javascript unterminated character class [duplicate]

Question

var badCode = "\(INST1,\\[0,";
var regex = new RegExp(badCode, "igm");

gets "unterminated character class" error.

How to fix?

TIA

trying suggestions from responders to this post, please see the following screen prints (you might have to right-click on images and open in new tab to make legible): note values of new_bad_thing (equiv of badCode above)

and here is the screen print when I hit the run button (please note the error message):

enter image description here

I get SyntaxError: Invalid regular expression: /(INST1,\[0,/: Unterminated group, i.e. the parenthesis (char 1 in string) doesn't have a matching ). It is being treated as a group as "\(" === "(", you need to write "\\(" to get \(. — Paul S.
– Paul S., Commented Feb 1, 2013 at 4:21

Ofer Zelig · Accepted Answer · 2013-02-01 03:46:10Z

12

Put another backslash at badCode:

var badCode = "\\(INST1,\\[0,";
var regex = new RegExp(badCode, "igm");

since you need one to escape ( inside the regex itself (signal it that it's a literal parentheis) and one escape for javascript.

edited Feb 1, 2013 at 3:46

answered Feb 1, 2013 at 3:45

Ofer Zelig

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4 Comments

davej Over a year ago

Tried that, badCode = "\\(INST1,\\[0,", still getting "unterminated character class". Verified that badCode is what you showed in chrome debugger.

Ofer Zelig Over a year ago

That's odd. See this fiddle which demonstrates it works.

davej Over a year ago

you're right. And yet, as you see from my screen shots, that's what I'm getting. Could it be a bug in chrome?

davej Over a year ago

Found the problem: even tho the debugger shows the "new_bad_thing" string as being the same as your "badcode", the chaining of the ".replace(/\\/g,"\\\\")" is causing the problem. When I take it out, the code works.

Ry- · Accepted Answer · 2013-02-01 03:44:34Z

3

No, it gets "unterminated parenthetical", because you've forgotten to escape the backslash. Why not use a regular expression literal?

var regex = /\(INST1,\[0,/igm;

answered Feb 1, 2013 at 3:44

Ry-♦

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6 Comments

davej Over a year ago

because badCode can be any number of things, I'm just using a literal as an example

Ry- Over a year ago

@davej: Then escape the first backslash with another backslash. But the error can't be "unterminated character class" with that string. Something is awry.

davej Over a year ago

thanks for your input, I edited the original post to show what I'm getting.

Ry- Over a year ago

@davej: It seems like the replacements should be \\) and \\(, not \\\\) and \\\\(.

davej Over a year ago

that's what I had originally, but I changed it match ofer zelig's solution

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