Lesson -7 getNamedAccount is on my nerves

[TimeKeyRoll]

Hi ! I am not able to understand this function even after reading documentation. lol
could anyone help me to understand this in simple and easy language ?

[mattaereal]

Sure!

There's a module called hardhat-deploy which you import, that has this auxiliary function getNamedAccounts() that returns namedAccounts from your hardhat's configuration file if available.

Named accounts are just named variables that reference the accounts / signers that the framework provides. So instead of doing:

accounts = await ethers.getSigners();
deployer = accounts[0];
user = accounts[1];

You can just use the configuration from your screenshot, to do this:
const { deployer, user } = await getNamedAccounts()

You can read more about it here.

From the documentation of the module in question:
getNamedAccounts: () => Promise<{ [name: string]: string }>: a function returning an object whose keys are names and values are addresses. It is parsed from the namedAccounts configuration (see Configuration).

Important note:
The getSigners() approach differs slightly from getNamedAccounts(). If you ever need to connect a smart contract to an account, you should use the first method (because it's a different object).

[TimeKeyRoll]

Thank you very much for the explanation.

[othaime-en]

The function getNamedAccounts() comes with hardhat-deploy. It allows us to access accounts and addresses from the namedAccounts object in hardhat.config.js. This namedAccounts functionality allows us to associate a single name with multiple addresses.

namedAccounts: {
    deployer: { 
        default: 0, 
        1: 0    // On Mainnet we use the first account
        4: 2    // On rinkeby we use the third account
    },
    
    users: { 
        default: 0 
        },
    },
}

In this example, we assign three accounts to the name deployer (just a name to represent the person deploying the contract) and we set the default account to 0 (the first account in the list of 10 accounts that hardhat gives to us).
AFterwards we also assign the account 0 to the chainId 1 (Ethereum Mainnet) So if we connect to our dapp to the mainnet. The 0 account will also be used as the deployer. We could also add 4: 2 to refer to the third account if we were using rinkeby (chainId 4).

For the second name users, we also assign a default address of 0 though we could use any account e.g. 5. With this you could chose to use { users } = getNamedAccounts() in you deploy script.

This example from the documentation is pretty good.

{
    namedAccounts: {
        deployer: {
            default: 0, // here this will by default take the first account as deployer
            1: 0, // similarly on mainnet it will take the first account as deployer. Note though that depending on how hardhat network are configured, the account 0 on one network can be different than on another
            4: '0xA296a3d5F026953e17F472B497eC29a5631FB51B', // but for rinkeby it will be a specific address
            "goerli": '0x84b9514E013710b9dD0811c9Fe46b837a4A0d8E0', //it can also specify a specific netwotk name (specified in hardhat.config.js)
        },
        
        feeCollector:{
            default: 1, // here this will by default take the second account as feeCollector (so in the test this will be a different account than the deployer)
            1: '0xa5610E1f289DbDe94F3428A9df22E8B518f65751', // on the mainnet the feeCollector could be a multi sig
            4: '0xa250ac77360d4e837a13628bC828a2aDf7BabfB3', // on rinkeby it could be another account
        }
    }
}

[othaime-en]

The explanation by @mattaereal above supplements what I forgot to say. Mainly how getNamedAccounts() improves on the getSigners() method provided by hardhat-ethers

[TimeKeyRoll]

Thank you very much both of you.

[TimeKeyRoll]

1:0 as per i understand 1 is the chaindId of Ethereum and 0 is the Index and default account which could be set as per requirement. It could be any chain we set as default. right?

now let's say if its 4:1 and 5:2 . So if we take their first number it represents the chain. for example- 4 for rinkeby and 5 for goerli .. and 1 2 and index.. right? if it's correct then how come we have 4: 2 // On rinkeby we use the third account this line.. 4 is the chainId and where 2 is coming from .. if its not coming from Index..I am sorry for stupid questions but it won't let me move. sorry

[othaime-en]

Hey @MasterofBlockchain good question. Just to be clear, in this format 4:1 or 5:2 , the first number is the chainId and the second is the index of the account address. If you can remember, hardhat gives you 10 local accounts to work with. Or if you are working with Metamask, you could add as many accounts as you'd like right?. So the second number (in our case 1 or 2) is an index used to access an account from this list of accounts that you have.
Also, this indexing follows the general convention in computer science where we start counting from 0. So index 0 is the first account, index 1 is the second account, index 2 is the third account and so on.
So that's why in this line 4: 2 // On rinkeby we use the third account we say on rinkeby (chainId 4) we use the third account (index 2 represents the third account if we start counting from 0)

[TimeKeyRoll]

Thankyou for bearing with me lol

[othaime-en]

Okay. Back when we started, before we started using hardhat-deploy, we used to add the accounts in the accounts section of our networks, just like you have ( accounts: [PRIVATE_KEY] ). Just to be clear, the index we use in the namedAccounts section is determined by the number of accounts in this array
So to configure this scenario, you would change your namedAccounts to:

    namedAccounts: {
        deployer: {
            default: 0, // here this will by default take the first account as deployer
            4: 0, // On rinkeby we use the first account
            5: 1 // On goerli we use the second account.
            "goerli": 1 // Optionally we could use the name instead of chainId. But using chainId is Recommended.
        },
    }

When we don't specify the chainId along with its account index, the default value is used on whatever account we deploy to. So in your case, even if you have 5 networks with several accounts in them, we will always deploy to the first accounts because you the default is set to 0 ( in default: 0 ) However, adding 4:0 and 5:1, we override the default value to the respective indexes.

(Of course the line 4:0 is unnecessary in this case because the index is the same as the default. I just used it for explanation purposes)
So you could just change your deployer object to be:

 namedAccounts: {
        deployer: {
            default: 0, // here this will by default take the first account as deployer
              5: 1 // On goerli we use the second account.
            "goerli": 1 // Optionally we could use the name instead of chainId. But using chainId is Recommended.
        },
    }

So in simple terms, just use the format chainId: index e.g. 4:2 in your deployer to set the index to whatever account you want

[othaime-en]

Sorry that was a lengthy explanation but I hope you get the idea.

[pacelliv]

@othaime-en, using the screenshot from above and considering the following namedAccounts object:

    namedAccounts: {
        deployer: {
            default: 0, // here this will by default take the first account as deployer
            5: 1,
        },
    }

In this case if I run yarn hardhat deploy --network goerli I will deploy my contract on the goerli testnet using PRIVATE KEY or PRIVATE KEY2.

[othaime-en]

@pacelliv It will be PRIVATE KEY2. ChainId 5 (Goerli) is set to account at index 1 which is the second account ergo... PRIVATE_KEY2

[TimeKeyRoll]

Well as we have two accounts in hardhat.config and we have mentioned both of them in deployer ...

so when we run npx hardhat deploy --network rinkeby it will take default account.

and when we run npx hardhat deploy --network goerli it will take account 2 which is mentioned in hardhat.config?

If it's right then how will default will know 0 is for specifically rinkeby not for other accounts?

Im truly sorry for all this trouble.

[othaime-en]

As I have mentioned above, the line default: 0 applies to every network that you have in your hardhat.config except the other networks that are included in the deployer (in this case, 5 for goerli). For example if you had, several networks in your hardhat config e.g. mainnet, ropsten, Kovan, rinkeby, and goerli, all with several accounts.
This code:

namedAccounts: {
        deployer: {
            default: 0, // here this will by default take the first account as deployer
              5: 1 // On goerli we use the second account.
        },
    }

is the same as saying, other than goerli which we have declared we want to use account at index 1, use account at index 0 for every other network there is. e.g.

namedAccounts: {
        deployer: {
            default: 0, // here this will by default take the first account as deployer
            1: 0, // On mainnet use first account 
            3: 0, // On ropsten use first account
            42: 0, // On kovan use first account
            4: 0, // On rinkeby, use first account
            5: 1 // On goerli we use the second account.
        },
    }

However, to save on effort and time, we just use the default index 0.
The default:0 is the designated value for every network you deploy to but then if we want to specify anything an account number for a specific chain, we use the chainId:index format I have explained above. Otherwise just writing default:0 is enough.

[TimeKeyRoll]

Oh man. You are amazing. Finally with your a ton of messages I'm ble to understand haha.

Before I close it I just have a last question..

Whats 'user' which is mentioned in namedAccounts!?

Last doubt and I'm good to go then lol

[othaime-en]

Okay remember at the beginning when I said the namedAccounts functionality allows you to associate custom names to addresses. So we could create several custom names and assign them different account addresses. In this case, we could assign several addresses to the name user or whatever name you'd like through the same approach as we have with deployer.

So let's say you have accounts that you want to use for your user testing, so you would create another name called user

namedAccounts: {
    deployer: {
        default: 0, // here this will by default take the first account as deployer
        5: 1 // On goerli we use the second account.
        "goerli": 1 // Optionally we could use the name instead of chainId. But using chainId is Recommended.
    },

    user:{
        default: 2, // here this will by default take the third account from any network as the user account
    }

    // You could even add another name for maintainer
   maintainer: {
        default: 1, // here this will by default take the second account as the maintainer
    },
}

So with this setup, you could maybe say, have three accounts in every network, and then use the first account as the deployer, the second account at the maintainer, and the third as the user's account. (This is just an example. You do not have to follow this approach)

Therefore in our deploy scripts we could add these new names through: const {deployer, user, maintainer} = await getNamedAccounts()

[TimeKeyRoll]

Almost got it. So what you are trying to tell me is we can fill 'deployer' section for the mainnet and fill 'user' section for testing accounts like rinkbey or goreli.right?

Or in the another way why would we use the custom 'user' name when we have easy way to access other accounts while mentioning?

[othaime-en]

using other names such as user or maintainer isn't necessary at this level so don't let them confuse you. You will understand as you go by. We could just use the deployer with default:0 and we'll be fine. Adding multiple custom names is better when working on huge projects. However in this stage of your journey just stick to using deployer alone.

To answer your question, you don't need to use the custom user because deployer is just okay. I only used the custom names user and maintainer to explain the entire concept. Feel free to come back later in your development journey to understand the custom names concept. But for now, just use deployer alone and discard user
Concerning mainnet and testnets, just use deployer for all of them as we have discussed above.

[TimeKeyRoll]

can't thankyou enough for being Patience with me and explained me in every possible way. Thankyou again very much.

[othaime-en]

Anytime. Glad I could help. Also helped me understand the concept better so it's a win-win lol

Oh and... I'd recommend you mark the first or second answer because they are a summarized explanation of this entire thread. That way they will be a logical flow of the answer from there. (Just a suggestion, this is fine too.)

[othaime-en]

Good luck :)

[mattaereal]

I second @othaime-en's request on selecting a proper answer as the real answer in order not to confuse others :)

[TimeKeyRoll]

I'm truly sorry about that and I have had only one option to chose. So I did it.

Okay Cheers guys.