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

Question

I'm making a react app using Babel and Webpack and I want to use the file-exists package from npm. I already installed and saved the package as a dependency for my project. After running npm start I get this error:
ERROR in ./~/file-exists/index.js
Module not found: Error: Cannot resolve module 'fs' in C:\GitHub\CryptoPrices\node_modules\file-exists
# ./~/file-exists/index.js 3:9-22
file-exists uses fs as a dependency but for some reason it is not working. Npm starts and runs without any issues if I don't require file-exists anywhere.
here is my webpack config file:
module.exports = {
entry: [
'./src/index.js'
],
output: {
path: __dirname,
publicPath: '/',
filename: 'bundle.js'
},
module: {
loaders: [{
// exclude: /node_modules/,
loader: 'babel',
query: {
presets: ['react', 'es2015', 'stage-1']
}
}]
},
resolve: {
extensions: ['', '.js', '.jsx']
},
devServer: {
historyApiFallback: true,
contentBase: './'
}
};
I'm new to Webpack and Babel so I'm a little bit lost.

Answer 1

It looks like you're calling the fs file-exists method in your index.js file. I'm not sure in what context you're calling the method, but this looks like a client-side call to a server-side method. I ran into a similar issue just recently.
From what I understand, the main issue seems to be that you can't call server-side (Node) methods in browser-interpreted client-side (front end) code. You have to call them from a server.
Webpack can load the fs module code into your front end, but the browser can't actually interpret those Node methods and run them; only a Node environment can do that. (more here)
You could fix the core issue by modifying the call to fs methods to happen somewhere server-side, or by finding an equivalent browser-supported package that offers the same functionality as the fs methods you need but that can be run in a browser.
A quick search for "fs module for browser" brings up a variety of options that might work for what you need, like fs-web, browserify-fs or filer.
Here is a similar question with some insight.
Use fs module in React.js,node.js, webpack, babel,express

Answer 2

node: {
fs: 'empty'
}
try to add the code above to your webpack config file and the error should disappear.