Hardhat, function and variable are not showing the result

[shakilkhan12]

I have created a simple contract using hardhat, the contract is deploying successfully but when I want to access a variable or function then it's not showing any result, and below is my code

Output

Contract is deploying....
Deployed at 0x5FbDB2315678afecb367f032d93F642f64180aa3

Storage.sol

//SPDX-License-Identifier: MIT
pragma solidity ^0.8.9;

contract Storage {
    uint[] public money;

    function storeMoney(uint256 _money) public returns (uint256) {
        money.push(_money);
        return _money;
    }
}

deploy.js

async function main() {
  const simpleStorage = await ethers.getContractFactory("Storage");
  console.log("Contract is deploying....");
  const simple = await simpleStorage.deploy();
  await simple.deployed();
  console.log(`Deployed at ${simple.address}`);
  await simple.deployTransaction.wait(2);
  const store = await simple.storeMoney(35);
  console.log("You have sent: ", +store);
  const dollors = await simple.money;
  console.log(dollors[0]);
}
main()
  .then(() => process.exit(0))
  .catch((error) => {
    console.error(error);
    process.exit(1);
  });

[krakxn]

Create a getter function instead of using simple.money.

Also, is console.log("You have sent: ", +store); correct?
Try this: console.log("You have sent: " + store);

[othaime-en]

There are several errors in your code:
Remove this line from your code: await simple.deployTransaction.wait(2); It causes an unnecessary wait.
Also, you cannot print out the variable store because it is not a number so just try hardcoding the value in your console.log("You have sent <value>") statement
Also you are trying to access a solidity array directly (which is a tricky affair) in an incorrect manner. checkout https://www.geeksforgeeks.org/solidity-arrays/ for more information on how to work with arrays.
I'd recommend using a different methodology/approach altogether to get the value stored.

[othaime-en]

a couple additions, trying to print the store variable is abit problematic so I would suggest creating a getter function in your solidity contract. along with a public global variable. myNum e.g.

//SPDX-License-Identifier: MIT
pragma solidity ^0.8.9;

contract Storage {
    uint[] public money;
    uint256 public myNum // ADD THIS GLOBAL VARIABLE

    function storeMoney(uint256 _money) public returns (uint256) {
        money.push(_money);
        myNum = _money // ADD THIS HERE
        // return _money; REMOVE THIS
    }
   // ADD THIS GETTER FUNCTION
    function retrieveNum() public view returns (uint256) {
        return myNum;
    }
}

Afterwards, you can modify the deploy script

....
console.log(`Deployed at ${simple.address}`);
await simple.deployTransaction.wait(2);
const store = await simple.storeMoney(35);
const num = await simple.retrieveNum(); //ADD THIS HERE
console.log("You have sent: ", num.toString()); // MODIFY THIS
....

This is just a simple patch to your code. (Not an ultimate solution) but will give you short term results of what you want.
You still need to find a better way to get all the contents of your array though.

[shakilkhan12]

Thank you now it's working but in remix, we can access very easily public variables but why not in hardhat

[othaime-en]

Yes. In remix it is possible due to its user-friendly interface. Remix does everything for you, has a way to retrieve the values and renders them for you. But in hardhat, we are building the interface ourselves so it is abit hard to retrieve the values especially at a beginner level. That's why I told you need a better way of retrieving the values stored in an array.

[shakilkhan12]

Thank you, brother!

[othaime-en]

Glad I could help. Mark as an answer if it helped you. Could help someone else in future. Good Luck.

[alymurtazamemon]

@shakilkhan12 This is how you can achieve what you are trying to do:

You do not need to wait after deploying, so remove it:

await simple.deployTransaction.wait(2);

Here the store will not contain the return value of the storeMoney function, instead, it will contain the transaction response that you cannot concatenate with the string value in the console.log function. And also storeMoney function is storing money and changes the state of the blockchain so for that reason you need to wait for a new block to be mined that contains your transaction.

So instead of this:

const store = await simple.storeMoney(35);
console.log("You have sent: ", +store);

Do this:

const transactionResponse = await simple.storeMoney(35);
console.log("Waiting for 1 block to mine...");
await transactionResponse.wait(1);

After that, you are calling a public money variable that is a type of array, and for each public variable solidity creates a getter function by default, so you are calling it like a variable, instead, call it like a function. Like this:

  const dollors = await simple.money();

Now, as I mentioned above solidity creates a getter function for all of the public variables, but here is a twist, for arrays it creates a getter function with an argument of the index (by default it is set to 0) and returns only the first value of array if you do not specify index while calling the function.

So you do not need to pass the index while printing the response of money function, do this instead:

- console.log(dollors[0]);
+ console.log(dollors);

Hope it helps you.