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Tag: web3js

Decode constructor arguments in solidity

I playing Ethernaut Level 8. The goal is to get access to the private password state variable and unlock the contract. I know one could use await contract.unlock(await web3.eth.getStorageAt(contract.address, 1));, but I want to find the password decoding the input data of the contract creation. Here is the contract. I tried await contract.unlock(“f94b476063b6379a3c8b6c836efb8b3e10ede188”) but that didn’t work. Answer If the

Issue in calling a smart contract function with web3

I’m trying to call the createCustomer function provided in this smart contract https://ropsten.etherscan.io/address/0xD3B462CbF6244ed21CD3cF334Bf8CB44A28795A9#code and we basically have to provide three parameters like string memory _hashedEmail, string memory _name and string memory _phone. So I’ve written the following program to call the createCustomer function However it gives me this err which doesnt make any sense as i’ve already provided the three

Calculate Value from JS Promise

I have assigned a callback function to a variable. The function then returns a promise stating it is fulfilled and the value. I want to be able to return the value and use it to perform a mathematical calculation. Javascript code: In the console I get the below output. Answer Assuming this is the interface you’re using, this is an

Supply ETH to Aave through solidity

I’m trying deposit into Aave V2 Contract Aave’s Code Examples I have code which consumes this like so: When attempting to supply, Metamask displays an error: ALERT: Transaction Error. Exception thrown in contract code. And just a simple button to call it in html: I’m running ganache ganache-cli –fork https://mainnet.infura.io/v3/{{MyProjectId}} The only error I see in the console is: Transaction:

Not including ‘gas’ or ‘gasPrice’ attributes in the ‘options’ object inside of a send() call

Does anyone know what the send() function call to a smart contract method defaults to when you don’t specify gas or gasPrice? Does it automatically allocate sufficient gas and calculate the current average gasPrice? And are those attributes always optional or are there situations where including either one is mandatory? Answer From the documentation, both gas and gas seem to

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