Don't understand where my "Unnecessary escape character" error comes from

Question

I have a url that contains two values, a keyword and a location name. The keyword comes after the '/r/' and the location after the '/l/'.
E.g: localhost:3000/search/r/keyword/l/location

To get only the value after the '/r/' (keyword) and the value after the '/l/' (location); I'm doing the following Regexr:

var cutResult = window.location.href.match(/\br\/\b(\b[^\/]+\b)/gi);
var cutLocation = window.location.href.match(/\b\/l\/\b(\b[^\/]+\b)/gi);

This does the trick, however, React returns following message:

Unnecessary escape character: / no-useless-escape

What causes the error?

It is unnecessary to escape `/` inside a `[...]` character class. So just `[^/]+` will do. Also you seem to have a few too many `\b`s... — Niet the Dark Absol, Jan 29 '19 at 14:19
The [^/]+ did the trick. However I don't know about the \b; I used a [regexr generator](https://regexr.com/) to understand and create the above expression. — Cédric Bloem, Jan 29 '19 at 14:22
Well personally I wouldn't use regex for this, I'd `.split("/")` and then scan through the pieces to find `r` or `l` and mark the next item as that value. — Niet the Dark Absol, Jan 29 '19 at 14:22

score 3 · Answer 1 · answered Mar 29 '19 at 09:45

You do not need to escape most of the characters inside a character class (inside [...]) only a few:

In most regex flavors, the only special characters or metacharacters inside a character class are the closing bracket ], the backslash \, the caret ^, and the hyphen -. The usual metacharacters are normal characters inside a character class, and do not need to be escaped by a backslash. To search for a star or plus, use [+*]. Your regex will work fine if you escape the regular metacharacters inside a character class, but doing so significantly reduces readability.

Don't understand where my "Unnecessary escape character" error comes from

1 Answers1