Javascript Regex to replace not working as expected

Question

Test string is:

hello hello hello

<span class="self-reference">Tom</span> I don't know <span class="self-reference">Tom</span> I don't think.

I wish to to come out as:

hello hello hello

@Tom I don't know @Tom I don't think.

I use this regex:

comment = comment.replace(/\<span class="self-reference"\>(.*)\<\/span\>/gi,"@$1");

But it outputs:

hello hello hello

@Tom</span> I don't know <span class="self-reference">Tom I don't think.

Can anyone tell me how to modify this so it works as expected?

Obligatory.. stackoverflow.com/questions/1732348/…

James Montagne
– James Montagne

2012-09-12 13:59:47 +00:00
Commented Sep 12, 2012 at 13:59 — James Montagne
– James Montagne, Commented Sep 12, 2012 at 13:59

Community · Accepted Answer · 2020-06-20 09:12:55Z

3

Use non-greedy regex matching:

comment = comment.replace(/\<span class="self-reference"\>(.*?)\<\/span\>/gi,"@$1");

Without the ? I added, your regex (.*) will match the whole string up to the last </span> it founds in your string. Using non-greedy operator *? you make the match stop as soon as a match is found.

Lazy quantification

The standard quantifiers in regular expressions are greedy, meaning they match as much as they can.

(source)

edited Jun 20, 2020 at 9:12

CommunityBot

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answered Sep 12, 2012 at 14:00

sergio

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1 Comment

João Silva Over a year ago

Although it's the exact opposite of greedy :-)

dan-lee · Accepted Answer · 2012-09-12 14:02:41Z

2

Another possible solution:

comment = comment.replace(/\<span class="self-reference"\>([^<]+)\<\/span\>/gi,"@$1");

([^<]+) captures all chars until < is found

answered Sep 12, 2012 at 14:02

dan-lee

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