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NFT-Marketplace
Contains contracts for ERC20 Token, ERC-721 token and marketplace contract to list the NFTs and allow users to buy them using the ERC-20 Token. (by abhik-99)
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InfluxDB
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Most likely users would be interacting with an interface infront of this contract so these things can be calculated off-chain without much fuss. But hey, if your client wants to be wasteful, who are you to object? XD The other thing you might notice is the nonReentrant modifier in the function prototype of some functions. This is what prevents a “Reentrancy Attack”. If you are new and unaware of it, just know right now that it’s a pretty big deal and make sure to search up on it later. It’s provided by inheritance from the ReentrancyGaurd smart contract provided by OpenZeppelin. You might also be thinking why are the functions in which we are transacting in ERC20 tokens not declared as payable? That’s because it is not in Ether that we are transacting. Transacting in Eth and ERC20 tokens are two very different things. I believe at the time of writing there an EIP in the pipeline which might change that in the future. For a complete list of EIPs visit https://github.com/ethereum/EIPs and you will find all of them inside the EIPS directory.
Delisting NFTs from marketplace – It’s as easily done as deleting the key/item ID of the NFT from the marketplace. Since we are using a mapping that is one option available to us. Other thing you might not want to do but is possible is using another Boolean flag for indicating if the item is delisted or not. You can also take it many steps further and make a marketplace which can accommodate multiple NFT contracts and tokens. Wrapping things up The code for this tutorial is available on my GitHub here In this article we saw how easily an ERC 20 token can be created for transacting of ERC 721 type NFT on a custom marketplace contract. Hopefully, not everything went over your head. There are a few topics I would love to explore in the future articles like testing in hardhat (using these contract), taking this marketplace a step further and use Uniswap to add feature for buying through multiple tokens among other things. I hope you liked reading through it all and if you have a suggestion, feel free to get in contact with me over Twitter or over my mail ([email protected]).