Nodejs get file extension

Question

I have a folder with images and they can have different formats but the name will always be unique. Is there a way to get the file extension if I know the file's name without the extension (eg. index and not index.html)? I could just check if the file exists for every extension I expect to be there but that seems like a bad solution to me.

Example: I know there is an image called PIC but I don't know the extension (could be either '.png', '.jpg' etc.) therefore I can not use the file command.

I want to remove the flag but unfortunately can't. If a mod could reject that would be great — user2630808
– user2630808, Commented May 6, 2016 at 15:07

Tom · Accepted Answer · 2016-05-06 14:55:50Z

2

Well, if your running Unix based systems, this could be a workaround.

var sys = require('util')
var exec = require('child_process').exec;

function puts(error, stdout, stderr) { 
   console.log(stdout) 
}

// this is where you should get your path/filename
var filename = "login";
// execute unix command 'file'
exec("file " + filename, puts);

I tested it for a PNG file and an EJS file, both with no extensions (what wouldn't make difference). The results are below:

PNG: photo: PNG image data, 100 x 100, 8-bit/color RGB, non-interlaced

EJS (what's basically a HTML): login: HTML document, ASCII text

You can check file command line parameters to make it easier to work with the string (e.g. file -b filename). If using Windows, then you'd have to check an alternative command for file.

Hope it's somehow useful.

answered May 6, 2016 at 14:55

Tom

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3 Comments

igor treptau Over a year ago

Thank you for your answer. I think I did not ask my question specific enough, so I updated my question.

Tom Over a year ago

Can you use the command dir or ls? I mean, if you can work with operation system comands, the code snipped in the answer could be adapted to the OS command (e.g. ls index* OR dir index*).

Can Rau Over a year ago

add -b and --extension to get a list of possible extensions..tested on jpg without extension gave me jpeg/jpg/jpe/jfif

Community · Accepted Answer · 2017-05-23 11:54:00Z

0

var path = require('path')

path.extname('index.html') // returns '.html'

Here is the referenced answer

Node.js get file extension

Updated :

https://www.npmjs.com/package/file-extension npm install --save file-extension allows you to specify a filename then it will return the extension

edited May 23, 2017 at 11:54

CommunityBot

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answered May 6, 2016 at 15:25

Jamesed

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2 Comments

igor treptau Over a year ago

As stated in my question I do not know the file's extension. I just know there is a file called 'index.SOMETHING'.

Jamesed Over a year ago

$ npm install --save file-extension here is the documentation npmjs.com/package/file-extension

blexshelwy · Accepted Answer · 2017-03-14 04:54:26Z

0

I know I'm late to the party, but you can use the grep command in unix based systems.

ie ls | grep PIC. What this does is first give a directory listing of the working directory, and then searches for the phrase PIC from the output of the directory listing and prints it. (so the only thing that will be printed is the filename)

In Windows, use dir PIC.* /b

You can execute these commands using child_process as shown in other answers

answered Mar 14, 2017 at 4:54

blexshelwy

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