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):

Answer 1

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.