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Questions tagged [javascript]

JavaScript is a dynamic, weakly-typed language used for client-side as well as server-side scripting.

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0answers
91 views

Solidity function calls from javascript work locally but fail on ropsten,kovan etc with Error: Returned values aren't valid, did it run Out of Gas?

I have a smart contract whose function calls works fine when called locally using javascript and ganache. But when I deploy to ropsten and others, the calls to its functions fail with Error: Returned ...
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1answer
277 views

How can you make HTML Text Box print the value of console.log?

How can I enter input data value in HTML Text Box? The output is good in console.log, but the HTML Text Box displays the error Object Promise. I want to know how to print the value of web3.eth....
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0answers
78 views

Ether transaction does not reflect in ganache

Hi am developing a etherium DAPP. In that for every user registration some ether will get transfer from user to contract... Everything work perfect but the transacted ether is not reflecting in ...
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1answer
77 views

address(this) in solidity is returning wrong contract address

This is my cantract code which I was using in truffle pragma solidity 0.5.16; contract Test { function getAdd() public view returns(address){ address add = address(this); return ...
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2answers
38 views

Are events collected in Web3js asynchronously?

I am collecting a set of previously generated events, based on certain filters/test, and trying to display them on my HTML page. The code I am using to fetch the events is as follows: var eventList = ...
1
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1answer
475 views

Could not find a declaration file for module 'solc''

I have installed solc without any errors or warning, but when i am trying to run node compile.js command in cmd then i am getting following error On checking the code, i found that "const solc = ...
1
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1answer
361 views

DApp examples containing complete source code

can someone provide me some high quality ethereum dapp codebase examples? This should comprise of not only the smart contract codebase but also the app codebase , complete with the front end UI (...
1
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0answers
93 views

Contract not returning error to React Interface

I have a contract which I've tested with Mocha and Remix and is working just fine. The problem is when I'm running it with my React Interface. When I call a function in my solidity contract that ...
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0answers
80 views

Kovan transaction never being mined

I have setup an Infura account to send transactions on the kovan network. This is the code I want to use to send ether to another account (current one has 1 ether from a faucet): var Web3 = require('...
2
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1answer
321 views

Drizzle cacheSend outputs “cacheSend is not a function” error, but the tx works when using send

I'm using Drizzle and react-hooks in my new open source project, but cacheSend outputs always "cacheSend is not a function" This line of code with send works as expected const stackId = contract....
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1answer
35 views

Smart contract function not returning expected output

I'm quite new at this and I'm learning both Solidity, Javascript and React to play around with smart contracts. My contract ran well in Remix and in a local test net. I ran a bunch of tests using ...
1
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1answer
218 views

Signing a raw transaction, wrong R and S values

I am trying to sign a raw transaction in javascript without relying on dependencies like web3, ethereumjs, etc. I am following the python tutorial found here, and porting to JS as I go: https://...
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1answer
19 views

input from second form won't display [closed]

The project is to change someone's name, and I have two forms for two names. When I run the code in solidity, I can change the names, no problem. When I run it with ganache, the name change in the ...
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1answer
123 views

ERC20 Transaction failing due to invalid nonce value

I am trying to send an erc20 transaction but I keep getting an error telling me that the account I'm sending the transaction from has a nonce value of 1 while the tx has a nonce value of 31613. I am ...
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0answers
678 views

Web3.js Batch Request Limit?

I'm trying out Batch Request provided by web3.js. In the example below I want to test making 300 transactions but i get the error log displayed below. I'm trying to figure out the error log but it ...
0
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1answer
18 views

What does instance refer to in solidity/JavaScript

DToken.deployed().then(function(instance){ token = instance; }) This code I saw in truffle test. Can someone please tell what does this "instance" parameter refer to?
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1answer
69 views

web3.eth.defaultChain returns undefined

Hi I am trying to make a call to the Dai contract in the Kovan testnet using web3.js and have to set the value of web3.eth.defaultChain to 'kovan'. The docs state that the default value for web3.eth....
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1answer
29 views

How to send the RFID card no read using Raspberry Pi to smart contract so the details can be stored on Ethereum blockchain? [closed]

Raspberry Pi reads an RFID card and has to send the RFID number to the smart contract to check further details related to the RFID number. Based on the details the payment is done and stored on the ...
0
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2answers
174 views

Error sending transaction to smart contract [closed]

I have problem with this, I'm doing a tutorial about how to interact with blockchain through web3, I get some response from blockchain, but the problem is when I try to send transaction or try to ...
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1answer
46 views

Unhandled promise rejection

The code below gives me the exceeds allowance or always failing transaction error but when i check my contract on remix i can see that the transaction goes through, makes the correct state changes ...
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0answers
84 views

Just not able to install Web3 through powershell

After reading a lot of articles about how to install Web3j in windows. I also tried following this article : https://kauri.io/generate-a-java-wrapper-from-your-smart-contract/...
0
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2answers
132 views

gas exceeds allowance

I'm testing my smart contract on ropsten and I have written an async function that lets me send TRANSACTION transactions from TRANSACTION different accounts. For some reason when TRANSACTION > 20 i ...
0
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1answer
470 views

How to import web3 utils in front end Javascript

I need to use a web3.utils.soliditySha3 function in my javascript but web3.utils gives: Cannot read property 'soliditySha3' of undefined My script can't use .require as well. I tried: <script ...
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1answer
479 views

How to Keccak 256 hash in front end JavaScript before passing it to my smart contract

I would like to build a simple JavaScript (JS) front end that checks if a field submitted is the pre-image of a keccak256 hash I already know in my smart contract. I currently use the following: ...
0
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1answer
17 views

How to large amounts of old block

I have to scan a large amounts of old block. I using subcribe newBlockHeaders so I have new_block.number (2s/block). Then I find in db the latest block number (db_block.number). I use for(i=db_block....
1
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1answer
41 views

Exit process after sending multiple tx asynchronously

I have written a function that allows me to send an arbitrary amount of transactions, asynchronously, to my smart contract. However the process stays open even after the last transaction has finished. ...
4
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2answers
2k views

Sending multiple transactions in the same block with incremented nonces

I need to send 0.1 ETH to 10 unique addresses from the same address at the same time. I am manually incrementing each transaction's nonce, and the transactions are sent successfully. However, each ...
1
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1answer
36 views

How to fix Data location must be “memory” for return parameter in function, but none was given.?

pragma solidity >= 0.5.0 < 0.7.0; contract Adoption { address[16] public adopters; function getAdopters() public view returns(address[16]) { return adopters; } function adopt(uint ...
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0answers
75 views

Proper way to fire smart contract function passing an array with web3js

I'm using web3js version 0.20.7 The smart contract originally had a function (called whiteListAddress(address _address, bool value) ) that took an address and a boolean value, which was called like ...
0
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1answer
119 views

Get contract's balance in js test

When getting contract's balance on Remix, it returns the correct answer. But when the same function is called with JS Test, it returns a lot of junk. I referred to How to get a contract's balance ...
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1answer
644 views

Web3 js proper way to call a Reading contract function

So i recently took over a project that had been abandoned for a while, which involves an ECR20 smart contract and the use of the web3 library to communicate with the smart contract. I've been trying ...
3
votes
1answer
137 views

keccak256 output is different on ruby vs javascript…?

Ruby ethereum libraries use: https://github.com/phusion/digest-sha3-ruby require 'digest/sha3' '0x' + Digest::SHA3.new(256).hexdigest('0x0') => "...
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1answer
329 views

How can I get the ABI from solc.compile? (^0.6.4)

In pragma solidity ^0.6.4; I wrote a contract and can get the byte code as follow: const solc = require("solc"); const path = require("path"); const fs = require("fs"); const inboxPath = path....
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1answer
226 views

How to listen to Metamask Ethereum events

I am trying to listen to the 'chainChanged' event for Metamask, but the event never fires. When running the following snippet, the I get a console.log of the chainId once, but the chainChanged event ...
0
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2answers
52 views

Transaction won't be mined / Failed signing of transaction

I'm trying to send a transaction that writes somesthing on ethereum(kovan) but it seems my transaction is not mined and probably not even send to the network? All my view requests to ethereum work, so ...
2
votes
0answers
381 views

Why ethers.js sign function not working?

I am using the ethers.js library, and am trying to code a transaction. Here is a snippet where I connect a wallet to a provider, connect to a contract I want to call a function in, and try to call the ...
0
votes
1answer
210 views

I'm getting “Cross-Origin Request Blocked” error

I'm getting this error: Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at http://localhost:8545/. (Reason: CORS request did not succeed). I'm aware ...
0
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1answer
526 views

Interact with smart contract without metamask

I'm writing an ethereum application that I want to use for an IoT demonstrator. I want to use MQTT to subscribe to an topic and as soon as a signal is transmitted to that topic I want to write ...
3
votes
2answers
317 views

Read message of require / revert statement in app.js

In my App.js I have called the smart contract function and the require statement in the function is not satisfied, so how do I get the message of that require statement in my App.js?
1
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1answer
34 views

Value of emitted events in App.js

Actually in my App.js I have called my contract function like this: [ this.state.swapcontract.methods.sendFunds(address).send({ from: this.state.account , value:amount}) ] The function is called ...
0
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0answers
26 views

How to get return value from a contract on JavaScript? [duplicate]

I am making a contract with a front-end made with JS, I studied myself how to make it work calling the functions with or without variables. But I don't know how to get the return value. I would ...
0
votes
1answer
150 views

Executing an contract via code and without metamask / link an account to JS code to automatically wirte on Ethereum

I'm trying to get my JS-code to call a smart contract on Ethereum (kovan testnet) that will write something on the blockchain and therefore needs ether (actually gas). I called a view function which ...
1
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0answers
110 views

Why won't my HTML file run/import my JS file?

My app.js file runs a node.js HTML server using nodemon app.js. I'm using fs.readFile to run index.html for the front-end. index.html file imports main.js using <script type="text/javascript" src="/...
1
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0answers
102 views

when iam runing npm run dev it showing me this error, how to solve this [closed]

[![shiva@shiva-VirtualBox:~/sta$ npm run dev StarNotary@1.0.0 dev /home/shiva/sta lite-server ** browser-sync config ** { injectChanges: false, files: [ './**/*.{html,htm,css,js}' ], ...
2
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2answers
213 views

How to decode a transaction to verify its signature in Javascript?

I noticed that it's possible to sign a transaction with a wrong private key. I took the following example found at https://github.com/ethereumjs/ethereumjs-tx const EthereumTx = require('ethereumjs-...
1
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0answers
70 views

ipfs with ethereum

Module not found: Can't resolve 'ipfs-api' in 'C:\Users.......\src' I have used this code //using the infura.io node, otherwise ipfs requires you to run a //daemon on your own computer/server. const ...
1
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0answers
410 views

UnhandledPromiseRejectionWarning TypeError when deploying multiple contracts (>200) at the same time

I get the following error: (node:6540) UnhandledPromiseRejectionWarning: TypeError: this.removeListener is not a function at Object.receipt (c:\Users\pruto\OneDrive\Documents\Smart contracts\...
2
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0answers
50 views

Confidential data encryption on blockchain

I already built a supply chain that is able to collect product information on Ethereum. Now, that data can be confidential, but I still want to do Matrix calculations on it. I came across homomorphic ...
2
votes
1answer
39 views

What is the easier way (no libraries, no 100KB of JavaScript) to read value from the blockchain?

I'm working on an open-source project. I'm hesitant to include web3.js with all the code. I just want to read a single value from the Ethereum blockchain. That is why my requirement is to avoid ...
0
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1answer
41 views

Different block information for the same block number at different times

On web3.eth.subscribe('newBlockHeaders') I get notification and trying to get last block via saved block number earlier. It was happen with 9559839 block number on mainnet. First, I was get data with ...

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