Swap Contracts

Steps to add a new trading pair

1. Deploy a new LP token manually

with the following constructor parameters:

• swap: The SWAP contract address
• name: "Nebulas Liquidity Provider Token"
• symbol: "NLP" or anything else, for example "NLP_NAS_NAX"
• decimals: 8 is suggested

2. Call createPair with the following parameters:

• token0: The contract address of the first token.
• token1: The contract address of the second token.
• lp: The contract address of the deployed LP token.

Adding Liquidity

1. swap.addLiquidity, is for adding liquidity on two NRC20 tokens.

• tokenA: The contract address of the first token.
• tokenB: The contract address of the second token.
• amountADesired: The desired amount of the first token.
• amountBDesired: The desired amount of the second token.
• amountAMin: Minimum amount of the first token to add. amountAMin = amountADesired * (1 - slippage). The tx will fail is actually amount is less then it.
• amountBMin: Minimum amount of the second token to add.
• toAddress: LP token will be sent to this address.

2. swap.addLiquidityNAS, is the same as the above expect one NRC20 token is replaced by NAS.

• token: The contract address of the NRC20 token.
• amountTokenDesired: The desired amount of the NRC20 token.
• amountTokenMin: Minimum amount of the NRC20 token to add.
• amountNASMin: Minimum amount of NAS to add.
• toAddress: LP token will be sent to this address.

The sender of the TX also needs to send the desired amount of NAS.

Remove liquidity

1. swap.removeLiquidity

• tokenA: The contract address of the first token.
• tokenB: The contract address of the second token.
• liquidity: The amount of LP token to burn.
• amountAMin: Minimum amount of the first token to receive. amountAMin = liquidity / supplyOfLP * reserveOfTokenAInPair * (1 - slippage). The tx will fail is actually amount is less then it.
• amountBMin: Minimum amount of the first token to receive.
• toAddress: tokenA and tokenB will be sent to this address.

2. swap.removeLiquidityNAS, is the same as the above expect one NRC20 token is replaced by NAS.

• token: The contract address of the token.
• liquidity: The amount of LP token to burn.
• amountTokenMin: Minimum amount of the token to receive.
• amountNASMin: Minimum amount of NAS to receive.
• toAddress: token and NAS will be sent to this address.

Swap functions

1. swap.swapExactTokensForTokens, when the amount of the source token is determined.

• amountIn: The amount of the source token, or "token0".
• amountOutMin: The minimum amount of the destination token, or "tokenN". The tx will fail is actually amount is less then it.
• path: JSON string of ["token0", "Token1", ... "TokenN"]
• toAddress: TokenN will be sent to this address.

2. swap.swapTokensForExactTokens, when the amount of the destination token is determined.

• amountOut: The amount of the destination token, or "tokenN".
• amountInMax: The maximum amount of the source token, or "token0". The tx will fail is actually amount is more then it.
• path: JSON string of ["token0", "Token1", ... "TokenN"]
• toAddress: TokenN will be sent to this address.

3. swap.swapExactNASForTokens, similar to swapExactTokensForTokens, but token0 must be WNAS, and tx sender needs to send NAS.

• amountOutMin
• path
• toAddress

4. swap.swapTokensForExactNAS, similar to swapTokensForExactTokens, but tokenN must be NAS

• amountOut
• amountInMax
• path
• toAddress

5. swap.swapExactTokensForNAS

• amountIn
• amountOutMin
• path
• toAddress

6. swap.swapNASForExactTokens

• amountOut
• path
• toAddress

Other functions

1. swap.getAmountsOut, estimate swap result given the provided amount, called before swapExactTokensForTokens,

• amountIn
• path

2. swap.getAmountsIn, estimate need amount given the wanted amount, called before swapTokensForExactTokens

• amountOut
• path

3. swap.getPair, given token0 and token1, get the details of the pair.

• token0
• token1

4. swap.allPairs, no parameter, get all pairs of the swap