You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
66 lines
1.5 KiB
Markdown
66 lines
1.5 KiB
Markdown
6 years ago
|
# safe-regex
|
||
|
|
|
||
|
|
detect potentially
|
||
|
|
[catastrophic](http://regular-expressions.mobi/catastrophic.html)
|
||
|
|
[exponential-time](http://perlgeek.de/blog-en/perl-tips/in-search-of-an-exponetial-regexp.html)
|
||
|
|
regular expressions by limiting the
|
||
|
|
[star height](https://en.wikipedia.org/wiki/Star_height) to 1
|
||
|
|
|
||
|
|
WARNING: This module merely *seems* to work given all the catastrophic regular
|
||
|
|
expressions I could find scouring the internet, but I don't have enough of a
|
||
|
|
background in automata to be absolutely sure that this module will catch all
|
||
|
|
exponential-time cases.
|
||
|
|
|
||
|
|
[](https://ci.testling.com/substack/safe-regex)
|
||
|
|
|
||
|
|
[](http://travis-ci.org/substack/safe-regex)
|
||
|
|
|
||
|
|
# example
|
||
|
|
|
||
|
|
``` js
|
||
|
|
var safe = require('safe-regex');
|
||
|
|
var regex = process.argv.slice(2).join(' ');
|
||
|
|
console.log(safe(regex));
|
||
|
|
```
|
||
|
|
|
||
|
|
```
|
||
|
|
$ node safe.js '(x+x+)+y'
|
||
|
|
false
|
||
|
|
$ node safe.js '(beep|boop)*'
|
||
|
|
true
|
||
|
|
$ node safe.js '(a+){10}'
|
||
|
|
false
|
||
|
|
$ node safe.js '\blocation\s*:[^:\n]+\b(Oakland|San Francisco)\b'
|
||
|
|
true
|
||
|
|
```
|
||
|
|
|
||
|
|
# methods
|
||
|
|
|
||
|
|
``` js
|
||
|
|
var safe = require('safe-regex')
|
||
|
|
```
|
||
|
|
|
||
|
|
## var ok = safe(re, opts={})
|
||
|
|
|
||
|
|
Return a boolean `ok` whether or not the regex `re` is safe and not possibly
|
||
|
|
catastrophic.
|
||
|
|
|
||
|
|
`re` can be a `RegExp` object or just a string.
|
||
|
|
|
||
|
|
If the `re` is a string and is an invalid regex, returns `false`.
|
||
|
|
|
||
|
|
* `opts.limit` - maximum number of allowed repetitions in the entire regex.
|
||
|
|
Default: `25`.
|
||
|
|
|
||
|
|
# install
|
||
|
|
|
||
|
|
With [npm](https://npmjs.org) do:
|
||
|
|
|
||
|
|
```
|
||
|
|
npm install safe-regex
|
||
|
|
```
|
||
|
|
|
||
|
|
# license
|
||
|
|
|
||
|
|
MIT
|