withdrawn from the position.

---

function collect(CollectParams calldata params) external payable returns (uint256 amount0, uint256 amount1)

Description: Collects tokens owed to an NFT position, including accumulated fees.

Parameters

Name	Type	Description
params	CollectParams	The parameters for collecting tokens (details below).

CollectParams Struct Definition:

struct CollectParams {
    uint256 tokenId;
    address recipient;
    uint128 amount0Max;
    uint128 amount1Max;
}

Return Values

Name	Type	Description
amount0	uint256	The amount of token0 collected.
amount1	uint256	The amount of token1 collected.

---

function burn(uint256 tokenId) external payable

Description: Burns an NFT position. The position must have zero liquidity and no tokens owed.

Parameters

Name	Type	Description
tokenId	uint256	The ID of the NFT position to burn.

---

function _getAndIncrementNonce(uint256 tokenId) internal returns (uint256)

Description: Retrieves and increments the nonce for a specific NFT position. Used internally for permit functionality.

Parameters

Name	Type	Description
tokenId	uint256	The ID of the NFT position.

Return Values

Name	Type	Description
nonce	uint256	The current nonce value.

---

function getApproved(uint256 tokenId) public view returns (address)

Description: Overrides the ERC721 getApproved function to return the operator approved for a specific NFT position.

Parameters

Name	Type	Description
tokenId	uint256	The ID of the NFT position.

Return Values

Name	Type	Description
operator	address	The address approved to manage the token.

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Modifiers

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modifier isAuthorizedForToken(uint256 tokenId)

Description: Ensures that the caller is either the owner or an approved operator for the specified NFT token ID.

Parameters

Name	Type	Description
tokenId	uint256	The ID of the NFT position.

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Events

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event IncreaseLiquidity(uint256 indexed tokenId, uint128 liquidity, uint256 amount0, uint256 amount1)

Description: Emitted when liquidity is added to an existing NFT position.

Parameters

Name	Type	Description
tokenId	uint256	The ID of the NFT position.
liquidity	uint128	The amount of liquidity added.
amount0	uint256	The amount of token0 added.
amount1	uint256	The amount of token1 added.

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event Collect(uint256 indexed tokenId, address recipient, uint256 amount0, uint256 amount1)

Description: Emitted when tokens are collected from an NFT position.

Parameters

Name	Type	Description
tokenId	uint256	The ID of the NFT position.
recipient	address	The address receiving the collected tokens.
amount0	uint256	The amount of token0 collected.
amount1	uint256	The amount of token1 collected.

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event DecreaseLiquidity(uint256 indexed tokenId, uint128 liquidity, uint256 amount0, uint256 amount1)

Description: Emitted when liquidity is removed from an NFT position.

Parameters

Name	Type	Description
tokenId	uint256	The ID of the NFT position.
liquidity	uint128	The amount of liquidity removed.
amount0	uint256	The amount of token0 withdrawn.
amount1	uint256	The amount of token1 withdrawn.

---

Usage Notes

1. Minting a New Position

   • Function: mint()

   • Description: Creates a new NFT representing a liquidity position within a specific pool and tick range.

   • Steps:

     1. Define the desired token pair (token0, token1) and fee tier.

     2. Specify the tick range (tickLower, tickUpper).

     3. Provide the desired amounts of token0 and token1 to add as liquidity.

     4. Call mint() with the appropriate parameters.

     5. Receive an NFT (tokenId) representing the position.

2. Increasing Liquidity

   • Function: increaseLiquidity()

   • Description: Adds additional liquidity to an existing NFT position.

   • Requirements:

     • The caller must be the owner or an approved operator of the NFT.

     • The specified liquidity must be added within the existing tick range.

3. Decreasing Liquidity

   • Function: decreaseLiquidity()

   • Description: Removes liquidity from an existing NFT position.

   • Requirements:

     • The caller must be the owner or an approved operator of the NFT.

     • The amount of liquidity to remove must not exceed the current liquidity of the position.

     • Tokens withdrawn are subject to slippage checks based on amount0Min and amount1Min.

4. Collecting Fees

   • Function: collect()

   • Description: Harvests accumulated fees from an NFT position.

   • Requirements:

     • The caller must be the owner or an approved operator of the NFT.

     • At least one of amount0Max or amount1Max must be greater than zero.

   • Notes:

     • Fees are collected in proportion to the liquidity provided.

     • Collected tokens can be sent to the NFT position manager or a specified recipient.

5. Burning a Position

   • Function: burn()

   • Description: Destroys an NFT representing a liquidity position.

   • Requirements:

     • The position must have zero liquidity and no tokens owed.

     • The caller must be the owner or an approved operator of the NFT.

6. Retrieving Position Details

   • Function: positions()

   • Description: Fetches detailed information about a specific NFT position.

   • Usage:

     • Useful for front-end applications or analytics to display position metrics.

7. Metadata URI

   • Function: tokenURI()

   • Description: Provides the metadata URI for a given NFT, which includes information like position details and visual representations.

   • Usage:

     • Integrates with NFT marketplaces and wallets to display position information.