How to resolve fs.existsSync is not a function

Question

In NodeJS I have:

const fs = require('fs');
if (!fs.existsSync("some_path")) {
...
}

But I get the error:

TypeError: fs.existsSync is not a function

After doing some searching, I read that Webpack brings its own require which clobbers node.js's require, so when you require a node.js core module that webpack can't resolve to one of your files or dependencies, it throws.

(My stack trace includes __webpack_require__)

But how can I fix it?

Are you writing code intended to run in the browser? If so, how do you expect it to look through the file system? — Mark, Dec 18 '18 at 21:34

Krunal Rajkotiya · Answer 1 · 2021-06-14T10:20:52.813

27

I was facing the same Error like TypeError: fs.existsSync is not a function

So, I figured out that one extra line was added automatically which was creating this issue in import.

after removing this line from import

import { TRUE } from "node-sass";

the issue has been resolved.

edited Jun 14 '21 at 10:20

answered Oct 27 '20 at 07:44

Krunal Rajkotiya

1,070
9
14

3

This helped me, thanks! My editor (Visual Studio Code) somehow magically inserted `import { render } from 'node-sass';` at the top of my file. -.- – Page not found Nov 20 '20 at 02:07

score 7 · Answer 2 · answered Aug 09 '20 at 15:19

7

I had the same error that you have. Your vscode might have added a new module to your js file. Remove that module and your app should work just fine.

answered Aug 09 '20 at 15:19

KDSG

145
1
6

Mark · Accepted Answer · 2018-12-18T21:41:28.113

4

You can allow webpack to use the Node's require and include fs etc. by targeting node in the config:

module.exports = {
  entry: './src/main.js',
  target: 'node',
  output: {
    path: path.join(__dirname, 'build'),
    filename: 'backend.js'
  }
}

As described here: https://webpack.js.org/concepts/targets/ and https://webpack.js.org/configuration/target/

edited Dec 18 '18 at 21:41

answered Dec 18 '18 at 21:40

Mark

90,562
7
108
148

This is your webpack config file: https://webpack.js.org/configuration/ (add `webpack.config.js` in the root folder). – Mark Dec 18 '18 at 21:42
I'm using a template created using `create-react-app` (i think) so right now i have 3 `webpack.config.js` files: `...node_modules/react-scripts/config/webpack.config.dev.js` `...node_modules/react-scripts/config/webpack.config.prod.js` `...node_modules/raphael/webpack.config.dev.js` Do i need to use one of them or create a new one? – Gambit2007 Dec 18 '18 at 21:46
@Gambit2007 Not sure about configuring `react`, sorry. – Mark Dec 18 '18 at 21:49

score 4 · Answer 4 · answered Nov 19 '21 at 20:14

4

I was working on an electron application, I wanted to send a message from node and get in on the react side, but I was having that same issue when requiring ipcRenderer from electron, I tried import { ipcRenderer } from 'electron'; and const { ipceRenderer } = require('electron') This leads to an error due to webpack transforming node's require to its own webpack_require. See more info here

What worked for me was to use

const {ipcRenderer} = window.require('electron'); on the react side/renderer side from electron

answered Nov 19 '21 at 20:14

Jhon Arias

41
3

['TypeError: fs.existsSync is not a function' ReactJS and Electron](https://stackoverflow.com/questions/59477396/typeerror-fs-existssync-is-not-a-function-reactjs-and-electron) is probably a better thread for Electron problems. – ggorlen Apr 21 '22 at 15:46
get error: `Server Error ReferenceError: window is not defined` when use `window.require` – qg_java_17137 Jul 04 '23 at 01:14

ggorlen · Answer 5 · 2022-04-21T16:04:26.343

In my case, I forgot that I'd only imported the promises API, const fs = require("fs").promises, which doesn't have exist or existsSync functions in Node 17.4.0.

To use exist or existsSync, make sure you've imported fs using the sync API (const fs = require("fs")).

_{Note: I'm adding this answer as a possible solution for future visitors to a canonical thread for the error, not OP who appears to have required fs correctly.}

score 1 · Answer 6 · answered Mar 14 '21 at 13:56

It is nothing to worry about, check your code for something like import { types } from "node-sass";, it would have mistakenly and automatically imported without you know. Remove that line, and everything should work perfectly.

Even if it is not type, it is something from node-sass in your node_modules file, and you can't edit that file. So look for and remove import { types } from "node-sass"

score 0 · Answer 7 · answered Jun 29 '22 at 06:03

0

In my case VSCode added a arbitrary import from electron. After removing it my application worked.

import { Menu } from 'electron';

answered Jun 29 '22 at 06:03

David

51
1
6

Syed Umair Ali · Answer 8 · 2022-11-09T16:34:12.543

-1

In my case, i needed to send a message from the node to react. I tried importing ipcRenderer from 'electron'; and const ipceRenderer = require('electron') This results in an error owing to webpack changing the node's require to its own webpack require. See more info here

edited Nov 09 '22 at 16:34

answered Nov 09 '22 at 16:33

Syed Umair Ali

1
1

As it’s currently written, your answer is unclear. Please [edit] to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers [in the help center](/help/how-to-answer). – Community Nov 13 '22 at 16:26

How to resolve fs.existsSync is not a function

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