minter | dApp framework for enabling the creation and collection | Cryptocurrency library

I'm trying to deploy a contract to the ropsten testnet using truffle, but I get the following error:

I have read in various places that NFTs can be created which pay a transaction fee payable to minter of the NFT when it is transferred between owners.

But I don't see in the ERC 721 spec where that property (the amount paid to the creator on transfer of the token) is defined and "written" into the token. I wonder whether fees payable to creators on each sale of a NFT an off chain transaction by the platform on which the NFTs are bought and sold, rather than embodied feature of the NFT enforced by the blockchain transfer mechanism? If it is embodied, where is it specified?

I'm currently using Cucumber to define our test cases in string based feature files. The integration tests will run against a wiremock stub which has date calculations like: "{{now offset='+15 minutes'}}"

I want to validate that the date and time I'm getting from the wiremock stub are displayed correctly, that the date and time are correct and that the table is ordered properly based on that date and time.

We currently have our own implementation to get now +/- X days. That uses some regex and only supports days. I can expand that code and add minutes to that but I would much rather use a library or a standardized piece of code that can parse all date calculations. I haven't been able to find it and would love some suggestions on how to solve this.

To give you an idea of what I'm working with at the moment:

I am working on a very basic erc721 token minting dapp using react and web3. I created an arrow function to mint the tokens but I keep getting an error that the methods is not defined when I try to mint a new token... I am still a beginner so I apologize if there are any rookie mistakes.

my react code

I am confused by the description of PoS algorithm here https://hackernoon.com/a-hitchhikers-guide-to-consensus-algorithms-d81aae3eb0e3

In PoS, the blocks aren’t created by miners doing work, but by minters staking their tokens to “bet” on which blocks are valid. In the case of a fork, minters spend their tokens voting on which fork to support. Assuming most people vote on the correct fork, validators who voted on the wrong fork would “lose their stake” in the correct one.

Is this how Ouroboros algorithm works?

I want to pass a single parameter as array into a function call:

My dataframe contains a URL field which sometimes contains a 13-digit product identifier. I need to extract this product ID and write it to a new column call ISBN. Below are 3 different URL, each with the product ID positioned differently:

i need to pass parameter pass by reference , how can i do

I'm learning Solidity from official documentation and stack on an exercise where I create simple coin: