错误：使用API​​获取数据时未定义属性

Question

在我的程序中，我从github API获取一些用户数据并更新状态，但是我收到一个错误，即无法读取未定义的属性。直到最后一点，一旦我添加了新数据，我就收到了错误。下面是我的代码和错误的屏幕截图。任何帮助，将不胜感激。

错误::

代码：

api.js

import axios from 'axios';

var id = "YOUR_CLIENT_ID";
var sec = "YOUR_SECRET_ID";
var params = "?client_id=" + id + "&client_secret=" + sec;

function getProfile (username) {
  return axios.get('https://api.github.com/users/' + username + params)
    .then(function (user) {
      return user.data;
    });
}

function getRepos (username) {
  return axios.get('https://api.github.com/users/' + username + '/repos' + params + '&per_page=100');
}

function getStarCount (repos) {
  return repos.data.reduce(function (count, repo) {
    return count + repo.stargazers_count
  }, 0);
}

function calculateScore (profile, repos) {
  var followers = profile.followers;
  var totalStars = getStarCount(repos);

  return (followers * 3) + totalStars;
}

function handleError (error) {
  console.warn(error);
  return null;
}

function getUserData (player) {
  return axios.all([
    getProfile(player),
    getRepos(player)
  ]).then(function (data) {
    var profile = data[0];
    var repos = data[1];

    return {
      profile: profile,
      score: calculateScore(profile, repos)
    }
  });
}

function sortPlayers (players) {
  return players.sort(function (a,b) {
    return b.score - a.score;
  });
}

export default {
  battle: function (players) {
    return axios.all(players.map(getUserData))
      .then(sortPlayers)
      .catch(handleError);
  },

  fetchPopularRepos: function (language) {
    var encodedURI = window.encodeURI('https://api.github.com/search/repositories?q=stars:>1+language:'+ language + '&sort=stars&order=desc&type=Repositories');

    return axios.get(encodedURI)
      .then(function (response) {
        return response.data.items;
      });
  }
};

Results.js

import React from 'react';
import queryString from 'query-string';
import api from '../utils/api';
import { Link } from 'react-router-dom';
import PropTypes from 'prop-types';
import PlayerPreview from '../Components/PlayerPreview';

function Profile (props) {
  var info = props.info;
  console.log(info);
  return(
    <PlayerPreview avatar={info.avatar_url} username={info.login}>
      <ul className='space-list-items'>
        {info.name && <li>{info.name}</li>}
        {info.location && <li>{info.location}</li>}
        {info.company && <li>{info.company}</li>}
        <li>Followers: {info.followers}</li>
        <li>Following: {info.following}</li>
        <li>Public Repos: {info.public_repos}</li>
        {info.blog && <li><a href={info.blog}>{info.blog}</a></li>}
      </ul>
    </PlayerPreview>
  )
}

Profile.propType = {
  info: PropTypes.object.isRequired  
}

function Player (props) {
   return (
      <div>
         <h1 className='header'> {props.label} </h1>
         <h3 style={{textAlign: 'center'}}> Score: {props.score} </h3>
         <Profile info={props.profile}/>
      </div>
   )
}

Player.propTypes = {
   label: PropTypes.string.isRequired,
   score: PropTypes.number.isRequired,
   profile: PropTypes.object.isRequired
}

class Results extends React.Component {
   constructor(props) {
      super(props);

      this.state = {
         winner: {},
         loser: {},
         error: null,
         loading: true
      }
   }

   componentDidMount() {
    var players = queryString.parse(this.props.location.search);

    api.battle([
      players.playerOneName,
      players.playerTwoName
    ]).then(function (players){
      if (players === null) {
        return this.setState(function () {
          return {
            error: 'Looks like there was an error. Check that both users exist on Github.',
            loading: false,
          }
        });
      }

      this.setState(function () {
        return {
          error: null,
          winner: players[0],
          loser: players[1],
          loading: false,
        }
      });
    }.bind(this));
   }

   render () {
      var error = this.state.error;
      var winner = this.state.winner;
      var loser = this.state.loser;
      var loading = this.state.loading;

      if(loading === true){
         <p> Loading !! </p>
      }

      if (error) {
        return (
          <div>
            <p>{error}</p>
            <Link to='/battle'>Reset</Link>
          </div>
        )
      }

      return (
        <div className='row'>
          <Player
            label='Winner'
            score={winner.score}
            profile={winner.profile}
          />
          <Player
            label='Loser'
            score={loser.score}
            profile={loser.profile}
          />
        </div>
      )
    }
}

export default Results;

PlayerPreview.js

import React from 'react';
import PropTypes from 'prop-types';

function PlayerPreview (props) {
   return (
     <div>
       <div className='column'>
         <img
           className='avatar'
           src={props.avatar}
           alt={'Avatar for ' + props.username}
         />
         <h2 className='username'>@{props.username}</h2>
       </div>
       {props.children}
     </div>
   )
 }

 PlayerPreview.propTypes = {
   avatar: PropTypes.string.isRequired,
   username: PropTypes.string.isRequired,
 };

 export default PlayerPreview;