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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:

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

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

const fs = require('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.

const fs = require('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
})