Version: 3.0.0

Constructing the calldata for adding liquidity uses the same function call to addCallParameters, which takes in a Position and an options field of type AddLiquidityOptions. Since the goal of this example is to add liquidity to an already existing position, construct IncreaseOptions instead of MintOptions. IncreaseOptions types are defined by the interfaces CommonAddLiquidityOptions and IncreaseSpecificOptions.
export interface CommonAddLiquidityOptions {  /**   * How much the pool price is allowed to move.   */  slippageTolerance: Percent  /**   * When the transaction expires, in epoch seconds.   */  deadline: BigintIsh  /**   * Whether to spend ether. If true, one of the pool tokens must be WETH, by default false   */  useNative?: NativeCurrency  /**   * The optional permit parameters for spending token0   */  token0Permit?: PermitOptions  /**   * The optional permit parameters for spending token1   */  token1Permit?: PermitOptions}export interface IncreaseSpecificOptions {  /**   * Indicates the ID of the position to increase liquidity for.   */  tokenId: BigintIsh}
To construct the IncreaseOptions struct, specify slippageTolerance, deadline, and tokenId. The tokenId is the unique identifier of the position (or more specifically, the ERC721 that represents a position). In this example, the tokenId is naively set to 1, but in production, each tokenId is unique and can be fetched on chain.
Use the functions tokensByIndex or tokenOfOwnerByIndex to fetch tokenIds for ERC721s.
const { calldata, value } = NonfungiblePositionManager.addCallParameters(position, {  slippageTolerance: new Percent(50, 10_000),  deadline: deadline,  tokenId: 1,})