Internal JSON-RPC error when swapping from ethers.js on uniswap - swap

Question

I spend a lot of time trying to understand where is the mistake.
I try to swap USDC to any token on uniswap router v3 with ethers.js on frontend.
I use Polygon network in app and in metamask too.
I have a confirmation in my metamask to approve USDC, but after it I have no confirmation about swapping. I see an error in console:
inpage.js:1 MetaMask - RPC Error: Internal JSON-RPC error. code: -32603 data: code: -32000 message: "execution reverted"
This is my code:
const provider = new ethers.providers.Web3Provider(window.ethereum);
const send_account = await provider.getSigner().getAddress(); //my address
//Swap from USDC to MTS or any other token
addressOfUSDC='0x2791bca1f2de4661ed88a30c99a7a9449aa84174' // Address of USDC in Polygon
const ERC20Contract = new ethers.Contract(addressOfUSDC, ERC20ABI, provider);
swapRouterAddress="0xe592427a0aece92de3edee1f18e0157c05861564"; //Uniswap v3 router
indadr="0x440416D85E5D51424da371297E3d7Ef28312BF62"; //Any token address to which I want to swap
approvalAmount=12; //12 USDC
await ERC20Contract
.connect(provider.getSigner())
.approve(swapRouterAddress, approvalAmount*1000000)
//After this step we see confirmation to spend 12$ in metamask
bn=ethers.BigNumber.from(approvalAmount*1000000); //BigNumber from approvalAmount
const params = {
tokenIn: addressOfUSDC,
tokenOut: indadr,
fee: ethers.BigNumber.from(3000),
recipient: send_account,
deadline: ethers.BigNumber.from(Math.floor(Date.now() / 1000) + (60 * 10)),
amountIn: bn,
amountOutMinimum: ethers.BigNumber.from(0),
sqrtPriceLimitX96: ethers.BigNumber.from(0),
}
const UniswapContract= new ethers.Contract(swapRouterAddress, ERC20ABI2, provider);
dd=await UniswapContract
.connect(provider.getSigner())
.exactInputSingle(params)
console.log(dd);
And after this step I have no confirmation in metamask and error in console: MetaMask - RPC Error: Internal JSON-RPC error. execution reverted
Maybe the problem is that I use two different router ABIs?
Please help me to understand the problem! Thanks in advanse!
I tried to change ABI, router address. Also I tried to use Uniswap V2 router with function swapExactTokensForTokens.

Answer 1

I try to swap USDC to any token on uniswap router v3 with ethers.js on
frontend.
you cannot swap USDC with any kind token. you need to have pool pair contract. for example ETH/USD, you have to find the pool address for WETH/USDC and create a pool contract. WETH is ERC20 version of ETH
you need to get the pool address and create a pool contract to get the immutables.
const poolContract = new ethers.Contract(
poolAddress,
IUniswapV3PoolABI,
provider
);
this is what you set as the first params
tokenIn: immutables.token1,
tokenOut: immutables.token0,
Then you have to have a swap router contract
const swapRouterContract = new ethers.Contract(
swapRouterAddress,
SwapRouterABI,
provider
);
the way how you created the swap router contract is wrong
const UniswapContract= new ethers.Contract(swapRouterAddress, ERC20ABI2, provider);
you are passing ERC20ABI2 here. this should be SwapRouterABI. ERC20ABI2 is used to construct the USDC token contract and other token contract that you are going to swap. Because eventually, you are swapping two ERC20 contracts
If you need to swap ERC20 tokens, first you have to allow the swap amount, so you have to call approve method of token contracts that you construct. you need to allow Uniswap to withdraw money from token contracts.
Finally you call the contract function
dd=await UniswapContract
// maybe you should have const signer= await provider.getSigner()
.connect(provider.getSigner())
.exactInputSingle(params)