Axios is not defined : <p>I am using axios for building a simple weather app with React.js. I just completed the code but there is a problem. When I launch that app, it's not working at all and I see a reference error that says <code>axios is not defined</code>.</p>

<p>Here is my webpack.config.js file:</p>

<pre><code>module.exports = {
    entry: './public/app/app.jsx',
    output: {
        path: __dirname,
        filename: './public/js/bundle.js'
    },
    externals: ['axios'],
    resolve: {
        root: __dirname,
        alias: {
            OpenWeatherMap: 'public/components/OpenWeatherMap.jsx',
            Main: 'public/components/Main.jsx',
            Nav: 'public/components/Nav.jsx',
            Weather: 'public/components/Weather.jsx',
            WeatherForm: 'public/components/WeatherForm.jsx',
            WeatherMessage: 'public/components/WeatherMessage.jsx',
            About: 'public/components/About.jsx'
        },
        extensions: ['', '.js', '.jsx']
    },
    module: {
        loaders: [{
            loader: 'babel-loader',
            query: {
                presets: ['react','es2015', 'stage-0']
            },
            test: /\.jsx?$/,
            exclude: /(node_modules|bower_components)/
        },{
            loader: 'json-loader',
            test: /\.json?$/
        }]
    }
};
</code></pre>

<p>and package.json file:</p>

<pre><code>{
  "name": "weather",
  "version": "1.0.0",
  "description": "Simple Weather App",
  "main": "ext.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" &amp;&amp; exit 1"
  },
  "author": "Milad Fattahi",
  "license": "ISC",
  "dependencies": {
    "axios": "^0.16.1",
    "express": "^4.15.3",
    "json": "^9.0.6",
    "json-loader": "^0.5.4",
    "react": "^15.5.4",
    "react-dom": "^15.5.4",
    "react-router": "^4.1.1",
    "react-router-dom": "^4.1.1"
  },
  "devDependencies": {
    "babel-core": "^6.5.1",
    "babel-loader": "^6.2.2",
    "babel-preset-es2015": "^6.5.0",
    "babel-preset-react": "^6.5.0",
    "babel-preset-stage-0": "^6.24.1",
    "webpack": "^1.12.13"
  }
}
</code></pre>
