# Swap

## Swap

Swaps typically occur in two steps:

* the first step involves pre-calculating the potential result of the current transaction；
* the second step is to set the slippage based on the pre-calculated results, followed by executing the transaction.

After pre-calcualting then you can do swap via:

* swap
* [partner swap](https://cetus-1.gitbook.io/cetus-developer-docs/developer/via-sdk/features-available/partner-swap)

## Swap after preswap

After pre-calcualting then swap. [For a more detailed understanding of the pre-swap process and its intricacies, additional information is available here.](https://cetus-1.gitbook.io/cetus-developer-docs/developer/via-sdk/features-available/preswap)

#### Function input param

*Please refer to the original function for specific parameter types.*

* **`poolID`**: pool object id, you can get it by pre-calcualting.
* **`coinTypeA`**: the coin type address about coinA.
* **`coinTypeB`**: the coin type address about coinB.
* **`a2b`**: swap direction, `true` means swap from coinA to coinB, `false` means swap from coinB to CoinA.
* **`byAmountIn`**: `true` means fixed the amount of input, `false` means fixed the amount of output.
* **`amount`**: the amount of input (`byAmountIn` = `true`) or output (`byAmountIn` = `false`).
* **`amountLimit`**: the amount limit of coin what you get. There are two scenarios in amount limit, when by\_amount\_in equals true, amount limit means minimum number of outputs required to be obtained, when by\_amount\_in equals false, it means maximum number of input coin.
* **`partner`**: The partner address. If you do not have a partner, simply leave the partner field unset.

  *Notice*:

  * This is the amount out of result after slippage adjustment. Use `adjustForSlippage` to calculate the limit of amount out.
  * If you set amount limit equal 0, when you trade during extremely volatile price fluctuations, you might end up with a very small trading outcome. The `amountLimit` will help prevent your assets from incurring losses.
  * You can get more details in these [Partner swap ](https://cetus-1.gitbook.io/cetus-developer-docs/developer/via-sdk/features-available/partner-swap)parts.

#### Example

<pre class="language-ts"><code class="lang-ts"><strong>import BN from 'bn.js'
</strong>import { adjustForSlippage, d, initCetusSDK, Percentage, TransactionUtil } from '@cetusprotocol/cetus-sui-clmm-sdk'

const sdk = initCetusSDK({ network: 'mainnet' })
const sendKeypair = buildTestAccount()
// Whether the swap direction is token a to token b
const a2b = true
// fix input token amount
const coinAmount = new BN(120000)
// slippage value
const slippage = Percentage.fromDecimal(d(5))
// Fetch pool data
const pool = await sdk.Pool.getPool(poolAddress)
// Estimated amountIn amountOut fee
const res: any = await sdk.Swap.preswap({
  pool: pool,
  current_sqrt_price: pool.current_sqrt_price,
  coinTypeA: pool.coinTypeA,
  coinTypeB: pool.coinTypeB,
  decimalsA: 6, // coin a 's decimals
  decimalsB: 8, // coin b 's decimals
  a2b,
  by_amount_in: true, // fix token a amount
  amount,
})

const partner = '0x8e0b7668a79592f70fbfb1ae0aebaf9e2019a7049783b9a4b6fe7c6ae038b528'

const toAmount = byAmountIn ? res.estimatedAmountOut : res.estimatedAmountIn
const amountLimit =  adjustForSlippage(toAmount, slippage, !byAmountIn)

// build swap Payload
const swapPayload = sdk.Swap.createSwapTransactionPayload(
  {
    pool_id: pool.poolAddress,
    coinTypeA: pool.coinTypeA,
    coinTypeB: pool.coinTypeB
    a2b: a2b,
    by_amount_in: by_amount_in,
    amount: res.amount.toString(),
    amount_limit: amountLimit.toString(),
    swap_partner: partner,
  },
)

const swapTxn = await sdk.fullClient.sendTransaction(signer, swapPayload)
</code></pre>

## Swap without transfer coins

This methods support return two coins for user to build PTB.

#### Function input param

*Please refer to the original function for specific parameter types.*

* **`poolID`**: pool object id, you can get it by pre-calcualting.
* **`coinTypeA`**: the coin type address about coinA.
* **`coinTypeB`**: the coin type address about coinB.
* **`a2b`**: swap direction, `true` means swap from coinA to coinB, `false` means swap from coinB to CoinA.
* **`byAmountIn`**: `true` means fixed the amount of input, `false` means fixed the amount of output.
* **`amount`**: the amount of input (`byAmountIn` = `true`) or output (`byAmountIn` = `false`).
* **`amountLimit`**: the amount limit of coin what you get. There are two scenarios in amount limit, when by\_amount\_in equals true, amount limit means minimum number of outputs required to be obtained, when by\_amount\_in equals false, it means maximum number of input coin.
* **`partner`**: The partner address. If you do not have a partner, simply leave the partner field unset.

  *Notice*:

  * This is the amount out of result after slippage adjustment. Use `adjustForSlippage` to calculate the limit of amount out.
  * If you set amount limit equal 0, when you trade during extremely volatile price fluctuations, you might end up with a very small trading outcome. The `amountLimit` will help prevent your assets from incurring losses.
  * You can get more details in these [Partner swap ](https://cetus-1.gitbook.io/cetus-developer-docs/developer/via-sdk/features-available/partner-swap)parts.

#### Example

```ts
import BN from 'bn.js'
import { adjustForSlippage, d, initCetusSDK, Percentage, TransactionUtil } from '@cetusprotocol/cetus-sui-clmm-sdk'

const sdk = initCetusSDK({ network: 'mainnet' })
const sendKeypair = buildTestAccount()
// Whether the swap direction is token a to token b
const a2b = true
// fix input token amount
const coinAmount = new BN(120000)
// input token amount is token a
const byAmountIn = true
// slippage value
const slippage = Percentage.fromDecimal(d(5))
// Fetch pool data
const pool = await sdk.Pool.getPool(poolAddress)
// Estimated amountIn amountOut fee
const res: any = await sdk.Swap.preswap({
  pool: pool,
  current_sqrt_price: pool.current_sqrt_price,
  coinTypeA: pool.coinTypeA,
  coinTypeB: pool.coinTypeB,
  decimalsA: 6, // coin a 's decimals
  decimalsB: 8, // coin b 's decimals
  a2b,
  by_amount_in,
  amount,
})

const partner = '0x8e0b7668a79592f70fbfb1ae0aebaf9e2019a7049783b9a4b6fe7c6ae038b528'

const toAmount = byAmountIn ? res.estimatedAmountOut : res.estimatedAmountIn
const amountLimit =  adjustForSlippage(toAmount, slippage, !byAmountIn)

// build swap Tx
const {swapTx, coinsAB} = sdk.Swap.createSwapTransactionWithoutTransferCoinsPayload(
  {
    pool_id: pool.poolAddress,
    coinTypeA: pool.coinTypeA,
    coinTypeB: pool.coinTypeB
    a2b: a2b,
    by_amount_in: by_amount_in,
    amount: res.amount.toString(),
    amount_limit: amountLimit.toString(),
    swap_partner: partner,
  },
)
// transfer coin a and coin b
 swapTx.transferObjects(coins, tx.pure.address(recipient))

const transferTxn = await sdk.fullClient.sendTransaction(signer,swapPayload)
console.log('swap: ', transferTxn)
```