JavaScript Regex to find string that ends in ".js" but not "-min.js"

Question

As the title states: Can any one help me figure out how to write a JavaScript regex expression that matches a string that end in ".js" but fails when given a string that ends in "-min.js".

Examples:

hello.js -> match

hellomin.js -> match

hello-min.js -> no match

hello-min-hello.js -> match

Thanks!

robinCTS · Accepted Answer · 2013-01-28T16:24:13.867

3

Use negative lookahead:

(?!-min)[\w-]{4}\.js$

Update

This will also work for less than 4 characters before the .js:

(?:(?!-min)[\w-]{4}|^[\w-]{1,3})\.js$

edited Jan 28 '13 at 16:24

answered Jan 28 '13 at 14:11

robinCTS

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This looks like it works but will fail if there are less than four characters preceding ".js" – Sidawy Jan 28 '13 at 14:33
@Sidawy - Updated answer to fix this. – robinCTS Jan 28 '13 at 14:44

score 2 · Answer 2 · edited May 23 '17 at 11:58

2

Use the pseudo-inverted matching based on a previous question:

^((?!-min\.).)*\.js$

edited May 23 '17 at 11:58

Community

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answered Jan 28 '13 at 14:14

oleq

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score 0 · Answer 3 · answered Jan 28 '13 at 14:13

Since JS does not support negative lookbehind, lets use negative lookahead!

var str = 'asset/34534534/jquery.test-min.js',
    reversed = str.split('').reverse().join('');

// And now test it
/^sj\.(?!nim-)/.test(reversed); // will give you false if str has min.js at the end

Funny, right?

score 0 · Answer 4 · answered Feb 11 '15 at 07:01

I have extended @robinCTS's regex to match file paths with more than one dot (for example with version number at the end of filename) and also a string that ends in ".min.js":

(?:(?!(-|\.)min)[\w\.-]{4}|^[\w\.-]{1,3})\.js$

Examples:

hello.js -> match
hellomin.js -> match
hellomin-2.4.3.js -> match
hello-min-hello.js -> match
hello-min.js -> no match
hello.min.js -> no match
hellomin-2.4.3-min.js -> no match
hellomin-2.4.3.min.js -> no match

score -1 · Answer 5 · answered Jan 28 '13 at 14:00

-1

You can use negative lookbehind :

(?<!-min)\.js$

Example

answered Jan 28 '13 at 14:00

Pilou

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JS regex doesn't support negative lookbehind! ;) – oleq Jan 28 '13 at 14:02

JavaScript Regex to find string that ends in ".js" but not "-min.js"

5 Answers5