nft | Crypto Collectible NFT Tutorial with ERC-721 Tokens | Cryptocurrency library

Try:

The CSS_SELECTOR that you are using

When any contract writes an ERC721 compliant transaction to Ethereum, marketplaces like OpenSea and Rarible are able to monitor new blocks (e.g. via event streaming) for new token creation. Since this information is public, information such as the issuing contract id, owner address and token id are immediately available and can be retrieved. Additional information about the contract can also be obtained from the contract constructor.

Additionally, one of the methods on an ERC721 contract is tokenURI. By navigating to this URI (often stored on immutable storage like IPFS), anyone observing the blockchain can retrieve additional metadata information about the token. This metadata usually includes an image, description and other custom attributes which describe the NFT. This allows marketplaces to render the NFT on their exchanges.

Actually I too got this error in morning. Somehow I believe default gasPrice is not picked up. So I just updated my hardhat config file with following :-

First off all, you need to show us the underlying implementations. However, I can speculate that these are unmodified openzeppelin implementations for ERC721Enumerable and Counters.

For your case only, using Counter seems a little bit pointless to me.

1. It increases your deployment costs(just a little bit) because of redundant code coming from Counter library
2. You already know the length of your tokens array, why keep it twice? Counters is created for situations where you don't know the number of elements, like a mapping.

I am not guaranteeing correctness of the following analysis

Calling totalSupply (looking from opcode point of view) will:

• jump to totalsupply (8 gas)
• sload tokens.slot (200) gas

However, while using Counter, you sstore (>= 5000 gas) each time you decrement and sload (200 gas) each time you read.

As long as i am not mistaken about Counter using storage, and therefore sstore and sload opcodes, second variant will use much less gas.

You can use flatMap to do this:

I figured it out. There's two fixes from this article: https://medium.com/@rasmuscnielsen/how-to-compile-web3-js-in-laravel-mix-6eccb4577666

Easy way, Need to change import:

To obtain all NFTs under a user account, the following conditions are required:

1. A collection needs to be created under the account to store NFT.
2. The collection provides a public method to query its NFT list.

Last time I checked there was no way to pass a struct to a constructor function (see here this 2018 answer). It says that:

...you cannot pass struct to a constructor as it will be receiving its input outside from the blockchain. Only the private and internal functions can expect structs as input parameters.

The solution is to use "primitive" data types as inputs. For your particular case the constructor function could be modified to accept one NFT object like: