getPriceImpact

function getPriceImpact(
    uint256 _tokenAmount,
    address[] memory _path
) public view returns (uint256 priceImpact)

//수수료 사용 유무에 따라 swapFee 지정(30 = 0.03%)
uint amountInWithFee = amountIn*(10000-swapFee)
uint numerator = amountInWithFee*(reserveOut);
uint denominator = (reserveIn*10000)+amountInWithFee;
destAmount = numerator / denominator;


amountA = (amountIn*(10000-swapFee))/(10000)      
amountInFee = (amountA*reserveB) / reserveA
if (amountInFee <= destAmount) {
    priceImpact = 0;
} else {
    priceImpact = (((amountInFee - destAmount) * 10000) / amountInFee);
}

// 영향도 얻기
await routerContract.getPriceImpact(
    10000,
    [mockToken0Contract.address, mockToken1Contract.address]
)

// 결과 (0.02%의 영향도)
BigNumber { value: "2" }