js/main.js

import * as aliasPerson from "./person.js";
import defaultPerson from "./person.js";
console.log("alias person is below ...");
console.log(aliasPerson);
console.log(aliasPerson.prototype);
console.log("default person is below ...");
console.log(defaultPerson);
console.log(defaultPerson.prototype);

js/person.js

function Person(){}
Person.nickname = "this is a person";
Person.birthday = "1900-01-01";
Person.prototype.eat = function(){};
module.exports = Person;

webpack.config.js

var entryFilePath = "./js/main.js";

var webpackConfig = {
   entry: entryFilePath,
   output: {
      filename: "result.js"
   },
   module: {
      // rules: [{test: /\.js$/,loader: 'babel-loader'}] 
   }
};
module.exports = webpackConfig;

.babelrc

{
  "presets": [
      "es2015",
      "stage-3"
    ],
    "plugins": [
      ["transform-runtime",
        {
          "helpers": false,
          "polyfill": false,
          "regenerator": true,
          "moduleName": "babel-runtime"
        }]
    ]
}

package.json

{
    "scripts": {
        "build": "webpack"
    },
    "devDependencies": {
        "babel-core": "^6.26.3",
        "babel-loader": "^7.1.4",
        "babel-plugin-transform-runtime": "^6.23.0",
        "babel-preset-es2015": "^6.24.1",
        "babel-preset-stage-3": "^6.24.1",
        "babel-runtime": "^6.26.0",
        "webpack": "^3.10.0",
        "webpack-dev-server": "^2.9.7"
    }
}

一 不使用babel做轉義

直接執行 npm run build 生成result.js

執行 node result.js

import * as aliasPerson from "./person.js";

import defaultPerson from "./person.js";

執行結構完全一樣

二 使用babel做轉義

取消如下註釋.

執行 npm run build 生成result.js

執行 node result.js

使用 import * as aliasPerson from "./person.js";

多了 一個default屬性，並且 aliasPerson.prototype 為 undefined

原因如下

import * as aliasPerson from "./person.js";

當引入的 ./person.js 模塊不為es 模塊的時候(obj.__esModule === false)

babel會將 module.exports 所指向的對象的非繼承屬性遍歷並附加到 newObj對象中，

並且 newObj.default = module.exports

webpack與babel解析module.exports差異