Remove liquidity (zap out)

Function

To withdraw liquidity from a position and receive the funds as a single asset (a "zap out" transaction), use the remove_liquidity_single function in the router_v3 module.

This function simplifies the withdrawal process. It takes your liquidity position (composed of two assets), removes it from the pool, and automatically swaps one of the assets for the other, so you receive the entire value in a single, specified token.

public entry fun remove_liquidity_single(
    lp: &signer,
    lp_object: Object<position_v3::Info>,
    liquidity_delta: u128,
    to_meta: Object<Metadata>,
    slippage_numerators: u256,
    slippage_denominator: u256
) {
    // ... function body ...
}

Parameters

Parameter	Type	Description
lp	&signer	The signer of the transaction, representing the liquidity provider who owns the position.
lp_object	Object<position_v3::Info>	The liquidity position object from which you are withdrawing.
liquidity_delta	u128	The amount of liquidity units to remove. This is not a token amount but an abstract u128 value representing your share in the pool. To withdraw everything, use the full liquidity value from your lp_object.
to_meta	Object<Metadata>	The metadata of the single token you wish to receive as output. For example, if your position is APT/USDT, you can specify the USDT metadata here to receive all your funds in USDT.
slippage_numerators	u256	The numerator for calculating slippage tolerance on the internal swap required to consolidate your assets. For a 1% slippage, this would be 99.
slippage_denominator	u256	The denominator for calculating slippage tolerance, typically 100. This protects you from unfavorable price changes during the internal swap.

Detailed Parameter Explanation

Liquidity Delta (liquidity_delta)

This is the most critical parameter to understand correctly.

• What it is: liquidity_delta represents the "amount of liquidity" you want to remove, which is an abstract unit calculated by the protocol. It is not an amount of Token A or Token B.

• How to get it: You typically read the current liquidity value from your lp_object . If you want to withdraw all your funds, you would pass this full value as the liquidity_delta. If you only want to withdraw a portion (e.g., 50%), you would pass half of that value.

Slippage Tolerance (slippage_numerators / slippage_denominator)

This setting is crucial because the function performs an internal swap.

• Example: Imagine your position is in a APT/USDT pool. When you call this function and set to_meta to be USDT's metadata, the function does the following:

  1. Removes your proportional share of APT and USDT from the pool.

  2. Internally swaps the APT portion for USDT.

  3. Sends you the total amount of USDT.

• Meaning: The slippage tolerance applies to step 2. Setting slippage_numerators to 99 and slippage_denominator to 100 means you are willing to accept up to 1% negative slippage on the APT-to-USDT swap. If the price impact is worse than that, the transaction will fail, protecting your funds.