Split string in JavaScript using a regular expression

Question

I'm trying to write a regex for use in javascript.

var script = "function onclick() {loadArea('areaog_og_group_og_consumedservice', '\x26roleOrd\x3d1');}";
var match = new RegExp("'[^']*(\\.[^']*)*'").exec(script);

I would like split to contain two elements:

match[0] == "'areaog_og_group_og_consumedservice'";

match[1] == "'\x26roleOrd\x3d1'";

This regex matches correctly when testing it at gskinner.com/RegExr/ but it does not work in my Javascript. This issue can be replicated by testing ir here http://www.regextester.com/.

I need the solution to work with Internet Explorer 6 and above.

Can any regex guru's help?

Can you describe the behavior you are experiencing? Does it match at all? or just match the wrong section? — kelloti
– kelloti, Commented Jan 29, 2011 at 2:25
I'm getting the first match but second one appeared to be empty. — Simon
– Simon, Commented Jan 29, 2011 at 13:15

Alan Moore · Accepted Answer · 2011-01-29 14:40:57Z

1

Judging by your regex, it looks like you're trying to match a single-quoted string that may contain escaped quotes. The correct form of that regex is:

'[^'\\]*(?:\\.[^'\\]*)*'

(If you don't need to allow for escaped quotes, /'[^']*'/ is all you need.) You also have to set the g flag if you want to get both strings. Here's the regex in its regex-literal form:

/'[^'\\]*(?:\\.[^'\\]*)*'/g

If you use the RegExp constructor instead of a regex literal, you have to double-escape the backslashes: once for the string literal and once for the regex. You also have to pass the flags (g, i, m) as a separate parameter:

var rgx = new RegExp("'[^'\\\\]*(?:\\\\.[^'\\\\]*)*'", "g");
while (result = rgx.exec(script))
    print(result[0]);

edited Jan 29, 2011 at 14:40

answered Jan 29, 2011 at 6:08

Alan Moore

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3 Comments

Simon Over a year ago

Thanks for your reply, I seem to get the first match but the second one is undefined, I tried this at regextester.com matches: 0: ('areaog_og_group_og_consumedservice') 1: (undefined)

Alan Moore Over a year ago

That 1: refers to the contents of the first capturing group; it came out as undefined because that part of the regex didn't participate in the match. As a matter of fact, there shouldn't even be a first capturing group; I meant to use a non-capturing group like I did in the other regexes. (I'll fix that.) If you want to match two or more strings, you have to call exec() repeatedly as I demonstrated.

Simon Over a year ago

Arh, ok, I didn't realise that you could call exec multiple times. Thanks for your help.

kelloti · Accepted Answer · 2011-01-29 16:53:55Z

0

The regex you're looking for is .*?('[^']*')\s*,\s*('[^']*'). The catch here is that, as usual, match[0] is the entire matched text (this is very normal) so it's not particularly useful to you. match[1] and match[2] are the two matches you're looking for.

var script = "function onclick() {loadArea('areaog_og_group_og_consumedservice', '\x26roleOrd\x3d1');}";
var parameters = /.*?('[^']*')\s*,\s*('[^']*')/.exec(script);
alert("you've done: loadArea("+parameters[1]+", "+parameters[2]+");");

The only issue I have with this is that it's somewhat inflexible. You might want to spend a little time to match function calls with 2 or 3 parameters?

EDIT In response to you're request, here is the regex to match 1,2,3,...,n parameters. If you notice, I used a non-capturing group (the (?: ) part) to find many instances of the comma followed by the second parameter.

/.*?('[^']*')(?:\s*,\s*('[^']*'))*/

edited Jan 29, 2011 at 16:53

answered Jan 29, 2011 at 2:59

kelloti

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1 Comment

Simon Over a year ago

Thanks for reply and the heads up on ignoring the first match. This meet's the questions requirement, thank you. I should of also specified that sometime there's only one parameter in the script. Are you able to tweek it to allow for that please?

kolko · Accepted Answer · 2011-01-28 20:44:32Z

0

Maybe this:

'([^']*)'\s*,\s*'([^']*)'

answered Jan 28, 2011 at 20:44

kolko

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1 Comment

Simon Over a year ago

Thanks for your reply, this works thank you. I should of also specified that sometime there's only one parameter in the script

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