Split with regex including an alternative | incorrectly returns splitting tokens




JavaScript Engine
8 years ago
8 years ago


(Reporter: Guillaume Bodi, Unassigned)


Firefox Tracking Flags

(Not tracked)




8 years ago
User-Agent:       Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10_6_4; en-US) AppleWebKit/533.4 (KHTML, like Gecko) Chrome/5.0.375.126 Safari/533.4
Build Identifier: Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv: Gecko/20100722 Firefox/3.6.8

Splitting a string on a regular expression including a choice point (ex. /a|b/)  will return the splitting tokens as part of the result array.

Reproducible: Always

Steps to Reproduce:
1. Create a string ex.                                                            var string = "'test' and 'test2' or 'test3'";
2. Split it with a regex involving an alternative. ex.        string.split(/and|or/);
3. Check the return array.
Actual Results:  
 ["'test' ", "and", " 'test2' ", "or", " 'test3'"]

Expected Results:  
 ["'test' ", " 'test2' ", " 'test3'"]
I can't repro this with my 3.6.8 build [Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv: Gecko/20100723 Ubuntu/10.04 (lucid) Firefox/3.6.8] using URL:

javascript:var string = "'test' and 'test2' or 'test3'"; var result = string.split(/and|or/); document.write(result.toSource())

Can somebody with an OS X machine handy give it a shot?

Comment 2

8 years ago
Sorry, I incorrectly copied the regex: /(and|or)/ instead of /and|or/

Try with this URL instead
javascript:var string = "'test' and 'test2' or 'test3'"; var result = string.split(/(and|or)/); document.write(result.toSource())
(In reply to comment #2)
> Sorry, I incorrectly copied the regex: /(and|or)/ instead of /and|or/

We do this correctly per ECMAScriptv5 section

If separator is a regular expression that contains capturing parentheses, then each time separator is matched the results (including any undefined results) of the capturing parentheses are spliced into the output array.

For example,


evaluates to the array

["A", undefined, "B", "bold", "/", "B", "and", undefined,
"CODE", "coded", "/", "CODE", ""]

Thanks for reporting, though!
Last Resolved: 8 years ago
Resolution: --- → INVALID
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