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To get a filename extension, you can use a combination of split() and pop() methods. The split() method will convert a string into an array of substrings, separated by the character you passed as the method's parameter. And that's how you can get the file extension from a filename.
If filename is empty or null, getExtension(String filename) will return the instance it was given. Otherwise, it returns extension of the filename. To do this it uses the method indexOfExtension(String) which, in turn, uses lastIndexof(char) to find the last occurrence of the '.
The full filename is first obtained by selecting the file input and getting its value property. This returns the filename as a string. By the help of split() method, we will split the filename into 2 parts. The first part will be the filename and the second part will be the extension of the file.
If you have file object from request then you can simply get by laravel function. $extension = $request->file->extension(); dd($extension); If you have file object from request then you can simply get by laravel function.
A variant that works with all of the following inputs:
"file.name.with.dots.txt""file.txt""file"""nullundefinedwould be:
var re = /(?:\.([^.]+))?$/;
var ext = re.exec("file.name.with.dots.txt")[1]; // "txt"
var ext = re.exec("file.txt")[1]; // "txt"
var ext = re.exec("file")[1]; // undefined
var ext = re.exec("")[1]; // undefined
var ext = re.exec(null)[1]; // undefined
var ext = re.exec(undefined)[1]; // undefined
Explanation
(?: # begin non-capturing group
\. # a dot
( # begin capturing group (captures the actual extension)
[^.]+ # anything except a dot, multiple times
) # end capturing group
)? # end non-capturing group, make it optional
$ # anchor to the end of the string
I personally prefer to split the string by . and just return the last array element :)
var fileExt = filename.split('.').pop();
If there is no . in filename you get the entire string back.
Examples:
'some_value' => 'some_value'
'.htaccess' => 'htaccess'
'../images/something.cool.jpg' => 'jpg'
'http://www.w3schools.com/jsref/jsref_pop.asp' => 'asp'
'http://stackoverflow.com/questions/680929' => 'com/questions/680929'
Use the lastIndexOf method to find the last period in the string, and get the part of the string after that:
var ext = fileName.substr(fileName.lastIndexOf('.') + 1);
I would recommend using lastIndexOf() as opposed to indexOf()
var myString = "this.is.my.file.txt"
alert(myString.substring(myString.lastIndexOf(".")+1))
Better to use the following; Works always!
var ext = fileName.split('.').pop();
This will return the extension without a dot prefix. You can add "." + ext to check against the extensions you wish to support!
var x = "1.txt";
alert (x.substring(x.indexOf(".")+1));
note 1: this will not work if the filename is of the form file.example.txt
note 2: this will fail if the filename is of the form file
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