The way to check if a file exists in the filesystem, using Node.js, is by using the fs.existsSync() method:

const fs = require('fs')

const path = './file.txt'

try {
  if (fs.existsSync(path)) {
    // file exists
  }
} catch (err) {
  console.error(err)
}

This method is synchronous and blocks the event loop. To check asynchronously, use fs.access(), which checks whether a file exists without opening it:

const fs = require('fs')

const path = './file.txt'

fs.access(path, fs.F_OK, (err) => {
  if (err) {
    console.error(err)
    return
  }

  // file exists
})

Lessons in this unit:

0:	Introduction
1:	▶︎ How to check if a file exists in Node.js
2:	How to create an empty file in Node.js
3:	How to get the names of all the files in a folder in Node
4:	How to get the last updated date of a file using Node.js
5:	How to remove a file with Node.js
6:	How to write a JSON object to file in Node.js
7:	How to empty a folder in Node.js
8:	Working with file descriptors in Node
9:	Node File Paths
10:	Node file stats
11:	Working with folders in Node
12:	How to use the Node.js fs module with async/await
13:	How to get the current folder in Node
14:	How to get the file extension in Node.js from the MIME type
15:	How to get the file extension in Node.js
16:	How to list files in a folder in Node
17:	How to mass rename files in Node.js
18:	Node.js get all files in a folder recursively
19:	Incrementing multiple folders numbers at once using Node.js
20:	Save some text to a file in Node.js