listening smart contract events through moralis

[sadath-12]

in the video while working with moralis and smart contract in nft marketplace we see events are fired 2 times one is false and other is confirmed .could someone explain the logic behind it ? and how it is only in local server or if it is on even main net too?

[krakxn]

"and how it is only in local server or if it is on even main net too?" Throughout the course, we only use either our Hardhat/Ganache test environment or a testnet. So, unless you are using actual money, no it is not broadcasted in the actual Ethereum network.

[krakxn]

No no, you are confused. Let's simplify here.

1. "see here we have moved 2 blocks that means we are mining or boosting to go ahead by 2 blocks ?" Yes, we are mining two blocks here.

 if ((network.config.chainId = "31337")) {
        await moveBlocks(2, (sleepAmount = 1000))
    }

First, we confirm whether it is a local environment (i.e. developmentChains). If it returns true, we have full freedom of simulating the environment however we like (i.e. evm_mine) and hence, we mine two blocks containing the transactions in the above code snippet (eg buyItem).

2. " if yes then its the authority that miners hold right ? individual can mine their own blocks?" No, miners do not hold any authority. Also no, individuals cannot mine their own blocks (unless it is a test environment, which is clarified above)

In PoW, whoever hashes the block first mines it, essentially a race. And other full-nodes can verify if the block mined is valid or not, so the miners have no authority whatsoever to "mine" invalid transactions (they can alter the order precedence though) or how many blocks they like (only the first to do so gets to).

[sadath-12]

great explanation krakxn !! but can u also give a practical example of these nodes communicate with each as developers ?? because usally what i was doing till now is code the smart contracts deploy and my job was done .. would be better if your statement gives practical examples

[krakxn]

"a practical example of these nodes communicate with each as developers" I cannot comprehend this, do you solely mean the communication b/w the nodes in the P2P network? "as developers" is confusing.

"would be better if your statement gives practical examples" Practical examples of which statement precisely?

[sadath-12]

the second one about miners let say we have a blockchain i bring 1000 friends to connect their transactions and your miner how does practicall u code in your computer ? to mine those transaction ? how do you get to know your transaction was mined first ? how do we know your miner ?

[krakxn]

" how does practicall u code in your computer ? to mine those transaction ?" What?

" how do you get to know your transaction was mined first ?" When you get to know that the transaction you wanted to go through did indeed go through and was successful, i.e. the block containing your transaction has been mined.

"how do we know your miner ?" Depends. If the transaction is on the Ethereum mainnet, pre-merge the miner selected will be of the same race as above; post-merge, the miner selected will be pseudo-random.