Pre Swap

Before performing an actual swap, you can do a pre-swap to get the swap result. Then you can set amount limit by swap result and slippage.

This text describes two primary methods for performing a swap function, each with distinct steps and calculation methods:

1. The first method involves initially obtaining tick data, followed by performing calculations locally

2. The second method involves conducting a simulated swap and then obtaining the resultant data through an event on Sui

There are three pre-calculation strategies for executing a swap:

1. Local Calculate

2. Simulate swap then get result

   • Single pool swap result: use sdk.Swap.preSwap()

   • Multi pool calculation: use sdk.Swap.preSwapWithMultiPool()

Local Calculate Swap Result

This method requires getting ticks data and pool object first using sdk.Swap.calculateRates method.

Function Parameters

• params: CalculateRatesParams object

• decimals_a: the decimal of coinA

• decimals_b: the decimal of coinB

• a2b: swap direction, true means swap from coinA to coinB, false means swap from coinB to CoinA

• by_amount_in: true means fixed the amount of input, false means fixed the amount of output

• amount: the amount of input (by_amount_in = true) or output (by_amount_in = false)

• swap_ticks: the array of TickData, get them by sdk.Pool.fetchTicks()

• current_pool: the pool object, get it by sdk.Pool.getPool()

Example

const a2b = false
const pool = await sdk.Pool.getPool('0xc8d7a1503dc2f9f5b05449a87d8733593e2f0f3e7bffd90541252782e4d2ca20')
const by_amount_in = false
const amount = '80000000000000'

const swap_ticks = await sdk.Pool.fetchTicks({
  pool_id: pool.id,
  coin_type_a: pool.coin_type_a,
  coin_type_b: pool.coin_type_b,
})
// or
// const swapTicks =  await  sdk.Pool.fetchTicksByRpc(pool.ticks_handle)

const res = sdk.Swap.calculateRates({
  decimals_a: 6,
  decimals_b: 6,
  a2b,
  by_amount_in,
  amount: new BN(amount),
  swap_ticks,
  current_pool: pool,
})

PreSwap by Simulation Transaction

preSwap

Use sdk.Swap.preSwap method.

Function Parameters

• pool: pool object, you can get it by sdk.Pool.getPool() method

• current_sqrt_price: pool's current_sqrt_price

• coin_type_a: the coin type address about coinA

• coin_type_b: the coin type address about coinB

• decimals_a: the decimal of coinA

• decimals_b: the decimal of coinB

• a2b: swap direction, true means swap from coinA to coinB, false means swap from coinB to CoinA

• by_amount_in: true means fixed the amount of input, false means fixed the amount of output

• amount: the amount of input (by_amount_in = true) or output (by_amount_in = false)

Example

const a2b = true
const by_amount_in = true
const amount = '10000000'
const slippage = Percentage.fromDecimal(d(0.1))

const pool = await sdk.Pool.getPool('0x6fd4915e6d8d3e2ba6d81787046eb948ae36fdfc75dad2e24f0d4aaa2417a416')

const res = await sdk.Swap.preSwap({
  pool,
  current_sqrt_price: : pool.current_sqrt_price,
  coin_type_a: pool.coin_type_a,
  coin_type_b: pool.coin_type_b,
  decimals_a: 6,
  decimals_b: 6,
  a2b,
  by_amount_in,
  amount,
})

preSwapWithMultiPool

Use sdk.Swap.preSwapWithMultiPool() method.

Function Parameters

• pool_ids: An array of pool objects ID. All pools must have the same type

• coin_type_a: the coin type address about coinA

• coin_type_b: the coin type address about coinB

• a2b: swap direction, true means swap from coinA to coinB, false means swap from coinB to CoinA

• by_amount_in: true means fixed the amount of input, false means fixed the amount of output

• amount: the amount of input (by_amount_in = true) or output (by_amount_in = false)

Example

const a2b = true
const pool_ids = [
  '0x53d70570db4f4d8ebc20aa1b67dc6f5d061d318d371e5de50ff64525d7dd5bca',
  '0x4038aea2341070550e9c1f723315624c539788d0ca9212dca7eb4b36147c0fcb',
  '0x6fd4915e6d8d3e2ba6d81787046eb948ae36fdfc75dad2e24f0d4aaa2417a416',
]
const pool0 = await sdk.Pool.getPool(pool_ids[0])
const pool1 = await sdk.Pool.getPool(pool_ids[1])
const pool2 = await sdk.Pool.getPool(pool_ids[2])
const by_amount_in = true
const amount = '10000000'

const res_with_multi_pool = await sdk.Swap.preSwapWithMultiPool({
  pool_ids: pool_ids,
  coin_type_a: pool0.coin_type_a,
  coin_type_b: pool0.coin_type_b,
  a2b,
  by_amount_in,
  amount,
})