{

How to get file metadata information in Nodejs app| fs stat example


how to get file metadata information such as size  from Nodejs Application

file contains content and type. Apart from this, you will have metadata of a file

It is very easy to get the file information in Operating systems such as windows.

How do you get file metadata information in Nodejs?

Nodejs provides inbuilt module - fs and it contains stat() and statSync() method to get metadata properties of an file or a directory.

It provides two methods

  • fs.statSync method
  • fs.start method

How to get file metadata such as size created date

There are two ways we can get it done.

nodejs fs stat method

stat() is an asynchronous operation for reading the file and printing the object of metadata.

fs.stat(path, options, callbackfunction)

path is a file or directory absolute or relative path options are optional parameters passed to customize the output, bigint is false or true. true means numeric values returned by this option callback is a function which contains first parameter error in case of errors, second parameter an object return file metadata object.

In Nodejs asynchronous operations contains a callback

const fs = require("fs")

fs.stat("./package.json", (err, fileObject) => {
    if (err) {
        console.log(err)
    } else {
        console.log(fileObject)
    }
})

Output:

Stats {
  dev: 3330445139,
  mode: 33206,
  nlink: 1,
  uid: 0,
  gid: 0,
  rdev: 0,
  blksize: 4096,
  ino: 562949955554406,
  size: 204,
  blocks: 0,
  atimeMs: 1645280252542.7854,
  mtimeMs: 1644120598975.729,
  ctimeMs: 1644120598975.729,
  birthtimeMs: 1642860250548.1833,
  atime: 2022-02-19T14:17:32.543Z,
  mtime: 2022-02-06T04:09:58.976Z,
  ctime: 2022-02-06T04:09:58.976Z,
  birthtime: 2022-02-22T14:04:10.548Z
}

Here are details of a returned object

dev: device identifier in numeric, mode: file type in bits, nlink:hard links count, uid: file owner identifier, gid: group identifier of an owner for a file rdev: special file identifier blksize: file system block size, ino: inode number for a file, size: file size in bytes, blocks: blocks allocated for a file, atimeMs: last accessed timestamp in milliseconds mtimeMs: file modified timestamp in milliseconds ctimeMs: file status changed timestamp in milliseconds birthtimeMs: created timestamp in milliseconds atime: last accessed Date format with timezone information mtime: file modified Date format with timezone information ctime: file changed Date format with timezone information, birthtime: file created Date format with timezone information

It provides the following methods.

const fs = require("fs")

fs.stat("./package.json", (err, fileObject) => {
    if (err) {
        console.log(err)
    } else {
        console.log(fileObject.isFile()) // return true for files
        console.log(fileObject.isDirectory())// true for directory
        console.log(fileObject.isBlockDevice())
        console.log(fileObject.isSymbolicLink()) return true for symbolic link
        console.log(fileObject.isCharacterDevice())
        console.log(fileObject.isFIFO())
        console.log(fileObject.isSocket())
    }
})

Output:

true
false
false
false
false
false
false

Nodejs fs statSync function

statSync is a synchronization version of the start function. It executes sequentially and waits for execution to finish before going to the next line.

Here is a syntax fs.statSync(path, options)

path is the absolute or relative path of a resource(file, directory) options contains javascript with bigint is key and value is true/false. if true, the output returns numbers in biginteger format.

const fileInfo = fs.statSync('./package.json')
console.log(fileInfo)

It

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