curly braces?

[h0leee]

i dont seem to understand why, when i'm defining variables, sometimes i need to pus curly braces, like right here: const { deployer } = await getNamedAccounts() const fundMe = await ethers.getContract("FundMe", deployer)

can somebody tell me why please?

[Koowah]

Hi @h0leee ,

await ethers.getContract("FundMe", deployer) returns a javascript object (something like this {"property1":"value1", "property2":value2}).
We're therefore storing that whole object in the constant fundMe with const fundMe.

Similarly, await getNamedAccounts() returns a javascript object that looks like {"user":userAddress, "deployer":deployerAddress, ...}. However, we are not interested in storing the whole object this time. All we want is a single account, the deployer.
So what this syntax const { deployer } does is store the value of the property named deployer in a variable called deployer. This means that now, deployer = deployerAddress. We could also do const {user} = await getNamedAccounts() to get the value of the user property from the getNamedAccount object.

This is called object destructuring.

Hope that explanation wasn't too messy.
Cheers 😄

[h0leee]

Thank you so much one more time! You are an expert at explaining concepts! Wish you the best.

[Nlferu]

Hello @Koowah

Thank you for explanation as it was a bit confusing for me either. If I understand correctly we have to name deployer deployer and other names are forbidden and same for user am I right? I cannot find it predefined in hardhat code, but once renaming deployer to smth else code is getting error, but I was wondering where can we find those names predefined in hardhat source code.

[Koowah]

• @h0leee My pleasure =)

• Hi @Neftyr ,
  No it's the contrary actually. There are no predefined names in the hardhat code : YOU choose the names you want.
  To define them, go to you hardhat.config.js file and look for the namedAccounts field. It should look something like the screenshot above.

[Nlferu]

Hi @Koowah

Yeah that's why I ask because I renamed deployer to deploya in hardhat.config.js and in my script.js and it throws below error:

Once I change deploya into deployer code works without any errors.

[Nlferu]

Hello @Koowah

Sorry for that, I was just using second script in that 1st one and I have changed deployer name only in config and that 1st script but didnt change name in second script, which caused error. Thank you for explanation! Everything works perfectly fine now :)