如何使用Webpack 4进行ES6导入/导出?

时间:2018-03-11 19:54:58

标签: webpack es6-modules webpack-4

我正在尝试使用基于Web6 4的基本ES6 import / export,而Webpack似乎无法解析我的模块,尽管根据错误信息,它看起来正确:

$ make
./node_modules/.bin/webpack --mode production src/app.js -o dist/bundle.js
Hash: 6decf05b399fcbd42b01
Version: webpack 4.1.1
Time: 339ms
Built at: 2018-3-11 14:50:58
 1 asset
 Entrypoint main = bundle.js
    [0] ./src/app.js 41 bytes {0} [built]

ERROR in ./src/app.js
Module not found: Error: Can't resolve 'hello.js' in '/home/(myhomedir)/code/js/src'
 @ ./src/app.js 1:0-31 2:0-5                                    

这是我的设置(node_modulesdist等省略):

$ npm ls --depth=0
.
├── webpack@4.1.1
└── webpack-cli@2.0.11

$ tree
.
├── Makefile
└── src
    ├── app.js
    └── hello.js

生成文件:

webpack = ./node_modules/.bin/webpack --mode production
entry = src/app.js

webpack: $(entry)
    $(webpack) $(entry) -o dist/bundle.js

的src / app.js:

import {hello} from "hello.js";
hello();

的src / hello.js:

function hello() {
    alert("yes it's hello");
}
export { hello };

我在app.js的导入路径上尝试了很多变体,但它们都得到了相同的结果:Can't resolve模块文件。我错过了什么?

2 个答案:

答案 0 :(得分:4)

你需要使用babel& amp;使用babel-loader

此外,您不需要使用制作,只需使用 npm脚本

导入import { hello } from 'hello.js'等错误应该是import { hello } from './hello.js'或没有 .js ,例如import { hello } from './hello'

尝试以下方法 -

npm install --save-dev babel-core babel-loader babel-preset-env webpack @ next webpack-cli

的src / app.js

import { hello } from "./hello";
hello();

的src / hello.js

function hello() {
  console.log("yes it's hello");
}
export { hello };

webpack.config.js

const path = require("path");

module.exports = {
  entry: "./src/app.js",

  output: {
    path: path.resolve(__dirname, "dist"),
    filename: "bundle.js"
  },

  module: {
    rules: [
      {
        test: /\.js$/,
        loader: "babel-loader",
        exclude: /(node_modules)/
      }
    ]
  }
};

的package.json

{
  "name": "webpack-test",
  "version": "1.0.0",
  "description": "",
  "main": "webpack.config.js",
  "scripts": {
    "build": "webpack --mode development",
    "prod": "webpack --mode production",
    "start": "node dist/bundle.js"
  },
  "keywords": [],
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "babel-core": "^6.26.0",
    "babel-loader": "^7.1.4",
    "babel-preset-env": "^1.6.1",
    "webpack": "^4.0.0-beta.3",
    "webpack-cli": "^2.0.11"
  }
}

.babelrc

{
  "presets": ["env"]
}

首次运行npm run buildnpm run prod&然后运行npm run start,这将记录输出

答案 1 :(得分:0)

现代的解决方案是使用node.js 13+,然后将"type": "module"添加到package.json文件中。这将允许您使用导入语法而不是require。更多信息,请点击https://nodejs.org/dist/latest-v13.x/docs/api/esm.html

Webpack仍然需要require语法,因此您必须将webpack.config.js重命名为webpack.config.cjs,然后通过将webpack --config webpack.config.cjs添加到package.json脚本中,让Webpack知道新的配置文件是什么。命令。如果webpack修复了require的问题,请密切注意https://github.com/webpack/webpack-cli/issues/1165

这意味着您不需要任何通行证或翻译机。