Passing constructor params in a Contract

[ghost]

Hi

I was wondering how to pass contructor values into a constructor.

For example, my contract constructor looks like:

   constructor(address _token) ERC20("Blueberry-LP", "Blueberry-LP") {
    require(_token != address(0), "invalid token address");
    tokenAddress = _token;
    }

In ethers I would do like this:

    const exchange = new ethers.Contract(
      tokenAddress,
      Exchange.abi,
      this.state.signer
    );

I saw there is also the method attach() but when to use attach?

[zemse]

You need to pass constructor arguments only while deploying a contract. You can refer to ContractFactory docs.

const factory = new ContractFactory(Exchange.abi, Exchange.bytecode, signer)

// Deploy an instance of the contract passing in constructor arguments
contract = await factory.deploy(_token);

contract.address // address of the deployed contract

Once you deploy a contract, you get the contract object like above.

But if you already have deployed a contract and have an address of the deployed contract (contract.address), that's when you have two ways:

• use the new ethers.Contract code that you mentioned to get the contract object.
• Use factory.attach.

Does that help?