Check & match filename extension

Question

Let's say I have a filename 'file1.txt' How to check if a filename has either of these extensions (jpg, txt, mp4)?

If I add 'txt' first then it returns 1 (true)

var test = 'file1.txt';
test.substring(test.lastIndexOf(".")+1) === "txt"|"jpg"|"mp4"

and if I add 'txt' in the last like this "jpg"|"mp4"|"txt" then it returns 0.

I want to simply check that if a filename has any extension or not.

Put your file name inside quotes.And if you want to use OR condition then you have to check individually. — Krishna Prashatt, Jun 28 '18 at 10:48

score 2 · Accepted Answer · answered Jun 28 '18 at 10:48

2

I would use test here with a regex pattern:

console.log(/\.(txt|jpg|mp4)$/.test('file1.txt'));

One coding advantage here to the regex approach is we can just list all extensions we want to match in an alteration. In your current attempt, we can't compare a string to an alternation with ===.

answered Jun 28 '18 at 10:48

Tim Biegeleisen

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why does (/\.(jpg|mp4|txt)$/.test(test1)) === false returns false? – Jaz Jun 28 '18 at 11:51
Because the expression evaluates to true? Not sure what you are asking. – Tim Biegeleisen Jun 28 '18 at 11:53
my apologize, i misunderstood it. – Jaz Jul 03 '18 at 08:59

Check & match filename extension

1 Answers1