How to set price to NFT token and update that price?

Question

I want to create a market place of nfts. I know how to mint and creat nft but I dont know how to set price of token, how to set list of orders. I read that the price should be set on token contract address. Then how can I set price to token contract address and how to update that price because each user(a person who owns the nft) want to sell as a different price. Should I save the price and list of orders in my database or I should set them on token contract address or maybe in nft?

Answer 1

If you are on a marketplace, you can define an Nft marketplace item the way you want it:

struct NftItem{
    uint tokenId;
    uint price;
    address creator;
    bool isListed;
  }

You can write a _createNft function:

function _createNftItem(uint tokenId,uint price) private{
    require(price > 0, "Price must be at least 1 wei");
    // depends on how you wanna store the nft
    idToNftItem[tokenId]=NftItem(
      tokenId,
      price,
      msg.sender,
      true
    );
    emit NftItemCreated(tokenId,price, msg.sender,true);
  }

when you call the mint function, you can pass price arg, you call _createNftItem function

function mintToken(string memory tokenURI,uint price) public payable returns (uint){
    require("write logic this tokenUri was not used before");
    require("make sure sender is sending the lsiting price");
    _tokenIds.increment();
    _listedItems.increment();
    uint newTokenId=_tokenIds.current();
    // this is a wrapper for _mint
    _safeMint(msg.sender,newTokenId);
     // minting will create an item on blockchain
     // createNftItem is specific to marketplace
    _createNftItem(newTokenId,price);
    
    return newTokenId;
  }