Node.js file stats

Every file comes with a set of details that we can inspect using Node.js. In particular, using the stat() method provided by the fs module.

You call it passing a file path, and once Node.js gets the file details it will call the callback function you pass, with 2 parameters: an error message, and the file stats:

import fs from 'node:fs'
fs.stat('/Users/joe/test.txt', (err, stats) => {
  if (err) {
    console.error(err)
  }
  // we have access to the file stats in `stats`
})

Node.js also provides a sync method, which blocks the thread until the file stats are ready:

import fs from 'node:fs'
try {
  const stats = fs.statSync('/Users/joe/test.txt')
} catch (err) {
  console.error(err)
}

The file information is included in the stats variable. What kind of information can we extract using the stats?

A lot, including:

if the file is a directory or a file, using stats.isFile() and stats.isDirectory()
if the file is a symbolic link using stats.isSymbolicLink()
the file size in bytes using stats.size.

There are other advanced methods, but the bulk of what you'll use in your day-to-day programming is this.

import fs from 'node:fs'
fs.stat('/Users/joe/test.txt', (err, stats) => {
  if (err) {
    console.error(err)
    return
  }
  stats.isFile() // true
  stats.isDirectory() // false
  stats.isSymbolicLink() // false
  stats.size // 1024000 //= 1MB
})

You can also use promise-based fsPromises.stat() method offered by the fs/promises module if you like:

import fs from 'node:fs/promises'
try {
  const stats = await fs.stat('/Users/joe/test.txt')
  stats.isFile() // true
  stats.isDirectory() // false
  stats.isSymbolicLink() // false
  stats.size // 1024000 //= 1MB
} catch (err) {
  console.log(err)
}

You can read more about the fs module in the file system module documentation.

Node.js file stats ​

Node.js file stats