Web3-core-helpers error: Uncaught (in promise) Error: Provided address "undefined" is invalid,

Question

When I launch the app with with react.. this error occur when my exchange contract is loaded.. Here is the code i wrote to talk to the blockchain:

export const loadBalances = async (dispatch, web3, exchange, token, account) => {
  const etherBalance = await web3.eth.getBalance(account)
  dispatch(etherBalanceLoaded(etherBalance))

  const tokenBalance = await token.methods.balanceOf(account).call()
  dispatch(tokenBalanceLoaded(tokenBalance))

  const exchangeEtherBalance = await exchange.methods.balanceOf(ETHER_ADDRESS, account).call()
  dispatch(exchangeEtherBalanceLoaded(exchangeEtherBalance))

  const exchangeTokenBalance = await exchange.methods.balanceOf(token.options.address, account).call()
  dispatch(exchangeTokenBalanceLoaded(exchangeTokenBalance))

  dispatch(balancesLoaded())
}

web3 v1.0.0 beta46 Truffle v5.0.5 (core: 5.0.5) Solidity v0.5.0 (solc-js) Node v9.10.0

Here is the error when i use the debugger

Update: The error i get when i update to web3 v1.2.1

Answer 1

You declared you function as async but never used the async/await pattern. I added the await at the correct position for you.

Try this:

export const loadExchange = async (web3, networkId, dispatch) => {
  try {
    const exchange = await web3.eth.Contract(Exchange.abi, Exchange.networks[networkId].address)
    dispatch(await exchangeLoaded(exchange))
    return exchange
  } catch (error) {
    console.log('Contract not deployed to the current network. Please select another network with Metamask.')
    return null
  }
}