TypeError: Cannot use 'in' operator to search for 'NaN' in undefined

[Kiranpreetsingh]

const chainId = parseInt(chainIdHex)
> 14 |     const raffleAddress = chainId in contractAddresses ? contractAddresses[chainId][0] : NULL

Can anyone Tell me why I'm getting this error...

[Magofoco]

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Errors/in_operator_no_object

Try something like:
const raffleAddress = contractAddresses.indexOf(chainId) !== -1 ? contractAddresses[chainId][0] : NULL

[PatrickAlphaC]

Can you show how contractAddresses is imported?

It's saying that contractAddresses is null

[jackwillis517]

Hi Patrick,

I'm running into the identical error, here is a section my LotteryEntrance.jsx and the contractAddresses object from its corresponding json file:

import { useWeb3Contract } from "react-moralis"
import { abi, contractAddresses } from "../constants"
import { useMoralis } from "react-moralis"
import { useEffect } from "react"

export default function LotteryEntrance() {    
    //Moralis knows about chainId because of the provider that wraps the app in _app.js
    //Its in hexadecimal though so convert it, in the const we grab chainId a rename it to chainIdHex
    const { chainId: chainIdHex, isWeb3Enabled } = useMoralis()
    const chainId = parseInt(chainIdHex)
    const raffleAddress = chainId in contractAddresses ? contractAddresses[chainId][0] : null`

Here is the contractAddresses object and the index.js file doing the exports from the constants directory:

{"31337":["0xCf7Ed3AccA5a467e9e704C703E8D87F634fB0Fc9"]}

const contractAddress = require("./contractAddresses.json")
const abi = require("./abi.json")

module.exports = {
    abi,
    contractAddress,
}

Thank you so much for the help and the huge tutorial it's taught me a lot.

[PatrickAlphaC]

Can you do a console.log(contractAddresses) in there somewhere to see what they are being imported as?

[jackwillis517]

I found the bug, in my index.js file I was exporting contractAddresses as contractAddress.

[Lavishq]

Thanks for this, I had the same issue and found your answer :)