Questions tagged [react]

React (also known as React.js or ReactJS) is a JavaScript library for building user interfaces. It uses a declarative paradigm and aims to be both efficient and flexible.

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web3.eth.accounts.wallet.create() works on desktop Chrome but not on mobile

The following lines of code work (a generator function of redux-saga in my React app) on desktop Chrome. However, it does not work on desktop Safari, iOS, and mobile Chrome (on Android). Did not works ...
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1answer
25 views

Error when retrieving the instance of a deployed contract

I have developed a EnergyExchange DApp in the Ganache local network with React that consist of one main contract "EnergyExchange". This main contract has a function to deploy new Agent ...
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Error when calling a get function from a deployed contract instance

I have developed a EnergyExchange DApp in the Ganache local network with React that consist of one main contract "EnergyExchange". This main contract has a function to deploy new Agent ...
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27 views

How to connect local private geth nodes to the web page without using metamask or mist?

I'm developing a web wallet similar to meta mask that can make transactions or can create accounts from UI. Frontend is developed using React. Blockchain is implemented in geth.I'm using truffle react ...
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1answer
78 views

How to save the contract instance on a mapping in solidity?

I have created an EnergyExchange contract in my React app.js that it is deployed in the network. Inside the EnergyExchange contract there is a function to create Agent contracts. What I am trying to ...
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111 views

My Crowdsale contract wont transfer ERC20 tokens and all transactions fail

I have a crowdsale contract that recieves tokens directly from a mint function in my token contract.the function mints the tokens and sends its to the Crowdsale account address. when I run let token = ...
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1answer
59 views

where to host my react fornt end and express endpoint that interact with smart contract to be fully decentralised?

where to host my react fornt end and express endpoint that interact with smart contract to be fully decentralised. Are there any option to host it decentralised any cloud provider other than ...
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27 views

Array lenght and data miss match while storing data of events

Can someone help me in finding what is wrong here a why the length of task info is 0 even the taskInfo has some data. I'm using events to fill the taskinfo array. I'm stuck at this place for almost 2 ...
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2answers
381 views

Trying to connect front-end application with smart contract

I am creating a simple registration and login forms in React.js and connecting it with smart contract in order to use it to store the data from the front and to the blockchain is there any method or ...
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2answers
45 views

Call and Save Returned Value from Method in React

I am trying to call a method from my smart contract (myMethod) and save the result (result) as a state (this.state.result) in react. However, my state is not being updated to the result. My code is ...
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1answer
108 views

Accessing array within struct in a mapping using web3.js

I have created a struct patient as follows, and a mapping of uint->patient. struct patient { uint pId; string name; string phone; address payable owner; uint numRecords; uint[]...
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How do I get a structure of a mapping inside a structure?

So. I started using too many mappings. Now I'm not sure how to get the information on the front: struct Demand{ uint remuneration; uint delay; uint deadline; string description; ...
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1answer
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solidity function works perfectly in remix but in react application it is not executing in the same way

in Remix i execute it and it works as i expecting and when i check the value from other function it returns the expecting value function makeadmin(string memory cityN, address adminAdress, string ...
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40 views

Error while unboxing trufle react

gyp ERR! build error gyp ERR! stack Error: `C:\Program Files (x86)\Microsoft Visual Studio\2017\BuildTools\MSBuild\15.0\Bin\MSBuild.exe` failed with exit code: 1 gyp ERR! stack at ChildProcess....
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2answers
14 views

Calling Contract Function

I am trying to call a function from my back-end to my front-end. I know that my contract is deploying, however, I don't think my function is not being called correctly. My code is provided below. Does ...
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2answers
92 views

Deploying a Contract vs. Instantiating a Contract

I apologize for the very basic question but I am a little confused. What is the difference between deploying a contract and instantiating a contract?
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1answer
27 views

Deploying Contract with React

I am trying to deploy a contract on react. But I can't seem to pull it off :( This is my code: this.myContract.deploy({ data:[big boi bytecode here], arguments: ['name', '...
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29 views

Truffle Object Keeps Changing to Undefined When I Try To Play With Data With React

The question is in the title. I have a React Component that displays the appropriate data when I do it in a very specific way, but breaks when I try to play with the data. state = { dataKey: "1",...
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2answers
29 views

mapp values do not upadte when calling other functions after populating the map

I am using react as my front end to call functions from smart contract . this is the front end where i call the functions. However, after calling the first function which populates the map I then ...
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1answer
880 views

npm ERR! code ENOENT npm ERR! syscall spawn git

I use the command npx truffle unbox react to develop a dapp but I get these errors below in my console. Can anybody help me? I really don't know how can I solve them.
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1answer
45 views

How do I fix it? To be able to send eth from smartcontract to the address

Frontend class App extends React.Component { state = { address: '', } async componentDidMount() { await window.ethereum.enable() this.w3 = new Web3(window.ethereum) const ...
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What do I have to do to call this events to be display on the web page?

How do I call showLottery to display on my webpage? Front-End class App extends React.Component { state = { address: '', lottery: '', events: '', } async componentDidMount() { ...
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95 views

getPastEvents undefined(please help)

I had asked this question before. I looked carefully at the exchange section, which I advised, and I think there is no problem with the exchange section. At least in my opinion there is no problem and ...
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1answer
38 views

TypeError: market.FileViewed is not a function while trying to watch event

I want to watch for fileViewed event and it throws TypeError: market.FileViewed is not a function in marketplace.FileViewed{ ^ My solidity contract: pragma solidity ^0.5.0; contract ...
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1answer
178 views

“drizzle-react-components” import Error for “LoadingContainer”

I am trying to import import { LoadingContainer } from 'drizzle-react-components' Which I succfully installed with npm install drizzle-react-components@1.3.0 It was installed inside the directory ...
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1answer
71 views

Contract with multiple signing keys

How things work I have a Factory contract, FContract. FContract can be called by a user as many times as they want, creating instances of, let's call it, contractA. Thus, they're able to own as many ...
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80 views

Payable function not working properly

Hi everyone hope I will be clear enough with the explanation because I couldn't find a proper solution. I am just trying to checkout an item with my buy function but it seems like I am stuck.Here is ...
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1answer
551 views

Code:const web3 = new Web3(window.web3.currentProvider) Error: window.web3 is undefined

I am going to connect my contract with the website.However,there was something wrong with the web3? I'm not sure. import Web3 from "web3"; const web3 = new Web3(window.web3.currentProvider); const ...
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1answer
484 views

Event emits multiple times on a solidity function call

I need have a problem, when I execute a solidity function, event emits multiple times, but when I refresh page then it works normally and only past events get called. Here is my code: ...
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83 views

uncaught error:invalid address

Uncaught (in promise) Error: invalid address at inputAddressFormatter (formatters.js:271) at inputTransactionFormatter (formatters.js:97) at method.js:89 at Array.map (<anonymous>...
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1answer
144 views

How to print “string” from Solidity in React?

My smart contract function is : function sNName(uint z)public view returns(string memory) { return abc[xyz[z].name]; } Where abc represents a mapping (bytes32 => string) In my .js file, I ...
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370 views

How to get the value from the frontend form and save value to the blockchain using +web3 1.0.0-beta.37 + reactjs

I am writing my first Dapp and want to save the value of the form to the blockchain. I am Using React and web3 js 1.0.0-beta.37 on the frontend. Also I am new to react. Following is my App.js ...
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2answers
514 views

No “from” address specified in neither the specified in neither the given options nor the default options

So I already went through this query, but I still couldn't get my doubt solved. Be it any Blockchain Dapp, the same error is coming for me. I used the marriage certificate and kickstart examples. Can ...
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1answer
112 views

web3-core-method.umd.js:1191 Uncaught (in promise) Error: Transaction has been reverted by the EVM:

Keep getting this error and really not sure what's causing it. Smart contract: contract BasaltStore { // struct of how a document will be stored struct documentStore { // unique id of the ...
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84 views

Store data on ethereum block chain using react js

I'm trying to store data on ethereum blockchain by doing this import storemetadata from "./storemetadata"; where i have the smart contract ABI in storemetadata I now add name like so storemetadata....
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426 views

address.replace is not a function

I'm not really sure why this web3 method is being called in my code and why it's not a function apparently. Can anyone help me understand what the issue is here? Unhandled Rejection (TypeError): ...
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96 views

Release / Debug build generated json-rpc calls are different

I'm trying to make simple web3 calls in React Native with web3.js, but generated json-rpc calls are different between release / debug builds - IOS/Xcode. Expected behavior const web3 = new Web3(`...
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407 views

Web3 is injecting but stilling getting an invalid provider error

I'm injecting web3 with MetaMask, and everything works, but when I make a production build, I notice that it injects web3 alright, but when I try to call a web3 function, it throws `Please provide an ...
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1answer
516 views

Unhandled Rejection (Error): invalid string value (arg=“x”, coderType=“string”, value=5)

Using Truffle unbox react to unbox a boilerplate. received the following error from running npm run start Changes: Addition of "memory" parameters in the simpleStorage.sol Changed unit to string in ...
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1answer
207 views

How to send context from DrizzleContext.Provider to a Class Component / Class Container

I'm using the new Context API supported 'drizzle-react' library in my dapp. Can anyone please clarify how to receive the context sent from DrizzleContext.Provider into a "class" component? Check out ...
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1answer
3k views

Could not find “store” in either the context or props of “Connect(c)”. Either wrap the root component in a <Provider>

i'm trying to create a drizzle-react app which uses the new DrizzleContext component but running the following error in my 'localhost:3000': > Could not find "store" in either the context or ...
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0answers
131 views

solc/wrapper not working with reactjs

My compile.js code: var wrapper = require('solc/wrapper') var solc = wrapper(window.Module) const Compile = (code,name) => { return solc.compile(code, 1).contracts[':'+name]; }; export default ...
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1answer
387 views

Using web3.js in a react redux saga app - uncaught at check call error

I am trying to use Web3.js (Ethereum JavaScript API) in a ReactJS app with Redux / Saga. This is my GetWeb3 function: const GetWeb3 = () => new Promise((resolve, reject) => { window....
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1answer
573 views

How to write a component in Drizzle React? [closed]

The components are for the following functions: function tokenURI(uint256 _tokenId) public view returns (string) { require(exists(_tokenId)); return tokenURIs[_tokenId]; } function ...
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1answer
884 views

React/Truffle: How to call a function with passing a variable?

I have a React component within which a web3js function queries numbers from Ethereum by using getNumber() function. I want to call another function called setNumber() that takes one uint256, by ...
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1answer
65 views

React returns Error 'TypeError: ETHEREUM_CLIENT.eth.contract is not a function' when I trying to connect to my ethereum contract

I declared the variables as follows import React, { Component } from 'react'; import logo from './logo.svg'; import './App.css'; import Web3 from 'web3'; var ETHEREUM_CLIENT = new Web3(new Web3....
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1answer
479 views

Accessing Web3 in trufflebox's react-auth-box

Hi I am using trufflebox boilerplate react-auth-box. Created a new component called Foo where I am trying to access the web3 object that has been mapped from Store to this.props. However the console....

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