Webpack bundling doesn't include specific module such as 'sequelize' - node.js

Question

I'm developing nodejs with webpack, seqelize and other modules with below webpack configuration.
const path = require('path');
const webpack = require('webpack');
const fs = require('fs');
const glob = require('glob');
const CleanWebpackPlugin = require('clean-webpack-plugin');
var nodeModules = {};
fs.readdirSync('node_modules')
.filter(function(x) {
return ['.bin'].indexOf(x) === -1;
})
.forEach(function(mod) {
nodeModules[mod] = 'commonjs ' + mod;
});
module.exports = {
// entry: [ path.resolve(__dirname, 'server.js'), models ],
entry: glob.sync(path.resolve(__dirname, 'src/**/*.js')),
resolve: {
// Add `.ts` and `.tsx` as a resolvable extension.
root : [path.resolve(__dirname, '')],
extensions: ['', '.webpack.js', '.web.js', '.ts', '.tsx', '.js'],
modulesDirectories: ['node_modules']
},
module: {
loaders: [
{
test: /\.js$/,
loader: 'babel',
exclude: /node_modules/,
query: {
cacheDirectory: true,
presets: ['es2015']
}
}, {
test: /\.json$/,
loader: 'json'
}
]
},
plugins: [
new CleanWebpackPlugin(['build'], {
root: path.resolve(__dirname, ''),
verbose: true,
dry: false,
exclude: [],
watch: true
})
],
node: {
__filename: true,
__dirname: true
},
target: 'node',
externals: nodeModules,
output: {
path: path.resolve(__dirname, 'build'),
filename: 'server.[chunkhash].js',
libraryTarget: 'commonjs'
}
}
In this case, I try to bundle the whole sources with the config and then get the bundled file named server.[chunkhash].js.
I want to move the file to server and just make work with a command like node server.[chuckhash].js, however, I got the message like below.
module.js:472
throw err;
^
Error: Cannot find module 'sequelize'
at Function.Module._resolveFilename (module.js:470:15)
at Function.Module._load (module.js:418:25)
at Module.require (module.js:498:17)
at require (internal/module.js:20:19)
...
So, I tried to find the specific point to make the error, and then found out my models/index.js use the seqelize module for below codes.
import fs from 'fs';
import path from 'path';
import Sequelize from 'sequelize';
import config from 'config/env';
const sequalize = new Sequelize(config.mysql.database, config.mysql.username, config.mysql.password, config.mysql.params.options);
const db = {};
fs.readdirSync(__dirname)
.filter(file => {
return (file.indexOf('.') !== 0) && (file !== 'index.js');
})
.forEach(file => {
const model = sequalize.import(path.resolve(__dirname, file));
db[model.name] = model;
});
Object.keys(db).forEach(modelName => {
if ('associate' in db[modelName]) {
db[modelName].associate(db);
}
});
db.sequelize = sequalize;
db.Sequelize = Sequelize;
export default db;
How could I fix this issue?
Actually, with the nodemodule in the same folder, there has been no error, but, make the bundled file, it will make the error.

Answer 1

You defined all your node_modules as externals (externals: nodeModules,). This means that webpack won't bundle any module that comes from node_modules and will just leave the imports to be resolved at runtime, just like it would when running it in Node without using webpack. For this to work you need to have the modules available wherever you run the bundle.
If you want webpack to bundle the node_modules as well, you can remove the externals option.
The externals config you're using likely came (directly or indirectly) from Backend Apps with Webpack (Part I) and you should read that blog post to understand what it's really doing and whether you need it.