babel.rc

{
  presets: ["env", "react"]
}

package.json

{
  "name": "pokemon",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "build": "webpack"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "dependencies": {
    "react": "^16.4.2",
    "react-dom": "^16.4.2",
    "webpack": "^4.17.1"
  },
  "devDependencies": {
    "@babel/preset-env": "^7.0.0-rc.2",
    "webpack-cli": "^3.1.0"
  }
}

webpack.config.js

const path = require("path");

module.exports = {
  output: {
    path: __dirname + "/dist",
    filename: "bundle.js"
  },
  entry: "./src/index.js",
  module: {
    rules: [
      { 
        test: /\.js$/,
        exclude: /node_modules/,
        query: require("./babel.rc"),
        loader: "babel-loader"
      }
    ]
  },
  mode: "development"
};