node.js - 找不到模块 : Error: Cannot resolve module 'module' mongodb while bundling with webpack

Question

当我尝试在我的 Node 应用程序中使用 mongoose connect 时，Webpack 抛出以下错误。

最初还有几个错误，例如，

Module not found: Error: Cannot resolve module 'fs' 

在我的 webpack 配置文件中进行以下更改就可以了，

• 我在我的 webpack 配置文件中添加了 node-loader 和 node 对象。

  Node :{ 控制台:'空'， fs:'空'， 净:'空'， tls:'空'},

但是下面的错误仍然存​​在。知道如何解决吗？

WARNING in ./~/mongoose/~/mongodb/~/mongodb-core/~/require_optional/index.js
Critical dependencies:
63:18-42 the request of a dependency is an expression
71:20-44 the request of a dependency is an expression
78:35-67 the request of a dependency is an expression
 @ ./~/mongoose/~/mongodb/~/mongodb-core/~/require_optional/index.js 63:18-42 71:20-44 78:35-67

WARNING in ./~/mongoose/~/mongodb/~/mongodb-core/~/require_optional/README.md
Module parse failed: /Users/nitesh/Documents/learnReact/day1/r3-foundation-boilerplate/node_modules/mongoose/node_modules/mongodb/node_modules/mongodb-core/node_modules/require_optional/README.md Unexpected character '#' (1:0)
You may need an appropriate loader to handle this file type.
SyntaxError: Unexpected character '#' (1:0)
    at Parser.pp.raise (/Users/nitesh/Documents/learnReact/day1/r3-foundation-boilerplate/node_modules/webpack/node_modules/acorn/dist/acorn.js:920:13)
    at Parser.pp.getTokenFromCode (/Users/nitesh/Documents/learnReact/day1/r3-foundation-boilerplate/node_modules/webpack/node_modules/acorn/dist/acorn.js:2813:8)
    at Parser.pp.readToken (/Users/nitesh/Documents/learnReact/day1/r3-foundation-boilerplate/node_modules/webpack/node_modules/acorn/dist/acorn.js:2508:15)
    at Parser.pp.nextToken (/Users/nitesh/Documents/learnReact/day1/r3-foundation-boilerplate/node_modules/webpack/node_modules/acorn/dist/acorn.js:2500:71)
    at Parser.parse (/Users/nitesh/Documents/learnReact/day1/r3-foundation-boilerplate/node_modules/webpack/node_modules/acorn/dist/acorn.js:1615:10)
    at Object.parse (/Users/nitesh/Documents/learnReact/day1/r3-foundation-boilerplate/node_modules/webpack/node_modules/acorn/dist/acorn.js:882:44)
    at Parser.parse (/Users/nitesh/Documents/learnReact/day1/r3-foundation-boilerplate/node_modules/webpack/lib/Parser.js:902:15)
    at DependenciesBlock.<anonymous> (/Users/nitesh/Documents/learnReact/day1/r3-foundation-boilerplate/node_modules/webpack/lib/NormalModule.js:104:16)
    at DependenciesBlock.onModuleBuild (/Users/nitesh/Documents/learnReact/day1/r3-foundation-boilerplate/node_modules/webpack/node_modules/webpack-core/lib/NormalModuleMixin.js:310:10)
    at nextLoader (/Users/nitesh/Documents/learnReact/day1/r3-foundation-boilerplate/node_modules/webpack/node_modules/webpack-core/lib/NormalModuleMixin.js:275:25)
 @ ./~/mongoose/~/mongodb/~/mongodb-core/~/require_optional ^\.\/.*$

WARNING in ./~/mongoose/~/mongodb/~/mongodb-core/~/require_optional/LICENSE
Module parse failed: /Users/nitesh/Documents/learnReact/day1/r3-foundation-boilerplate/node_modules/mongoose/node_modules/mongodb/node_modules/mongodb-core/node_modules/require_optional/LICENSE Unexpected token (1:40)
You may need an appropriate loader to handle this file type.
SyntaxError: Unexpected token (1:40)
    at Parser.pp.raise (/Users/nitesh/Documents/learnReact/day1/r3-foundation-boilerplate/node_modules/webpack/node_modules/acorn/dist/acorn.js:920:13)
    at Parser.pp.unexpected (/Users/nitesh/Documents/learnReact/day1/r3-foundation-boilerplate/node_modules/webpack/node_modules/acorn/dist/acorn.js:1483:8)
    at Parser.pp.semicolon (/Users/nitesh/Documents/learnReact/day1/r3-foundation-boilerplate/node_modules/webpack/node_modules/acorn/dist/acorn.js:1462:73)
    at Parser.pp.parseExpressionStatement (/Users/nitesh/Documents/learnReact/day1/r3-foundation-boilerplate/node_modules/webpack/node_modules/acorn/dist/acorn.js:1976:8)
    at Parser.pp.parseStatement (/Users/nitesh/Documents/learnReact/day1/r3-foundation-boilerplate/node_modules/webpack/node_modules/acorn/dist/acorn.js:1754:188)
    at Parser.pp.parseTopLevel (/Users/nitesh/Documents/learnReact/day1/r3-foundation-boilerplate/node_modules/webpack/node_modules/acorn/dist/acorn.js:1648:21)
    at Parser.parse (/Users/nitesh/Documents/learnReact/day1/r3-foundation-boilerplate/node_modules/webpack/node_modules/acorn/dist/acorn.js:1616:17)
    at Object.parse (/Users/nitesh/Documents/learnReact/day1/r3-foundation-boilerplate/node_modules/webpack/node_modules/acorn/dist/acorn.js:882:44)
    at Parser.parse (/Users/nitesh/Documents/learnReact/day1/r3-foundation-boilerplate/node_modules/webpack/lib/Parser.js:902:15)
    at DependenciesBlock.<anonymous> (/Users/nitesh/Documents/learnReact/day1/r3-foundation-boilerplate/node_modules/webpack/lib/NormalModule.js:104:16)
 @ ./~/mongoose/~/mongodb/~/mongodb-core/~/require_optional ^\.\/.*$

ERROR in ./~/mongoose/~/mongodb/~/mongodb-core/~/require_optional/~/resolve-from/index.js
Module not found: Error: Cannot resolve module 'module' in /Users/nitesh/Documents/learnReact/day1/r3-foundation-boilerplate/node_modules/mongoose/node_modules/mongodb/node_modules/mongodb-core/node_modules/require_optional/node_modules/resolve-from
 @ ./~/mongoose/~/mongodb/~/mongodb-core/~/require_optional/~/resolve-from/index.js 3:13-30
Child extract-text-webpack-plugin:
    chunk    {0} extract-text-webpack-plugin-output-filename 221 kB [rendered]
        [0] ./~/css-loader!./~/postcss-loader!./src/styles/app.css 219 kB {0} [built]
        [1] ./~/css-loader/lib/css-base.js 1.51 kB {0} [built]
Child extract-text-webpack-plugin:
    chunk    {0} extract-text-webpack-plugin-output-filename 8.56 kB [rendered]
        [0] ./~/css-loader!./~/postcss-loader!./src/styles/styles.css 7.06 kB {0} [built]
        [1] ./~/css-loader/lib/css-base.js 1.51 kB {0} [built]
Child extract-text-webpack-plugin:
    chunk    {0} extract-text-webpack-plugin-output-filename 7.92 kB [rendered]
        [0] ./~/css-loader!./~/postcss-loader!./src/styles/slider.css 6.42 kB {0} [built]
        [1] ./~/css-loader/lib/css-base.js 1.51 kB {0} [built]
Child extract-text-webpack-plugin:
    chunk    {0} extract-text-webpack-plugin-output-filename 234 kB [rendered]
        [0] ./~/css-loader!./~/postcss-loader!./src/styles/app_override.css 232 kB {0} [built]
        [1] ./~/css-loader/lib/css-base.js 1.51 kB {0} [built]
Child extract-text-webpack-plugin:
                                     Asset     Size  Chunks       Chunk Names
      404a525502f8e5ba7e93b9f02d9e83a9.eot  75.2 kB               
    926c93d201fe51c8f351e858468980c3.woff2  70.7 kB               
     891e3f340c1126b4c7c142e5f6e86816.woff  89.1 kB               
      fb650aaf10736ffb9c4173079616bf01.ttf   151 kB               
      bae4a87c1e5dff40baa3f49d52f5347a.svg   386 kB               
    chunk    {0} extract-text-webpack-plugin-output-filename 41.4 kB [rendered]
        [0] ./~/css-loader!./~/postcss-loader!./src/styles/index.css 264 bytes {0} [built]
        [1] ./~/css-loader/lib/css-base.js 1.51 kB {0} [built]
        [2] ./~/css-loader!./~/font-awesome/css/font-awesome.css 39.1 kB {0} [built]
        [3] ./~/font-awesome/fonts/fontawesome-webfont.eot 82 bytes {0} [built]
        [4] ./~/font-awesome/fonts/fontawesome-webfont.eot?v=4.6.1 82 bytes {0} [built]
        [5] ./~/font-awesome/fonts/fontawesome-webfont.woff2?v=4.6.1 84 bytes {0} [built]
        [6] ./~/font-awesome/fonts/fontawesome-webfont.woff?v=4.6.1 83 bytes {0} [built]
        [7] ./~/font-awesome/fonts/fontawesome-webfont.ttf?v=4.6.1 82 bytes {0} [built]
        [8] ./~/font-awesome/fonts/fontawesome-webfont.svg?v=4.6.1 82 bytes {0} [built]
Child extract-text-webpack-plugin:
    chunk    {0} extract-text-webpack-plugin-output-filename 88.8 kB [rendered]
        [0] ./~/css-loader!./~/postcss-loader!./~/sass-loader?outputStyle=expanded!./src/styles/foundation.scss 87.3 kB {0} [built]
        [1] ./~/css-loader/lib/css-base.js 1.51 kB {0} [built]
Module not found: Error: Cannot resolve module 'module' mongodb

webpack.config.js

var path = require('path')
var webpack = require('webpack')
var autoprefixer = require('autoprefixer')
var ExtractTextPlugin = require('extract-text-webpack-plugin')

var assetPath = '/assets/'
var absolutePath = path.join(__dirname, 'build', assetPath)

module.exports = {
  devtool: 'cheap-module-eval-source-map',
  entry: [
    'webpack-hot-middleware/client',
    './src/index'
  ],

  target: 'node-webkit',

  output: {
    path: absolutePath,
    filename: 'bundle.js',
    publicPath: assetPath
  },
  plugins: [
    new webpack.optimize.OccurenceOrderPlugin(),
    new webpack.HotModuleReplacementPlugin(),
    new webpack.NoErrorsPlugin(),
    new ExtractTextPlugin("bundle.css")
  ],
  module: {
    loaders: [
      {
        test: /\.js$/,
        loaders: [ 'babel' ],
        exclude: /node_modules/,
        include: path.join(__dirname, 'src')
      },
      // fonts and svg
      { test: /\.woff(\?v=\d+\.\d+\.\d+)?$/, loader: "url?limit=10000&mimetype=application/font-woff" },
      { test: /\.woff2(\?v=\d+\.\d+\.\d+)?$/, loader: "url?limit=10000&mimetype=application/font-woff" },
      { test: /\.ttf(\?v=\d+\.\d+\.\d+)?$/, loader: "url?limit=10000&mimetype=application/octet-stream" },
      { test: /\.eot(\?v=\d+\.\d+\.\d+)?$/, loader: "file" },
      { test: /\.svg(\?v=\d+\.\d+\.\d+)?$/, loader: "url?limit=10000&mimetype=image/svg+xml" },
      {
        // images
        test: /\.(ico|jpe?g|png|gif)$/,
        loader: "file"
      },
      {
        // for some modules like foundation
        test: /\.scss$/,
        exclude: [/node_modules/], // sassLoader will include node_modules explicitly
        loader: ExtractTextPlugin.extract("style", "css!postcss!sass?outputStyle=expanded")
      },
      {
        test: /\.css$/,
        loader: ExtractTextPlugin.extract("style", "css!postcss")
      },

      { test: /\.json$/, loader: 'json-loader' },
      {
                test: /\.node$/,
                loader: 'node-loader'
      }


    ]
  },
  resolve: {
      extensions: [ '', '.js', '.json', '.jsx', '.es6', '.babel', '.node'],
      modulesDirectories: [ 'node_modules', 'app' ]
  },
  node: {
    console: true,
    fs: 'empty',
    net: 'empty',
    tls: 'empty'
  },
  postcss: function(webpack) {
    return [
      autoprefixer({browsers: ['last 2 versions', 'ie >= 9', 'and_chr >= 2.3']})
    ]
  },
  sassLoader: {
    includePaths: [path.resolve(__dirname, "node_modules")]
  }
}

package.json

{
  "name": "nodeReactMongo",
  "version": "1.0.0",
  "description": "redux-react-router and foundation boilerplate",
  "keywords": [
    "redux",
    "react",
    "router",
    "routing",
    "frontend",
    "client",
    "webpack",
    "babel",
    "sass",
    "foundation",
    "postcss"
  ],
  "main": "index.js",
  "scripts": {
    "start": "node server"
  },
  "author": "nitte93",
  "license": "ISC",
  "dependencies": {
    "axios": "^0.11.1",
    "classnames": "^2.2.0",
    "firebase": "^3.0.3",
    "font-awesome": "^4.3.0",
    "foundation-sites": "^6.1.2",
    "json-loader": "^0.5.4",
    "mongodb": "^2.1.20",
    "mongoose": "^4.4.19",
    "react": "^0.14.5",
    "react-addons-update": "^0.14.7",
    "react-dom": "^0.14.7",
    "react-modal": "^1.3.0",
    "react-router": "2.0.0-rc5",
    "react-router-redux": "^2.1.0",
    "redux": "^3.2.1",
    "redux-form": "^5.2.5",
    "redux-logger": "^2.5.2",
    "redux-thunk": "^1.0.3",
    "rethinkdb": "^2.3.1",
    "underscore": "^1.8.3",
    "what-input": "^1.1.4"
  },
  "optionalDependencies": {},
  "devDependencies": {
    "autoprefixer": "^6.3.2",
    "babel-core": "^6.3.15",
    "babel-loader": "^6.2.0",
    "babel-plugin-transform-runtime": "^6.5.0",
    "babel-preset-es2015": "^6.3.13",
    "babel-preset-react": "^6.3.13",
    "babel-preset-react-hmre": "^1.0.1",
    "babel-preset-stage-0": "^6.5.0",
    "babel-runtime": "^6.9.0",
    "css-loader": "^0.23.1",
    "express": "^4.13.3",
    "extract-text-webpack-plugin": "^1.0.1",
    "file-loader": "^0.8.5",
    "jquery": "^2.2.4",
    "node-sass": "^3.4.2",
    "postcss-loader": "^0.8.0",
    "react-redux": "^4.4.5",
    "redux-devtools": "^3.1.0",
    "redux-devtools-dock-monitor": "^1.0.1",
    "redux-devtools-log-monitor": "^1.0.3",
    "sass-loader": "^3.1.2",
    "script-loader": "^0.6.1",
    "serve-static": "^1.10.2",
    "style-loader": "^0.13.0",
    "url-loader": "^0.5.7",
    "webpack": "^1.9.11",
    "webpack-dev-middleware": "^1.2.0",
    "webpack-hot-middleware": "^2.2.0"
  }
}

在我执行 import mongoose from 'mongoose' 后立即在我的一个 react 组件文件中。我收到了这个错误。

import React, { Component, PropTypes } from 'react'
import request from '../api/requestHandler'
import { reduxForm } from 'redux-form'

//import rethink from 'rethinkdb'

import mongoose from 'mongoose'

Answer 1

当 Webpack 捆绑您的模块时，它会遵循您已导入(或需要)的模块的依赖链，并拉入其所有依赖项，并将它们一直捆绑到链的末尾。

如果有一个文件不知道如何在该依赖链中加载，则会抛出这种类型的错误。

这有时可以通过添加一个知道如何加载此类依赖项的加载程序来解决。但是，如果依赖项是非本地模块，则 Webpack 无法加载它。一些加载器知道如何通过 stub 和排除非本地部分来加载具有非本地依赖项的模块，以便加载。例如，在 fs 模块中，您不需要能够从磁盘读取和写入文件，因为浏览器无法做到这一点，因此无需包含该部分。

这就提出了一个问题:浏览器中需要 mongoose 模块的哪些功能？你能只包含那个功能而不是整个 mongoose 模块吗？

如果你能做到这一点，那么你可能能够解决 2 个问题:

1. 您可能会解决 Webpack 捆绑问题，因为您在项目中包含的 mongoose 部分没有有问题的子依赖项。
2. 您将使用 Webpack 创建一个更小的包，因为您将只包含您需要的部分，因此客户端的 bundle.js 有效负载会小得多。

例如，我最近需要在客户端使用 mongodb ObjectId 生成器。我发现 Webpack 无法处理 import mongodb from 'mongodb' 组件，因此深入研究了依赖项，我发现 mongodb 依赖于 mongodb-core 依赖于 bson ，它具有我需要的 ObjectId 方法。

通过仅导入该依赖链的 bson 组件，我解决了 Webpack 问题并使我的包更小。

如果您使用的是 Npm 3，那么如果您已经在使用 mongoose 或 mongodb，那么 bson 很有可能安装在 node_modules 的根目录中，这样您就可以import 而不在 package.json 中明确引用它。这显然会带来风险，如果上层依赖项停止依赖它，那么您的构建将中断，您需要独立 npm install 它。使用这种方法的优点是您将始终使用与上层依赖项使用的相同版本的 bson，这可能很重要。