我在第一个React js应用程序中无法获取函数。

这是我的项目的结构：

hello-world
  -- app
     -- components
       -- main.jsx
  -- node_modules
  -- public
     -- build.js
     -- index.html
  -- package.json

这是我使用npm安装的内容：

npm install react react-dom babel-core babel-loader babel-preset-es2015    babel-preset-react webpack --save-dev
npm install --save isomorphic-fetch es6-promise

我使用webpack webpack.config

module.exports = {
  entry: './app/components/main.jsx',
  output: {
    path: './public/',
    filename: "build.js",
  },
  module: {
    loaders: [
      {
        exclude: /(node_modules|bower_components)/,
        loader: 'babel',
        query: {
          presets: ['es2015', 'react']
        }
      }
    ]
  }
};

package.json

{
  "name": "hello-world",
  "version": "1.0.0",
  "description": "",
  "main": "webpack.config.js",
  "scripts": {
    "build": "webpack -w"
  },
  "author": "mannuk",
  "license": "MIT",
  "devDependencies": {
    "babel-core": "^6.14.0",
    "babel-loader": "^6.2.5",
    "babel-preset-es2015": "^6.14.0",
    "babel-preset-react": "^6.11.1",
    "react": "^0.14.8",
    "react-dom": "^0.14.8",
    "webpack": "^1.13.2"
  },
  "dependencies": {
    "es6-promise": "^3.3.1",
    "isomorphic-fetch": "^2.2.1"
  }
}

这是我构建UI的文件：

main.jsx

import React from 'react';
import ReactDOM from 'react-dom';
import 'isomorphic-fetch';
import 'es6-promise';

class Person extends React.Component {

  constructor(props){
    super(props);
    this.state = {people : []};
  }

  componentWillMount(){
    fetch('xxx/people',
      method: 'get',
      headers: {'token' : 'xxx'}
      )
      .then((response) => {
        return response.json()
      })
      .then((people) => {
        this.setState({ people: people })
      })
  }

  render(){
    return <div>
        <input type="text" value={this.state.people[0].name}></input>
      </div>
  }
}

ReactDOM.render(
  <Person/>,
  document.getElementById('container')
);

如果我尝试通过浏览器运行它，它会失败（未定义获取方法），我还检查了此发布的ES6后版本“未定义获取”，并且包含的​​导入均未成功。我还包括es6-promise导入，但也失败了。

我究竟做错了什么？是配置问题还是什么？当我运行“ npm run build”时，没有错误，build.js似乎还可以。