How can I make a call and get the return values

[Madeindreams]

I'm trying to send a call and get the expected return.

The function

    function quoteExactOutputSingle(
        address tokenIn,
        address tokenOut,
        uint24 fee,
        uint256 amountOut,
        uint160 sqrtPriceLimitX96
    ) external returns (uint256 amountIn);

The code :

    const ABI = ["function quoteExactOutputSingle(address,address,uint256,uint256,uint256)"]
    let iface = new ethers.utils.Interface(ABI);
    const data = iface.encodeFunctionData("quoteExactOutputSingle",[ WETH,DAI,500,'100000000000000000000',0]);
  
    await PROVIDER.call({
        to: UNISWAP_V3_QUOTER,
        data:data
      });
 

I get an error without revert message

error: Error: VM execution error.
Reverted 0x

What am i doing wrong?

[Madeindreams]

This is working. I get a receipt and payed the gas for it. But i should be able to get the returned value without paying the gas.
How can I achieve this?

    const ABI = ["function quoteExactOutputSingle(address,address,uint24,uint256,uint160)"]
    const contract = new ethers.Contract(UNISWAP_V3_QUOTER, ABI, signer);
    let iface = new ethers.utils.Interface(ABI);
    const data = iface.encodeFunctionData("quoteExactOutputSingle",[ WETH,DAI,500,'100000000000000000000',0]);
  
    let TX = await contract.quoteExactOutputSingle(WETH,DAI,500,'100000000000000000000',0)
    const receipt = await TX.wait(1)
    console.log(receipt)

[ricmoo]

You can use contract.callStatic.quoteExactOutputSingle(…) to use a call instead of send.

[wagekuk]

is there any way to get emitted events from a callStatic return value?

[zemse]

callStatic just does an eth_call, which does not provide any events emitted info.

If you can't just do the transaction, I don't think there are super handy ways to do that.

• You can do the transaction on a mainnet fork on hardhat or ganache, which is like doing the transaction but on a fake chain and then accessing the logs.
• You can extract logs from debug_traceCall or trace_call which is a bit advanced. This is mostly how front runners do stuff.

[Madeindreams]

is there any way to get emitted events from a callStatic return value?

If the call you made emit an event you will be able to get it if you listen for it but you will get it on the block where it was emitted.

[wagekuk]

but a callStatic won't actually make an event be emitted & it won't be included in a block, so I guess the answer is no.

[Madeindreams]

Sorry yes I should have mention that the event only get emitted if you make the call and pay gas.