remove all but a specific portion of a string in javascript

Question

I am writing a little app for Sharepoint. I am trying to extract some text from the middle of a field that is returned:

var ows_MetaInfo="1;#Subject:SW|NameOfADocument
vti_parservers:SR|23.0.0.6421
ContentTypeID:SW|0x0101001DB26Cf25E4F31488B7333256A77D2CA
vti_cachedtitle:SR|NameOfADocument
vti_title:SR|ATitleOfADocument
_Author:SW:|TheNameOfOurCompany
_Category:SW|
ContentType:SW|Document
vti_author::SR|mrwienerdog
_Comments:SW|This is very much the string I need extracted
vti_categories:VW|
vtiapprovallevel:SR|
vti_modifiedby:SR|mrwienerdog
vti_assignedto:SR|
Keywords:SW|Project Name
ContentType _Comments"

So......All I want returned is "This is very much the string I need extracted"

Do I need a regex and a string replace? How would you write the regex?

Can you post the actual value of ows_MetaInfo? Your ...... and formatting make it difficult to test a solution. — James Hill
– James Hill, Commented May 1, 2012 at 19:20
Sure, and I will keep the formatting exactly as it is returned by Sharepoint... Thanks! — mrwienerdog
– mrwienerdog, Commented May 1, 2012 at 19:21

Jason Clark · Accepted Answer · 2012-05-01 19:38:14Z

2

Yes, you can use a regular expression for this (this is the sort of thing they are good for). Assuming you always want the string after the pipe (|) on the line starting with "_Comments:SW|", here's how you can extract it:

var matchresult = ows_MetaInfo.match(/^_Comments:SW\|(.*)$/m);
var comment = (matchresult==null) ? "" : matchresult[1];

Note that the .match() method of the String object returns an array. The first (index 0) element will be the entire match (here, we the entire match is the whole line, as we anchored it with ^ and $; note that adding the "m" after the regex makes this a multiline regex, allowing us to match the start and end of any line within the multi-line input), and the rest of the array are the submatches that we capture using parenthesis. Above we've captured the part of the line that you want, so that will present in the second item in the array (index 1).

If there is no match ("_Comments:SW|" doesnt appear in ows_MetaInfo), then .match() will return null, which is why we test it before pulling out the comment.

If you need to adjust the regex for other scenarios, have a look at the Regex docs on Mozilla Dev Network: https://developer.mozilla.org/en/JavaScript/Guide/Regular_Expressions

edited May 1, 2012 at 19:38

answered May 1, 2012 at 19:28

Jason Clark

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5 Comments

James Hill Over a year ago

I can't get this to work (jsfiddle.net/JamesHill/xCnap), but it must work because it's the accepted answer. Can you provide a working jsFiddle?

mrwienerdog Over a year ago

Worked for me great, only thing is that it is in Sharepoint, so I had to throw it into var matchresult = $(this).attr('ows_MetaInfo').match etc.... Because it's a CAML/SOAP/Sharepoint beast. Thanks a lot!

James Hill Over a year ago

@mrwienerdog, I don't doubt that it works, I just can't figure out why I can't get it working :)

Jason Clark Over a year ago

@JamesHill Two things: Your fiddle was missing the newlines that the original input should have had, and my original code was missing some semicolons (!). Here's a working fiddle: jsfiddle.net/jclark/9YMhn

James Hill Over a year ago

@JasonClark, beautiful! Thanks for the fiddle (I'm here to learn as well :D)!

anubhava · Accepted Answer · 2012-05-01 19:26:09Z

1

You can use this code:

var match = ows_MetaInfo.match(/_Comments:SW\|([^\n]+)/);
if (match)
   document.writeln(match[1]);

answered May 1, 2012 at 19:26

anubhava

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2 Comments

mrwienerdog Over a year ago

Thanks anubhava..... I know you were a minute before Jason Clark, but he gave me a cool bit of info, plus you have over 20K points to his scant few.... Share the wealth!

anubhava Over a year ago

You're welcome and I absolutely agree with your choice of accepted answer. I have myself upvoted @jasonclark

James Hill · Accepted Answer · 2012-05-01 19:27:11Z

1

I'm far from competent with RegEx, so here is my RegEx-less solution. See comments for further detail.

var extractedText = ExtractText(ows_MetaInfo);

function ExtractText(arg) {
    // Use the pipe delimiter to turn the string into an array
    var aryValues = ows_MetaInfo.split("|");

    // Find the portion of the array that contains "vti_categories:VW"
    for (var i = 0; i < aryValues.length; i++) {
        if (aryValues[i].search("vti_categories:VW") != -1)
            return aryValues[i].replace("vti_categories:VW", "");
    }

    return null;
}

Here's a working fiddle to demonstrate.

answered May 1, 2012 at 19:27

James Hill

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3 Comments

mrwienerdog Over a year ago

Thanks James, that is much more in line with how I would do it, as I am no master of regex either. However, because of the nature of the beast, regex was more prudent...

James Hill Over a year ago

@mrwienerdog, It's only more prudent if you never need to change it (or you're willing to wait for someone on SO to tell you how to change it). I always try to use what I'm comfortable with and capable of modifying if necessary. But, to each his own :)

mrwienerdog Over a year ago

I just know that I need to get more comfortable with regexes!

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