regex match unique results

Question

I have the following situation, I'm searching in a HTML string the attributes.

I have the following regex wich works alright but I want to get just unique results, of course I can apply some filter to the results array but I think this is achieveable with pure regex.

https://regex101.com/r/UqCuJS/1

So in this situation class is returned twice, but I only want 1 time:

['class', 'data-text'] not ['class', 'data-text', 'class']

const html = `<div class="foo">
 <span data-text="Some string" class="bar"></span>
</div>`

console.log(html.match(/[\w-:]+(?=\s*=\s*".*?")/g))

http://jsbin.com/bekibanisa/edit?js,console

Can you include full `javascript` tried at Question? Are you using `.split()` or `.match()` to get array of matches? — guest271314, Apr 30 '17 at 15:15
http://jsbin.com/bekibanisa/edit?js,console check this out, .match — Anderson, Apr 30 '17 at 15:16
@WiktorStribiżew your answer seems right, can you post it with an explanation of what is happening? — Anderson, Apr 30 '17 at 15:21
Keep in mind that multi grouping (@WiktorStribiżew example) has big performance penalties. So I suggest you to use filter instead — Maxim Shoustin, Apr 30 '17 at 15:35
Yes, the greedy patterns with a construct matching any char, any number of times, will cause much backtracking. Use `/[\w-:]+(?=\s*=\s*"[^"]*")/g` and use `.filter()`. — Wiktor Stribiżew, Apr 30 '17 at 15:49

score 10 · Accepted Answer · answered Apr 30 '17 at 15:47

10

You can pass result of .match() to Set, which does not allow duplicate values. If necessary convert Set instance back to Array.

const html = `<div class="foo">
 <span data-text="Some string" class="bar"></span>
</div>`
// or use existing `RegExp`
console.log([...new Set(html.match(/([\w-]+)(?=[=]")/g))])

answered Apr 30 '17 at 15:47

guest271314

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this is awesome – Anderson Apr 30 '17 at 17:03

score -1 · Answer 2 · answered Apr 30 '17 at 15:19

-1

Try removing the '/g' global modifier

console.log(html.match(/[\w-:]+(?=\s*=\s*".*?")/))

answered Apr 30 '17 at 15:19

Jed

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then dosent match data-text, just first attribute, its not correct! – Anderson Apr 30 '17 at 15:20
It'll only return the first match not the complete one. – Syed Kashan Ali Oct 08 '22 at 11:44

regex match unique results

2 Answers2