Category "solidity"

Implementing fixtures with @nomiclabs/hardhat-waffle

In the official waffle documentation you may find the next way to implement fixtures: import {expect} from 'chai'; import {loadFixture, deployContract} from 'et

Error: TypeError [ERR_INVALID_REPL_INPUT]: Listeners for `uncaughtException` cannot be used in the REPL at Object.compile

I am new to truffle and I work on blockchain project so when I "migrate" in truffle develop, this error occurs. Why ? I change the version of my compiler by 4.2

Paying with ERC20 token

I want to build an NFT that I can paid with an ERC-20 token to mint it. I'm using currently the Mumbai testnet on polygon, and I'm using the Dummy ERC20 token t

Must all nodes on the blockchain execute every smart contract function cal?

I understand why it's important that all nodes on the Ethereum mainnet must execute any smart contract function call which changes the internal state of the con

Error trailing semicolon in smart contract on solidity?

I am trying to write a smart contract and line 1 is bringing up an error : ParserError: Found version pragma, but failed to parse it. Please ensure there is a

The transaction declared chain ID 5777, but the connected node is on 1337

I am trying to deploy my SimpleStorage.sol contract to a ganache local chain by making a transaction using python. It seems to have trouble connecting to the ch

How to initialize a static string array in solidity?

I want to declare an array to store my strings as follows. bytes32[3] verifiedResult; verifiedResult = ["verified successfully", "verified failed", "not clear"]

My dapp doesn't detect when an user change their Metamask Account

I am in the process of building a dapp for a project. I have one last thing to adjust: detect when a user changes metamask account to reset the state but it doe

How to initialize a static string array in solidity?

I want to declare an array to store my strings as follows. bytes32[3] verifiedResult; verifiedResult = ["verified successfully", "verified failed", "not clear"]

TypeError: Cannot read properties of undefined (reading 'getContractFactory') when testing contract

First question so bare with me if it is not very clear, but I'll try my best. I am currently running through a youtube video to test my contract with hardhat, e

sign and verify message with solidity and python

I am trying to perform a certain action say like selling a token only when the message sent to a contract is signed by the contract owner. I knew how I would do

Can smart contracts deploy other smart contracts?

If a smart contract has the compiled bytecode for a contract can the first deploy a subsequent contract? According to Ethereum.org: "To deploy a smart contract,

Error: VM Exception while processing transaction: reverted with reason string 'ERC721: transfer caller is not owner nor approved'

i try to write NFT marketplace and i have problem with reselling items from user that buy item from owner and new, third user. I use next.js + openzeppelin + ha

Member "name" not found or not visible after argument-dependent lookup in struct xxx storage ref[] storage ref

Solifity 0.8.0 with struct struct Placeholder{ string a; uint256 b; } mapping(uint256 => Placeholder[]) public placeholder; why this error Member "b" no

ImportError: No module named solcx

I installed py-solc-x via pip3 install py-solc-x in the terminal but when I run the program, I still get an importerror. What's going on here? My code: from sol

ParserError while compiling solidity code

I am new to solidity. This is my 1st simple project when I do node compile.js & I am getting following error: My Error : { contracts: {}, errors: [ ":

Unhandled Rejection (Error): call revert exception

I am getting this error message when trying to interact with my smart contract on my react front end. I am running localhost3000 and which requires metamask to

Visual Code Studio, File Import Callback not Supported - File Source not Found

While trying to troubleshoot another issue with my project, I must've broken something along the way, but I have no idea how to fix this. These are my import st

How to store each NFT image in a ERC721 contract? [closed]

When creating a ERC721 contract that manages thousands of image NFTs, saving these image byte pixels in arrays on the contract doesn't seem ve

How to store each NFT image in a ERC721 contract? [closed]

When creating a ERC721 contract that manages thousands of image NFTs, saving these image byte pixels in arrays on the contract doesn't seem ve