create an ethereum account and store it in account.json

create.js

const fs = require('fs');
const Web3 = require('web3');
const web3 = new Web3("http://localhost:8545");

const filename = "account.json"
if (fs.existsSync(filename)) {
  console.log(filename+" already exists (delete it to create a new account)")
}else{
  let account = web3.eth.accounts.create();
  console.log(filename,account)
  fs.writeFileSync(filename,JSON.stringify(account))
}