Swaps

Getting a Quote

The process involves using the quoteExactInputSingle function to fetch a quote for swapping a specific token pair. In this example, we’ll focus on the USDC - WIP pair. The function requires input parameters such as the token being swapped, the token being received, the amount to swap, and the swap fee.

The swap fee represents the portion of the trade allocated to liquidity providers. It is one of the key identifiers of a Pool, along with the input and output tokens.

The steps include:

1. Computing the Pool’s deployment address

2. Referencing the Pool contract and fetching metadata

3. Using the Quoter contract to get a quote

At the end of this process, you’ll be able to retrieve a quote for the given token pair and input amount programmatically.

Example Configuration

Here is a basic example configuration:

import { Token } from '@storyhunt/sdk-core';

interface ExampleConfig {
  rpc: {
    local: string;
    mainnet: string;
  };
  tokens: {
    in: Token;
    amountIn: number;
    out: Token;
    poolFee: number;
  };
}

export const CurrentConfig: ExampleConfig = {
  rpc: {
    local: 'http://localhost:8545',
    testnet: 'https://odyssey.storyrpc.io',
  },
  tokens: {
    in: USDC_TOKEN,
    amountIn: 1000,
    out: WIP_TOKEN,
    poolFee: FeeAmount.MEDIUM,
  },
};

The rpc endpoint and tokens can be updated as needed to connect to the desired environment or Pool.

Computing the Pool’s Deployment Address

To interact with the USDC - WIP Pool contract, compute its deployment address using the SDK’s utility function:

import { computePoolAddress } from '@storyhunt/v3-sdk';

const currentPoolAddress = computePoolAddress({
  factoryAddress: POOL_FACTORY_CONTRACT_ADDRESS,
  tokenA: CurrentConfig.tokens.in,
  tokenB: CurrentConfig.tokens.out,
  fee: CurrentConfig.tokens.poolFee,
});

Each Storyhunt V3 Pool is uniquely identified by the input token, output token, and fee. These parameters, along with the PoolFactory contract address, determine the Pool’s deployment address.

Referencing the Pool Contract and Fetching Metadata

Once the Pool address is computed, use it to create a reference to the Pool contract:

import { ethers } from 'ethers';

const provider = new ethers.providers.JsonRpcProvider(CurrentConfig.rpc.testnet);
const poolContract = new ethers.Contract(
  currentPoolAddress,
  IStoryhuntV3PoolABI.abi,
  provider
);

The Pool contract’s ABI can be imported from the Storyhunt SDK core package. Use the contract instance to fetch relevant metadata:

const [token0, token1, fee, liquidity, slot0] = await Promise.all([
  poolContract.token0(),
  poolContract.token1(),
  poolContract.fee(),
  poolContract.liquidity(),
  poolContract.slot0(),
]);

These values are essential inputs for quoting functions.

Referencing the Quoter Contract and Getting a Quote

Use the Quoter contract to fetch trade quotes without executing the trade:

const quoterContract = new ethers.Contract(
  QUOTER_CONTRACT_ADDRESS,
  Quoter.abi,
  provider
);

const quotedAmountOut = await quoterContract.callStatic.quoteExactInputSingle(
  CurrentConfig.tokens.in.address,
  CurrentConfig.tokens.out.address,
  CurrentConfig.tokens.poolFee,
  fromReadableAmount(
    CurrentConfig.tokens.amountIn,
    CurrentConfig.tokens.in.decimals
  ).toString(),
  0
);

The fromReadableAmount() function converts token amounts to their smallest units based on the token’s decimals. The result is the estimated number of output tokens for the swap.

Quoting Methods

The Quoter contract offers four methods:

1. quoteExactInputSingle: Estimates output for a given input amount in a single pool.

2. quoteExactInput: Estimates output for a given input amount across multiple pools.

3. quoteExactOutputSingle: Estimates input required for a given output amount in a single pool.

4. quoteExactOutput: Estimates input required for a given output amount across multiple pools.

For multi-pool trades, use quoteExactInput or quoteExactOutput. Keep in mind that Pool liquidity limits the maximum token output available for a swap.