Fix JSLint bad escapement warning in RegEx
I have the following code in a 3rd party jQuery control called jquery.facebox.js that JSLint doesn't like. It's a bad escapement error in a RegEx.
Regular expression are like Romulan to me, so I can't see how to fix the error (which is with the period character in the RegEx):
var i开发者_如何转开发mageTypes = $.facebox.settings.imageTypes.join('|');
$.facebox.settings.imageTypesRegexp = new RegExp('\.(' + imageTypes + ')$', 'i');
Add a second \
after '\
. This is a string problem, not a regex problem :-)
To have a \
in a string in Javascript (and many other languages) you need to escape it, because it is used for escape sequences (like \n
). So to have a \
you have to put \\
.
In regexes \
is used to escape the next character, but that is another escape (not connected to the "string" escape). So it's \\.
To be more clear: you want your string to be "literally" \.(something
. To have that you need to escape the \
by putting another \
(otherwise your string would be .(
because the \
would escape the .
, so it wouldn't do anything). If you are curious, the .
in regexes means any character, but if you want to search for a .
(a dot), you have to escape it, and guess what you use? The \
:-)
If one day you'll have to program in C#, in C# you can solve this problem using the @"something"
. The @ disable escape "expansion" in a string. So @"\"
is a \
If you define your pattern as a Regex object using / /
as enclosures, the double escaping isn't necessary as it is never a string.
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