The modules allows:

• "http://www.google.com"
• "https://www.google.com"
• "http://google.com"
• "http://www.google.com/imghp"
• "http://g.co"

and disallows:

• "www.google"
• "google"
• "google#.com"
• "google-.co"

The problem is that it ALLOWS http://www.google when it shouldn't.

1.1.0 (master) has an updated repository field in package.json. @ianstormtaylor would you mind npm publishing it so we don't see this anymore:

npm WARN package.json [email protected] No repository field.

It fails on this URL https://chat..zulip.org.

https://chat..zulip.org --> true
https://chat.zulip..org --> true
https://chat.zulip.org.. --> true

and it should be false.

IMHO it should be an url ;)

From npm's package.json docs, Git urls can be of the form:

• git://github.com/user/project.git#commit-ish
• git+ssh://user@hostname:project.git#commit-ish
• git+ssh://user@hostname/project.git#commit-ish
• git+http://user@hostname/project/blah.git#commit-ish
• git+https://user@hostname/project/blah.git#commit-ish

Not sure it's appropriate to support these kinds of URLs, but figured I'd bring it up.

I was trying to test this library with GramTest, a grammar based test case generation tool (https://github.com/codelion/gramtest). I found that it fails to to check ftp URLs.

isUrl('ftp://username:password@hostname') //returns false

var matcher = /^\w+:\/\/([^\s\.]+\.\S{2}|localhost[\:?\d]*)\S*$/;

Will fail SO badly in so many cases: IDNs, modern TLDs, parens in URLs, punctuation at the end etc.

There's a much more powerful regexp in component/regexps.uri.

I understand this component doesn't really aim to properly parse URLs like linkify, but perhaps it's better to just use the regexps component.

I tried to fuzz the library again using GramTest, a grammar based test case generation tool (https://github.com/codelion/gramtest). I found that it fails to to check mailto URLs.

isUrl('mailto:[email protected]') // false

At the moment, is-url does not support urls like below:

• http://someserver/abc (without any dot)
• http://someserver:port/abc

This seems wrong to me:

$ node
> var isURL = require('is-url')
undefined
> isURL('http://localhost:3000/foo')
false
> 

The change from re.test(string) to string.match(re) result in a different behavior if string is undefined (calling .test on undefined will throw a TypeError).
Maybe put a guard like if (typeof string == 'string') return false to avoid that or consider bumping the major version as 1.2.3 can be considered as a change introducing a breaking change.

Would you please add a LICENSE file with your copyright information and the text of the MIT license? The MIT license specifies that the license text must accompany the source code. It also makes it easier on people like me who package up NodeJS modules for Linux distributions. Thanks!