Block waiting confusion..

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await FundMe.withdrawal()

Or

const tx = await FundMe.withdrawal() await tx.wait(2)

the difference in upper two statements are wait(2). How does it help in the function ? And What is the purpose of 2 block confirmations.
Appreciate easy language for learning and understanding.

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@othaime-en

[othaime-en]

@MasterofBlockchain please mark the correct answer. This doesn't seem to answer your question.

[TimeKeyRoll]

@othaime-en okay. Don't get mad on me bro. Lol

I have changed it. :D

[othaime-en]

Lol I'm not mad. 😄

[othaime-en]

Hey @MasterofBlockchain as we know, the code await FundMe.withdrawal() executes the withdraw function but it also returns a transaction receipt (in the form of a promise). So doing const tx = await FundMe.withdrawal() actually captures the txReceipt if you want to use it. Part of the methods that comes with the transaction receipt is the wait() function/method. The syntax for .wait() is transaction.wait(Number of confirmations)
What the .wait() method does is that we are telling hardhat to wait for whatever confirmations we put inside the bracket to resolve the transaction receipt. So if we put .wait(2) we are saying that we want to wait until our transaction has been confirmed in 2 mined blocks before we proceed.
This feature is useful in cases where we want to read data from the blockchain. I know you've encountered a scenario where transactions take a while before they appear on etherscan right? This is because sometimes, they are waiting to be confirmed by several miners before being permanently recorded. So we want to avoid a situation where we are requesting data from the blockchain when it hasn't been confirmed yet since that would mean we wouldn't be able to read anything yet. So we are waiting for these confirmations to make sure that when we indeed read something or interact with the blockchain, the data we want has already been confirmed and is in the blockchain. The higher the confirmation number, the higher the chances that our data will have been recorded on the blockchain when we request it However, 2 is enough, Using a higher value will just increase the latency of our program.

[TimeKeyRoll]

very great and yet simple way to explain..
still left with a question..
I understand now what is wait(2) and its number inside.
so whenever we use wait() keyword it means to wait for certain blocks to be mined and keep on going once those certain blocks are mined..right? so it can give us assurance the data has been stored on blockchain. Am i correct?

And lets say if i use wait(2) for withdraw function. how it is working in backround? so when i call withdraw function it makes 2 blocks and proceed ..if yeah? Are those 2 wait blocks are empty? or have something inside?

Sorry but thankyou!

[othaime-en]

T0 be clear, the wait() function doesn't mine the blocks it just resolve the promise once the blocks are mined. Remember that on a blockchain, there are two types of nodes, miners and us users. So our job is is just to interact with the blockchain and not mine anything. The wait() just waits for the miner nodes to mine blocks and resolves once these blocks are mined. so we aren't creating any empty blocks.

[TimeKeyRoll]

So wait() function resolve the promise when the desired blocks are mined by miners.. Got it!
AND what's the background of wait(2) function looks like on miner side?

So for example when we use wait() function so miners will to have mine two blocks for our promise to get resolved.. Got it. But what is those blocks holding on miners side!?

[othaime-en]

Miners only mine transaction data. The wait() method is a way we interact with the blockchain so miners have nothing to do with it. Miners don't know that we want to wait 2 blocks, they just mine the transactions. In this case, the miners have the our withdrawal transaction, nothing else.
Now ethers (what we use to interact with the blockchain) is what interprets the .wait() method and waits 2 block confirmations that our withdrawal() transaction before resolving the promise.

[krakxn]

1. await FundMe.withdrawal() just waits for the statement to execute (as await is a JS thing). There is no blockchain technique involved here.

2. const tx = await FundMe.withdrawal() await tx.wait(2) here, wait(2) mines two blocks (remember, blocks consist of transactions, mining is basically confirming those blocks of transactions to the blockchain) to confirm the withdrawal transaction of the FundMe contract. (context: wait() is used to mine blocks)

Why do we need to mine those transactions? Well, that is precisely how transactions work in a blockchain, they need to be mined for them to go through. So, we are confirming the withdrawal transaction

Hence, the high gas fees when the network is congested with many transactions as they need to be mined. (which leads to a low supply of miners mining the same amount of transactions, hence the high cost of gas fees)

[TimeKeyRoll]

@krakxn thankyou so much man.