Node cannot find module "fs" when using webpack - node.js

Question

I'm using node.js and webpack to create a bundle. From what I've read, node.js should contain fs module for managing files. However when I call require("fs") I get an Cannot find module "fs" error. What should I do?

Answer 1

I came across this problem myself when bundling with webpack and found the answer on this thread.
The way to solve it for me was to use the following config:
module.exports = {
entry: "./app",
output: {
path: __dirname,
filename: "bundle.js"
},
module: {
loaders: [
{
test: /\.js$/,
exclude: 'node_modules',
loader: 'babel',
query: {presets: ['es2015']},
}
]
},
target: 'node'
};
By setting target to node webpack will make the necessary changes to bundle your node application
Edit: This answer targeted webpack 1.x which has now been superseded.

Answer 2

If you are running your webpack bundle in nodejs environment then target: 'node' is required in webpack.config.js file otherwise webpack takes default value as web for target check here.
You can resolve the issue in two ways
Add below configuration to your webpack.config.js
node: {
fs: "empty"
}
OR
Add below configuration to your package.json
"browser": {
"fs": false
}
Edit:
promising fix is
"browser": {
"fs": false
}

Answer 3

I had the same issue when bundling a NWjs application using webworkers (which in turn had node enabled).
The solution I found was to include each native module I used in externals with the prefix commonjs to the name of the module. For example:
...
target: "webworker", // or 'node' or 'node-webkit'
externals:{
fs: "commonjs fs",
path: "commonjs path"
}
...
I've done the same for targets "webworker" and "node-webkit" in different projects to solve the same issue.
webpack nwjs webworker nodejs node

Answer 4

Add below configuration to your webpack.config.js
resolve: {
fallback: {
fs: false
}
}

Answer 5

I needed to build a class that would use fetch if executed in a browser, or fs if executed in node. For other reasons, it was impractical to produce separate bundles, so I produced a single browser-targeted bundle.
The solution I used was to use eval('require("fs")') if the script was running in node.
const fs = eval('require("fs")')
Browser-safe (fs is null in the browser):
const fs = typeof window === 'object'
? null
: eval('require("fs")')

Answer 6

After trying everything I found on the internet (target, externals, node configs), the only solution that actually worked for me was replacing:
const filesystem = require("fs")
or
import fs from "fs"
by the special webpack version
const fs = __non_webpack_require__("fs")
This generates a require function that is not parsed by webpack.

Answer 7

In addition to the answer of PDG
I'm used to this short copy/paste candy.
Using path and fs :
var nodeModules = {};
fs.readdirSync(path.resolve(__dirname, 'node_modules'))
.filter(x => ['.bin'].indexOf(x) === -1)
.forEach(mod => { nodeModules[mod] = `commonjs ${mod}`; });
// Before your webpack configuration
module.exports = {
...
}
Then inside your configuration file, include the nodeModules variable in the externals
...
externals: nodeModules,
...

Answer 8

It would be more elegant to use pre-defined solution as:
Adding target: 'node' to webpack config file.
More info on: official documentation

Answer 9

For the solution we are building we had to force an older version of webpack:
npm install --save --force webpack#webpack-3