This maybe just a simple Javascript issue, but it's in the context of running under Truffle. I can't seem to access my object variables coming back from my function; thus the tests are failing with error about the toString being undefined. So I added console.log code to show the values...

To avoid rewriting repetitive, code, I created this function:

async function GetAndShowUserBalances(description, userName, userAddr) 
  let balanceTokens, balanceEth 
  balanceTokens= await exchange.balanceOf(token.address, userAddr); 
  balanceEth  = await exchange.balanceOf(ETHER_ADDRESS, userAddr); 
  console.log("ShowUserBalances: " + description + " " + userName + 
                 " Ether=" + tokensRev(balanceEth) + 
                 " Tokens=" + tokensRev(balanceTokens)); 
   var result = {}; 
   result.Ether = balanceEth; 
   result.Tokens = balanceTokens; 
         console.log('============================================ START result ')
         console.log('============================================ END  result ')

   return result; 


The results look good as JSON in the above console.log.

Then I call it like this:

describe('depositing tokens', async () => {
  let result, user1Balances 
  const numTokensToDeposit = 8 

   describe('success', async () => {

      beforeEach(async() => {
          //approve this smart contract as the exchange address 
          user1Balances = GetAndShowUserBalances("before  depositToken", "user1", user1Addr) 
          await token.approve(exchange.address, tokens(numTokensToDeposit), { from: user1Addr})
          result = await exchange.depositToken(
                         token.address, tokens(numTokensToDeposit), { from: user1Addr})
          console.log("DepositTokens completed: numTokensToDeposit=" + numTokensToDeposit)

      it('tracks the token deposit',async() => {
         user1Balances = GetAndShowUserBalances("after depositToken", "user1", user1Addr) 
         // check exchange token balance 
         //balance1 = await token.balanceOf(exchange.address); 
         console.log('============================================ START user1Balances ')
         console.log('============================================ END  user1Balances ')
         //check tokens on exchange for the user 
         //balance2 = await exchange.tokens(token.address, user1Addr)

Console display:

depositing tokens
ShowUserBalances: before  depositToken user1 Ether=0 Tokens=0
============================================ START result
============================================ END  result
DepositTokens completed: numTokensToDeposit=8
============================================ START user1Balances
============================================ END  user1Balances
  • 1
    Is it possible for depositToken to have failed? The function ´GetAndShowUserBalances´ is declared async but you are not waiting for it to finish.
    – Ismael
    Oct 20, 2019 at 18:27
  • 1
    Function GetAndShowUserBalances is async, and so you probably want to await for its completion whenever you call it. Oct 20, 2019 at 20:13
  • In addition to that (though not directly related to your problem), you are passing two arguments to function balanceOf, which AFAIK takes only one parameter. Oct 20, 2019 at 20:13
  • balanceOf in my contract takes two parms, the first is the erc20Token,, the second is the user's address. I added official answer based on both of your comments, thanks! Oct 20, 2019 at 21:06

1 Answer 1


Comments above gave answer without the syntax. Need the await in the assignment:

 user1Balances = await GetAndShowUserBalances("before  depositToken", "user1", user1Addr) 

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