Every file comes with a set of details that we can inspect using Node.

In particular, using the stat() method provided by the fs module.

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

const fs = require('fs')
fs.stat('/Users/flavio/test.txt', (err, stats) => {
  if (err) {
    console.error(err)
    return
  }
  //we have access to the file stats in `stats`
})

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

const fs = require('fs')
try {
  const stats = fs.stat('/Users/flavio/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.

const fs = require('fs')
fs.stat('/Users/flavio/test.txt', (err, stats) => {
  if (err) {
    console.error(err)
    return
  }

  stats.isFile() //true
  stats.isDirectory() //false
  stats.isSymbolicLink() //false
  stats.size //1024000 //= 1MB
})