CODEWITHSUNDEEP
node.jswebpack
Gambit2007
Gambit2007

Reputation: 3996

How to resolve fs.existsSync is not a function

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?

Upvotes: 29

Views: 81629

Answers (8)

Syed Umair Ali
Syed Umair Ali

Reputation: 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

Upvotes: -1

David
David

Reputation: 51

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

import { Menu } from 'electron';

Upvotes: 0

ggorlen
ggorlen

Reputation: 57175

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.

Upvotes: 2

Jhon Arias
Jhon Arias

Reputation: 41

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

Upvotes: 4

Krunal Rajkotiya
Krunal Rajkotiya

Reputation: 1130

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

enter image description here

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

enter image description here

after removing this line from import

import { TRUE } from "node-sass";

the issue has been resolved.

Upvotes: 28

Gtstrides
Gtstrides

Reputation: 435

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"

Upvotes: 1

KDSG
KDSG

Reputation: 165

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.

Upvotes: 8

Mark
Mark

Reputation: 92460

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/

Upvotes: 4

Related Questions