Type error in wagmi's usePrepareContractWrite for value

External question — Ethereum Stack Exchange Author: user122142 Original post: https://ethereum.stackexchange.com/questions/151136 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. I have next app with typescript and using wagmi ( https://www.npmjs.com/package/wagmi ) package to work with smart contracts. I am trying to prepare contract write using usePrepareContractWrite and need to send wei to the contract function. I included value ( https://wagmi.sh/react/prepare-hooks/usePrepareContractWrite#value-optional ) but getting a typescript error: Type 'number' is not assignable to type 'undefined'. Here's how I constructed the function: const { config, error } = usePrepareContractWrite({ address: contractAddress, abi, functionName: "purchaseProduce", args: [details?.farmer, details?.index], value: details?.price * details?.quantity, }); How can I fix this type error?

External answer — Ethereum Stack Exchange Author: VsevolodKurochka Original post: https://ethereum.stackexchange.com/a/152233 License: CC BY-SA 4.0 — https://creativecommons.org/licenses/by-sa/4.0/ Adaptation: HTML converted to plain text; contact email addresses removed. I think your problem has to do with you passing an undefined value in "value" field, or in "args", because you are using the "?" operator. Run the code so that you are sure that you have these values. Or using "enabled" mode in https://wagmi.sh/react/prepare-hooks/usePrepareContractWrite