Store regex in string in javascript?

Question

Possible Duplicate:
Converting user input string to regular expression
javascript new regexp from string

I am having a little bit of a problem with regex in javascript (I'm not too used to regex in javascript just yet). I wanna replace some stuff in a string and I noticed the syntax for writing regex seems to be without ' or " like this: var replacedtitle = title.replace(/\[.*?\]/g, "");

Now this all work as intended, but I want the user to be able to add his own regexes from the interface without changing the code (I'm doing a private project for a friend who doesn't code, and I want to be able to just send him the regexes to input when something new needs to be replaced instead of me repackaging everything every time). I did this by having a xul textbox (this is a firefox addon, but should be the same as if it was a html textbox) where he inputs the regexes, it gets added to a json object and saved. I tried doing something like this:

var replacedtitle = "";
for(a = 0; a < regex.data.length;a++){
    replacedtitle = title.replace(regex.data[a].regex, "");
}

but it wont work. I suspect it's because regex.data[a].regex would be taken as a string, yet replace() doesn't seem to take string as the first parameter, right?

I am a bit uncertain about this, any help would be much appreciated.

score 13 · Accepted Answer · edited Oct 03 '12 at 15:27

13

You can create a RegEx object with new instead, and provide the pattern and modifiers with strings;

var re = new RegExp("\\[.*?\\]", "g");

edited Oct 03 '12 at 15:27

raina77ow

103,633
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answered Oct 03 '12 at 15:20

Björn

29,019
9
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2

oh thank you. I tried this one but I didn't know you had to remove the `/` around the regex. It works properly now, tackar :> – galaxyAbstractor Oct 03 '12 at 15:24
2

@raina77ow -- Thank's for the edit, I was too quick there... – Björn Oct 03 '12 at 15:31

score 3 · Answer 2 · answered Oct 03 '12 at 16:06

Splitting string into pattern and modifiers.

function getRegFromString(string){

     var a = string.split("/");
     modifiers= a.pop(); a.shift();
     pattern = a.join("/");
     return new RegExp(pattern, modifiers);
}
getRegFromString("/\[.*?\]/gim");

score -1 · Answer 3 · answered Oct 03 '12 at 15:22

-1

var string = "/\[.*?\]/g";
var regex = new RegExp(string);

ll work normaly.

answered Oct 03 '12 at 15:22

PierrickP

107
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Store regex in string in javascript?

3 Answers3