I've managed to run React Native and [email protected] with both rn-nodeify and ReactNativify successfully. I'm aware that web3 v1.0 does build the modules dynamically, but I'm wondering if an...

When I sign a string with the web3.eth.sign() method and web3.eth.accounts.sign() method. The result value of the two signatures is different. I don't know why these two results are different. I'm ...

Trying to follow the wiki example for go ethereum to create a basic contract: https://github.com/ethereum/go-ethereum/wiki/Contracts-and-Transactions Everything seems to work until I get down unti...

I have the following: import { BigNumber } from "@ethersproject/bignumber"; import { parseUnits } from "@ethersproject/units"; const decimals = 18; export const add = (a: stri...

I'm currently following this tutorial (https://medium.com/zeppelin-blog/the-hitchhikers-guide-to-smart-contracts-in-ethereum-848f08001f05) as I try to get into ethereum programming. Step 3 is inter...

I am using org.web3j (4.8.4) and Java 11. I have a smart contract deployed on Kovan network. I want to subscribe to all new events emitted after I call subscribe(...). I am not interested in events...

I would like to calculate the price of a BEP20 token in BNB. I checked poocoin and pancakeswap how they calculate the price. As I see they call continously the bsc-dataseed through web3.js, but I d...

I have two different files which are Project1.sol and Project2.sol Project2.sol is like: import "./Project1.sol"; contract Project2{ address newProject1Address =address(new Project1())...

I have a erc20 token and in another contract I want to create a token swap function. So very easily, one send a usdc token and swap my erc20 token in 1:1 ratio. Problem is how to approve to spend m...

What is the difference between two methods web3.eth.getTransaction and web3.eth.getTransactionReceipt in the web3 library? I tried to read this documentation https://web3js.readthedocs.io/en/v1.2.0...

I have a simple Dapp and I want to sign a transaction but I don't have the private key as a string. The user is using a MetaMask wallet. After they grant web3 access to their account, how can I acc...

I'm currently using ERC721PresetMinterPauserAutoId for a smart contract and the Web3.js library in the Node.js backend server. When I try to call the mint function using this Web3 API: var myContr...

Here is the smart contract, written in vyper, to be tested owner: public(address) name: public(String[100]) total_amount: uint256 @external def __init__(_name: String[100]): self.owner = tx.orig...

I just uploaded a folder of 5 images to IPFS (using the Mac Desktop IPFS Client App, so it was a very simple drag and drop operation.) So being that I’m the one that created and published this fold...

I am using Solc version 0.7.0 installed by npm. When I try to create a Struct that contains mapping, I received an error: "Struct containing a (nested) mapping cannot be constructed." Ple...

i'm learning solidity using Openzeppelin Framework. Currently i'm using the ERC721 Preset Contract (https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC721/presets...

In the statement players.push(msg.sender); I am getting following error: Member "push" not found or not visible after argument-dependent lookup in address payable[] storage ref. Thus I ca...

According to Wikipedia's entry on NFT the minting process "creates a copy of the file recorded on the digital ledger as an NFT". Is that literally true of Ethereum based NFT for example? ...

I have my web3.js detector define as in function below: const ethEnabled = () => { if (window.ethereum) { web3 = new Web3(window.ethereum) return true } else if (window.web3) { web3 = windo...

Why is deploying to Mainnet using Truffle so difficult? Here is a rundown of trying to deploy to Mainnet... Current Gasprice is 110 Wei. Therefore 110000000000 wei Let's plug that in.. mainnet: {...

I'm trying to build a smart contract and inherit some functions to swap ERC20 tokens, Here are my questions? Question A: Is it possible to transfer ERC20 token to smart contract balance?, Please pr...

I am working on an ethereum project but I have some doubts. I have a backend that connects to the blockchain via web3.js. To connect to the blockchain I use a geth node. I understand that the seque...

I trying to generate Ethereum addresses for the HD Wallet keys implemented with bitcoinj library, but I got confused: DeterministicSeed seed = new DeterministicSeed("some seed code here",...

I need to know how to set a proper gas price for my transactions on RSK network. I am familiar with the eth_gasPrice approach from Ethereum: $ curl https://public-node.testnet.rsk.co -X POST -H &qu...

I am new to solidity and I have been trying to print out simple messages using functions in solidity, but I have failed to deploy successfully, and there is an error that I can not figure out what'...