Make a regex from a string that only matches itself

Question

I want a way to generate a regex from a string that will match only the original string.

i.e.

myRegexGenerator('babies/canfly?a=probably-not');
// returns an equivalent to /^babies\/canfly\?a=probably-not$/

Just [escape](http://stackoverflow.com/questions/3561493/is-there-a-regexp-escape-function-in-javascript) it and add `^` and `$`. — georg, Aug 22 '16 at 08:22
Either do what georg said or just compare the strings directly without using a regex, if the latter is doable in whatever code you've written (I'm sure you have your reasons). — Jason C, Aug 22 '16 at 08:25
To search strings inside other strings you have methods like *indexOf()*, if you need to count the time the string matches you could easily do it with a loop and *indexOf()* as you can give a starting index as second parameter. — Mario Santini, Aug 22 '16 at 08:28
The purpose is to make a function which can accept either a string or a regex as an argument, but internally uses a regex equivalent of that argument, for url path matching. — theonlygusti, Aug 22 '16 at 10:23

score 1 · Answer 1 · answered Aug 22 '16 at 08:40

You basically just need to escape any special regex characters. Then create a RegExp object.

var input = 'babies/canfly?a=probably-not';
new RegExp(input.replace(/[^$]/g, "\$&"));

Obviously the more special codes you catch and escape before making the RegExp the more robust it will be to different inputs. You can use a reference like regular-expressions.info to make sure you cover everything. Or you can just cover whatever characters you know are possible.

Make a regex from a string that only matches itself

1 Answers1