Is there a way how to write a JavaScript regular expression that would recognize .ts file extension for this:

"file.ts" 

but would fail on this:

"file.vue.ts"

What I need is, if the file name ends with .vue.ts, it shouldn't be handled as a .ts file.

I've tried a lot of things with no success.

Update: It needs to be a regular expression, because that's what I'm passing to a parameter of a function.

Is there a way how to write a JavaScript regular expression that would recognize .ts file extension for this:

"file.ts" 

but would fail on this:

"file.vue.ts"

What I need is, if the file name ends with .vue.ts, it shouldn't be handled as a .ts file.

I've tried a lot of things with no success.

Update: It needs to be a regular expression, because that's what I'm passing to a parameter of a function.

• javascript
• regex

Share Improve this question Follow edited Mar 22, 2018 at 18:04 Tom Shane asked Mar 22, 2018 at 17:47 Tom ShaneTom Shane 70477 silver badges1818 bronze badges 8

• has it to be a regular expression? – Nina Scholz Commented Mar 22, 2018 at 17:48
• /(.*).ts$/ this should check that the last 3 chars are '.ts' – PRDeving Commented Mar 22, 2018 at 17:49
• Possible duplicate of Regex JavaScript image file extension – Scott Weaver Commented Mar 22, 2018 at 17:50
• Possible duplicate of Javascript regex for matching/extracting file extension – Aman B Commented Mar 22, 2018 at 17:50
• @NinaScholz Yes, I need it to be a regular expression. – Tom Shane Commented Mar 22, 2018 at 17:51

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4 Answers 4

Sorted by: Reset to default 3

Regex for that is ^[^.]+.ts$

var x=/^[^.]+.ts$/;
console.log(x.test("file.ts"));
console.log(x.test("file.vue.ts"));
console.log(x.test("file.vue.ts1"));

Explanation:-

^[^.]+.ts$

^        ---> start of line
[^.]+    ---> match anything which is not '.' (match atleast one character)
^[^.]+   ---> match character until first '.' encounter
.ts      ---> match '.ts'
$        ---> end of line
.ts$     ---> string end with '.ts'

You could look for a previous ing dot and if not return true.

console.log(["file.ts", "file.vue.ts"].map(s => /^[^.]+\.ts$/.test(s)));

This will work except for special characters. Will allow for uppercase letters, lowercase letters, numbers, underscores, and dashes:

^[a-zA-Z0-9\_\-]+(\.ts)$

const regex = /(.*[^.vue]).ts/g;
abc.ts.ts Matches
abc.xyx.htm.ts Matches
abc.vue.ts Fails
xyz.abx.sxc.vue.ts Fails

Javascript regex should be this one.