Can someone please show how to use getAmountOut/getAmountIn functions of UniswapV2 Router2 smart contract using ethersjs?

Question

I tried:

• getting pair of DAI-MKR pair from factory contract (using address, ABI, Infura RPC provider)

• Used this pair contract to get reserves. converted these reserves from hex to decimal using parseInt(reserve0, 16)) and parseInt(reserve1, 16))

• used these in the router contract:

  const uniswapV2Router2 = (uniswapV2Router2_add, uniswapV2Router2_ABI, provider) const maxAmount = await uniswapV2Router2.getAmountIn(1, reserve0, reserve1)

But I got following error:

const maxAmount = await uniswapV2Router2.getAmountIn(1, reserve0, reserve1); // amount of MKR for 1 DAI
                                             ^

TypeError: uniswapV2Router2.getAmountIn is not a function

Answer 1

This error I guess is caused by your router abi or router address error because I do not have information on the previous code so I can only speculate it

But there are several obvious errors in your code

You should chang this

const maxAmount = await uniswapV2Router2.getAmountIn(1, reserve0, reserve1); // amount of MKR for 1 DAI

to

const maxAmount = await uniswapV2Router2.getAmountIn(1, [reserve0, reserve1]); // amount of MKR for 1 DAI.

Because [reserve0, reserve1] is an array :)