web3简单整合react系列-发起交易(三)

1、app.js

import logo from './logo.svg';
import './App.css';
//import './polyfill.js';
import Web3 from 'web3';
import React, {useEffect, useState} from 'react';
import {init, mintToken} from './Web3Client'
function App() {
 
  const [minted, setMinted] = useState(false);
 
  const mint = () =>{
    mintToken().then((tx) =>{
      console.log(tx);
      setMinted(true);
    }).catch((err) => {
       console.log(err);
    });
  };
 
 
  return <div className='App'>
 
    {
      !minted
      ?<button onClick={() => mint()}>Mint token</button> 
      :<p>Token minted successfully!</p>
     }
  </div>;
}
 
export default App;

2、web3clint

import Web3 from 'web3';
import TestTokenContractBuild from 'contracts/TestToken.json';

let selectedAccount;

let testTokenContract;

let isInitialized = false;
//'../truffle/build/contracts/TestToken.json';
export const init = async () => {
    let provider = window.ethereum;



    if(typeof provider !== 'undefined'){
      provider
      .request({method: 'eth_requestAccounts'})
      .then(accounts =>{
        selectedAccount =  accounts[0];
        console.log(`Selected Account is ${selectedAccount}$`);
      }).catch((err)=>{
        console.log(err);
      }); 
      // 监听metamask 账号改变
      window.ethereum.on('accountsChanged', function(accounts){
          selectedAccount = accounts[0];
         console.log(`Selected Account is ${selectedAccount}$`);
      });
    }
    const web3 = new Web3(provider);
    const networkId = await web3.eth.net.getId();

    testTokenContract = new web3.eth.Contract(
        TestTokenContractBuild.abi,
        //TestTokenContractBuild.networks[networkId].address
        '0x15ab7f6ADF501971fdC5AEb4934a52A20104f8A2'
        );

    isInitialized =     true;
};

export const mintToken = async () => {

    if(!isInitialized) {
        await init();
    }

   return testTokenContract.methods
   .mint(selectedAccount)
   .send({from:selectedAccount} );
};