How can an string be replaced in JavaScript with regex

Question

How can a string be replaced in Javascript with regex ?

A particular regular expression is bugging me right now. I simply want to replace the count=15 in a string like:

countryNo=-1&count=15&page=2

How can I get a format like given below:

countryNo=-1&count=**20**&page=2

Or

countryNo=-1&count=**30**&page=2

I have tried the following:

var x = 'countryNo=-1&count=15&page=2';
x = x.replace('count=\d{2}', 'count=30');

Nothing happens. How can I make it work?

Florian Margaine · Accepted Answer · 2013-10-18 12:37:46Z

6

Use a regex literal, not a string literal:

x = x.replace(/count=\d{2}/, 'count=30');

Reference: MDN on regular expressions

As an aside, you could be DRYer, you don't have to repeat "count=":

x = x.replace(/(count=)\d{2}/, '$130');

edited Oct 18, 2013 at 12:37

Florian Margaine

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answered Oct 18, 2013 at 12:27

Denys Séguret

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3 Comments

Barrie Reader Over a year ago

For completness sake, could you explain DRYer (edit)cheers!

Denys Séguret Over a year ago

@Neurofluxation It means "more DRY", with DRY being an acronym for "Don't Repeat Yourself", which is an important principle for maintainable coding.

Barrie Reader Over a year ago

You know... Programming since I was 10 or 11 and never heard the acronym DRY. I've heard Don't Repeat Yourself a lot, but never DRY. Here, have an upvote!

Halcyon · Accepted Answer · 2013-10-18 12:27:41Z

0

You're specifying your regular expression as a string. Use:

x = x.replace(/count=\d{2}/, 'count=30');

answered Oct 18, 2013 at 12:27

Halcyon

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Comments

Hemant Metalia · Accepted Answer · 2013-10-18 12:28:10Z

0

Remove the Regex from the string literal

try following

x = x.replace(/count=\d{2}/, 'count=30');

answered Oct 18, 2013 at 12:28

Hemant Metalia

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