Javascript Regex For Comma Delimited String

Question

I need a regex expression that performs a "contains" function on a input/type=hidden field's value. This hidden field stores unique values in a comma delimited string.

Here's a scenario.
The value: "mix" needs to be added to the hidden field. It will only be added if it does not exist as a comma delimited value.

With my limited knowlege of regex, I can't prevent the search from returning all ocurrences of the "mix" value. For example if: hiddenField.val = 'mixer, mixon, mixx', the regex always returns true, because the all three words contain the "mix" characters.

Thanks in advance for the help

Community · Accepted Answer · 2017-05-23 10:09:12Z

3

You can use \b metacharacter to set word boundaries:

var word = "mix";
new RegExp("\\b" + word + "\\b").test(hidden.value);

DEMO: http://jsfiddle.net/ztYff/

UPDATE. In order to protect our regular expression of possible problems when using variable instead of hardcoding (see comments below), we need to escape special characters in word variable. One possible solution is to use the following method:

RegExp.escape = function(text) {
    return text.replace(/[-[\]{}()*+?.,\\^$|#\s]/g, "\\$&");
}

DEMO: http://jsfiddle.net/ztYff/1/

UPDATE 2. Following @Porco's answer we can combine regular expressions and string splitting to get another universal solution:

hidden.value.split(/\s*,\s*/).indexOf(word) != -1;

DEMO: http://jsfiddle.net/ztYff/2/

edited May 23, 2017 at 10:09

CommunityBot

11 silver badge

answered Jun 1, 2012 at 22:41

VisioN

146k35 gold badges287 silver badges291 bronze badges

Sign up to request clarification or add additional context in comments.

7 Comments

Tomalak Over a year ago

This is not a good idea. You really should regex-quote the word to avoid run-time errors.

VisioN Over a year ago

@Tomalak Not really got what you mean. Could you give an example.

Tomalak Over a year ago

What if word contains a backslash? Or a dollar sign? This will break your solution. (Not in this special case, but generally when you build regex from strings.)

VisioN Over a year ago

@Tomalak Ah... well, it will break any universal solution like this. Of course, word should be secured. Let me think about the better way.

VisioN Over a year ago

@Tomalak Now regexp should be protected.

|

Porco · Accepted Answer · 2012-06-01 23:08:15Z

2

hiddenField.val.split(',').indexOf('mix') >= 0

Could also use a regex(startofstring OR comma + mix + endofstring OR comma):

hiddenField.val.match(/(,|^)mix($|,)/)

edited Jun 1, 2012 at 23:08

answered Jun 1, 2012 at 22:31

Porco

4,2033 gold badges25 silver badges25 bronze badges

4 Comments

Felix Kling Over a year ago

Array.prototype.indexOf is only supported in IE9 though.

Tomalak Over a year ago

the MDN has a backwards-compatible implementation of indexOf() for browsers that are missing it: developer.mozilla.org/en/JavaScript/Reference/Global_Objects/…

Porco Over a year ago

added regex for alternative method

RichardB Over a year ago

I like the simplicity of your answer. I'll need to do some performance tests to see if the two operations: split and indexOf will perform faster than a single regex expression.

Danilo Valente · Accepted Answer · 2012-06-01 22:32:53Z

0

hiddenField.val.match(/^(mix)[^,]*/);

answered Jun 1, 2012 at 22:32

Danilo Valente

11.4k8 gold badges55 silver badges71 bronze badges

Comments

Felix Kling · Accepted Answer · 2012-06-01 22:48:12Z

0

How about:

/(^|,)\s*mix\s*(,|$)/.test(field.value)

It matches mix, either if it is at the beginning of a string or at the end or in between commas. If each entry in the list can consist of multiple words, you might want to remove the \s*.

answered Jun 1, 2012 at 22:48

Felix Kling

820k181 gold badges1.1k silver badges1.2k bronze badges

Collectives™ on Stack Overflow

Javascript Regex For Comma Delimited String

4 Answers 4

7 Comments

4 Comments

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

4 Answers 4

7 Comments

4 Comments

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related