I have a function on my contract that return true if the address on one list is equal to the msg.sender. The function works fine on remix but when I call it utilizing javascript with next.js and web3.js it is returning false. What could it be?

  • 2
    Quite obviously the msg.sender is some other address. Apr 15 at 7:25
  • Sure, but why? The address at zero is the address that should be calling the function and its the same that is added to the list of addresses...
    – Hash1
    Apr 15 at 8:02
  • Please clarify your specific problem or provide additional details to highlight exactly what you need. As it's currently written, it's hard to tell exactly what you're asking.
    – Community Bot
    Apr 15 at 8:51
  • The problem was that when i set the web3 provider by default it calls the function of the contract with the first account connected to the dapp, so i need to specify the account that i want to use when passing the .call() method on the web3js! Tks for your help!
    – Hash1
    Apr 16 at 21:40

1 Answer 1


msg.sender does not same in your test code and you logic, you have to send your transaction from msg.sender in your test. For example in web3.js you can use "from:msg.sender" for sending transaction with specify address .sample code is:

let transaction = await yourContract.yourFunction(ag1, arg2,....(other input arguments), { from: msg.sender});

you must use the same msg.sender with an address initiated in the contract.

  • But what if my function in the contract is the type view? In the web3.js the method call() has a from property?
    – Hash1
    Apr 15 at 8:11
  • for view function you can see this question: ethereum.stackexchange.com/questions/60117/… and for call() property goes here: web3js.readthedocs.io/en/v1.8.1/… Apr 15 at 10:49
  • That was it! Tks! i solved the problem simply by adding the .call({from: address[0]}). Reading the documentation and with your help i learned that by default the web3.js call() method set the msg.sender to the first account on the wallet, so especifing the account index in the call method make it work!
    – Hash1
    Apr 15 at 21:45

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