Category "smartcontracts"

Import web3 not found... in solana web3.js

I npm installed everything, yet only web3 is not working? Is this a bug or is there an alternative to this solution? import React,{useEffect, useState}from 're

use TransferFrom in solidity smartcontract ( ERC-20 )

I Need to Write a Smart Contract, In This Smart Contract User Can Send Token to Each Account in ERC-20 Network. sender :0x5C2879Ec550e2F65D557b540B7DEAB3A6d478d

How should I handle smart contract structure change in NEAR protocol?

Suppose I have a contract ... pub struct Contract { collection_a: Vector<String>, } After I deploy this version, when I change the data structure of my

Is there a way to fetch transactions history on a specific contract using chainlink?

Here is my use case I have a smart contract that emit an event . I am new to chainlink , so my question if someone know how I can track that event history with

Can I subscribe event fire from smart contract's events with NodeJS?

I just wrote smart contract function with fire event like this. And create my node.js application with following code. const express = require('express') cons

Member "team1Score" not found or not visible after argument-dependent lookup in type (contract Game) - Solidity

I'm on a course and have run into a problem. I am trying to make a function that shows the difference in team score from the perspective of the team in the vari

brownie AttributeError: 'NoneType' object has no attribute 'getEntranceFee'

Macbook Pro : Monterey Intel Core i7 Brownie v1.17.2 I am learning solidity according to reference(https://www.youtube.com/watch?v=M576WGiDBdQ&t=25510s). Wh

How to solve insufficient allawance issue when calling transferFrom? web3.js

I'm struggling with the trasferFrom method of my standad ERC20 contract. I'm working with web3.js and INFURA I have wallet1 with 50 token allowance, now if I ca

there is a problem in the gas requirement

I have been written a smart contract, I am trying to execute the following code but I have these problems: 1- "Gas requirement of function EKM.register_PK is in

Near Protocol, Smart Contract

When I run the command yarn build:release i get the error "command not found: asb" enter image description here

window.solana not found on js web3

I want to connect a Solana wallet (phantom or any other) to a web aplication through the js web3 library. I've read docs for most wallets and it seems like it's

.balanceOf is not a function - Interact with existing Contract on Blockchain

I want to automate my staking on The Sandbox. For that I need in the first step to interact with the mSand-Matic Pool Contract. It is this one: https://polygons

AttributeError: 'NoneType' object has no attribute '_with_attr' - Python running tests with pytest

My environment is : Python 3.9.9 Pytest 6.2.5 Brownie 1.17.1 I'm working on the test_fund_me.py from Patrick Collins' Smart Contract tutorial on Youtube; at thi

What is the 16 in (chainId, 16) in an Eth smart contract that is on the Rinkeby network

I am new to smart contracts and I am working on an Eth Rinkeby dapp and was wondering if anyone can tell me what the "16" means in this section: } network =

How to deploy multiple smart contracts using hardhat-deploy

I have two smart contracts that I want to deploy. I want to deploy the first one, then pass the address of the first into the constructor of the second one. I a

Restrict function access ONLY to one other specific contract in Solidity

I have a security problem in my Solidity contracts and I can't figure out how to fix it. The flow goes like this: First, we create an instance of contract A; Cr

error[E0412]: cannot find type `ProgramResult` in this scope

use anchor_lang::prelude::*; declare_id!("Fg6PaFpoGXkYsidMpWTK6W2BeZ7FEfcYkg476zPFsLnS"); #[program] pub mod myepicproject { use super::*; pub fn start_st

Matic Remix Warning! Error encountered during contract execution [execution reverted]

I forked a contract, it is a Baked Beans fork on MATIC, I deployed the contract through Remix, now when I try to deposit through my website script, Metamask say

How to send ETH to a contract function with ethers.js?

I am trying to send ETH to a contract function from a web app via metamask and ethers.js. So far I have tried: const provider = new ethers.providers.Web3Provide

how can i call a function in a smart contract from an abi json file smart contract

i have the abi json file for a contract and i want to use its functions in my smart contract. is there any way to do it? for example i have a contractA.sol and