[SOLVED] How to pass parameters to a contract function dynamically

Moralis General
#1

Hi everyone!

I am having a bad time trying to call to my smart contract inside a loop using useWeb3Contract hook. I am pretty new both to react and smart contract developing so maybe I am doing it all the wrong way.

Well, this is what I have so far:

const {runContractFunction: getByHash} = useWeb3Contract({
        abi: abi,
        contractAddress: address,
        functionName: "getByHash"
    })

And apart from that. I have something like this:

list?.map((item) => {
          getByHash(item.hash).then(.....)  // Call to the function I defined above
}

As far I could understand it is a bad practice (or maybe imposible at all) to use a hook inside a loop, so I am wondering how this could be achieve. I know it must to be a way since it is pretty normal to have mappings in solidity and loop them from the frontend.

In other places I could pass parameters to useContract functions just using state variables as I did here:

const [param1, setParam1] = useState()
const [param2, setParam2] = useState()


const {
        runContractFunction: contractFunctionWithParams,
        isLoading,
        isFetching,
    } = useWeb3Contract({
        abi: abi,
        contractAddress: address,
        functionName: "functionWithParams",
        params: {
            param1,
            param2
        },
    })

But this is not what I need since I want to dynamically call the contract function with the list I loop into.

Any ideas about how can do this?
Thanks in advance! See you!

#2

What do you want to do with the data from getByHash? It would be easier to use the non-hook function if you don’t need the state handling from hooks.

You can also use runContractFunction instead if you only need to call read only functions.

#3

Thanks for the answer! I just need to call a simple read function. I tried with the runContractFunction but because I am working under the hardhat local blockchain, it wont work (unless I am confuse, the hardhat chain is not supported)

I will try the other option you mentioned if it supports hardhat.

#4

useWeb3Contract uses executeFunction (which then uses ethers.js) under the hood. So it should still work with local networks.

#5

Hi! That worked! Thanks a lot!

The solution in case someone has the same problem:

const readOptions = {
                    contractAddress: contract,
                    functionName: "getByHash",
                    abi: abi,
                    params: {
                        hash: match.attributes.hash,
                    },
                };
                const message = await Moralis.executeFunction(readOptions);
````
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