Truffle - ожидаемый параметр 'solc' не передан в функцию

Question

У меня есть эта ошибка:

.../node_modules/truffle-expect/index.js:3
    expected_keys.forEach(function(key) {
                  ^
Error: Expected parameter 'solc' not passed to function.

, когда я пытаюсь использовать загрузчик трюфелей с помощью веб-пакета.Есть идеи как это исправить?Спасибо.

ОБНОВЛЕНИЕ :

Умный контракт:

pragma solidity ^0.5.0;

contract ToDo {
  struct Task {
    uint id;
    uint date;
    string content;
    string author;
    bool done;
  }

  uint lastTaskId;
  mapping(uint => Task) tasks;
  uint[] taskIds;

  constructor () public{
    lastTaskId = 0;
  }

  event TaskCreated(uint id, uint date, string content, string author, bool done);

  function createTask(string memory _content, string memory _author) public {
    lastTaskId++;
    tasks[lastTaskId] = Task(lastTaskId, now, _content, _author, false);
    taskIds.push(lastTaskId);
    emit TaskCreated(lastTaskId, now, _content, _author, false);
  }

  function getTask(uint id) taskExists(id) public view returns (uint, uint, string memory, string memory, bool) {
    return(
      id, 
      tasks[id].date,
      tasks[id].content,
      tasks[id].author,
      tasks[id].done
    );
  }

  function getTaskIds() view public returns (uint[] memory) {
    return taskIds;
  }

  // function getTaskFixtures(uint _id) public view returns(uint,uint,string,string,bool) {
  //   return (0, now, "Create more tutorials for ETB", "Julien", false); 
  // }

  modifier taskExists(uint id){
    if(tasks[id].id == 0){
      revert();
    }
    _;
  }
}

Index.js:

import artifact from '../../contracts/ToDo.sol';
import Web3 from 'web3';
import TruffleContract from 'truffle-contract';
// import config from './config.js';

console.log('loaded');

const web3 = new Web3(new Web3.providers.HttpProvider('http://localhost:7545'));

const abstraction = new TruffleContract(artifact);
abstraction.setProvider(web3.currentProvider);

const network = Object.keys(artifact.networks)[0];
const address = artifact.networks[network].address;

abstraction.at(address)
  .then((todo) => {
    todo.getTaskIds()
      .then((taskIds) => {
        console.log(taskIds);
      });
  });

web3.eth.getAccounts(console.log);

сервер:

const express = require('express');
const app = express();
const PORT = 3000;

//Serve static assets (js, css, ...)
app.use(express.static('app'));

//Serve contract artifact files (ex: ToDo.json)
app.use(express.static('build/contracts'));

//Serve index.html
app.get('/', (req, res) => {
  res.sendFile(`${__dirname}/app/index.html`);
});

//If anything else is requested that's an error
app.get('*', (req, res) => {
  res.status(404);
  res.send('Oops... this URL does not exist');
});

//Start the server
app.listen(PORT, () =>  {
  console.log(`ETB Ethereum ToDo List App running on port ${PORT}...`);
});

xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx