url-pattern

What is url-pattern?

The url-pattern npm package is a utility for matching URL patterns and extracting parameters from URLs. It is useful for routing in web applications, where you need to determine which code to execute based on the URL path.

What are url-pattern's main functionalities?

Pattern Matching

This feature allows you to define URL patterns and match them against actual URLs. The example demonstrates how to create a pattern for user IDs and match it against a URL, extracting the user ID as a parameter.

const UrlPattern = require('url-pattern');
const pattern = new UrlPattern('/users/:id');
const match = pattern.match('/users/123');
console.log(match); // { id: '123' }

Reverse URL Generation

This feature allows you to generate URLs from a pattern and a set of parameters. The example shows how to create a URL for a specific user ID using the pattern.

const UrlPattern = require('url-pattern');
const pattern = new UrlPattern('/users/:id');
const url = pattern.stringify({ id: '123' });
console.log(url); // '/users/123'

Wildcard Matching

This feature allows you to use wildcards in your URL patterns to match any sequence of characters. The example demonstrates how to match any file path under the '/files' directory.

const UrlPattern = require('url-pattern');
const pattern = new UrlPattern('/files/*');
const match = pattern.match('/files/images/photo.jpg');
console.log(match); // { _: 'images/photo.jpg' }

Other packages similar to url-pattern

path-to-regexp

The path-to-regexp package is another utility for matching URL patterns and extracting parameters. It is more flexible and powerful than url-pattern, supporting advanced pattern matching features like optional parameters and custom parameter patterns.

route-parser

The route-parser package provides similar functionality for defining and matching URL patterns. It is simpler and more lightweight compared to url-pattern, making it a good choice for smaller projects or when you need a minimal solution.

url-patterns

The url-patterns package is another alternative for URL pattern matching and parameter extraction. It offers a similar API to url-pattern but includes additional features like query string parsing and more advanced pattern matching capabilities.

README

url-pattern

easier than regex string matching patterns for urls and other strings.
turn strings into data or data into strings.

This is a great little library -- thanks!
michael

make pattern:

var pattern = new UrlPattern('/api/users(/:id)');

match pattern against string and extract values:

pattern.match('/api/users/10'); // {id: '10'}
pattern.match('/api/users'); // {}
pattern.match('/api/products/5'); // null

generate string from pattern and values:

pattern.stringify() // '/api/users'
pattern.stringify({id: 20}) // '/api/users/20'

• continuously tested in Node.js (0.12, 4.2.3 and 5.3) and all relevant browsers:
• tiny single file with just under 500 lines of simple, readable, maintainable code
• huge test suite passing with code coverage
• widely used
• supports CommonJS, AMD and browser globals
  • require('url-pattern')
  • use lib/url-pattern.js in the browser
  • sets the global variable UrlPattern when neither CommonJS nor AMD are available.
• very fast matching as each pattern is compiled into a regex exactly once
• zero dependencies
• customizable
• frequently asked questions
• npm package: npm install url-pattern
• bower package: bower install url-pattern
• pattern parser implemented using simple, combosable, testable parser combinators
• typescript typings

check out passage if you are looking for simple composable routing that builds on top of url-pattern

npm install url-pattern

bower install url-pattern

> var UrlPattern = require('url-pattern');

> var pattern = new UrlPattern('/v:major(.:minor)/*');

> pattern.match('/v1.2/');
{major: '1', minor: '2', _: ''}

> pattern.match('/v2/users');
{major: '2', _: 'users'}

> pattern.match('/v/');
null

> var pattern = new UrlPattern('(http(s)\\://)(:subdomain.):domain.:tld(\\::port)(/*)')

> pattern.match('google.de');
{domain: 'google', tld: 'de'}

> pattern.match('https://www.google.com');
{subdomain: 'www', domain: 'google', tld: 'com'}

> pattern.match('http://mail.google.com/mail');
{subdomain: 'mail', domain: 'google', tld: 'com', _: 'mail'}

> pattern.match('http://mail.google.com:80/mail');
{subdomain: 'mail', domain: 'google', tld: 'com', port: '80', _: 'mail'}

> pattern.match('google');
null

make pattern from string

> var pattern = new UrlPattern('/api/users/:id');

a pattern is immutable after construction.
none of its methods changes its state.
that makes it easier to reason about.

match pattern against string

match returns the extracted segments:

> pattern.match('/api/users/10');
{id: '10'}

or null if there was no match:

> pattern.match('/api/products/5');
null

patterns are compiled into regexes which makes .match() superfast.

named segments

:id (in the example above) is a named segment:

a named segment starts with : followed by the name.
the name must be at least one character in the regex character set a-zA-Z0-9.

when matching, a named segment consumes all characters in the regex character set a-zA-Z0-9-_~ %. a named segment match stops at /, ., ... but not at _, -, , %...

you can change these character sets. click here to see how.

if a named segment name occurs more than once in the pattern string, then the multiple results are stored in an array on the returned object:

> var pattern = new UrlPattern('/api/users/:ids/posts/:ids');
> pattern.match('/api/users/10/posts/5');
{ids: ['10', '5']}

optional segments, wildcards and escaping

to make part of a pattern optional just wrap it in ( and ):

> var pattern = new UrlPattern(
  '(http(s)\\://)(:subdomain.):domain.:tld(/*)'
);

note that \\ escapes the : in http(s)\\://. you can use \\ to escape (, ), : and * which have special meaning within url-pattern.

optional named segments are stored in the corresponding property only if they are present in the source string:

> pattern.match('google.de');
{domain: 'google', tld: 'de'}

> pattern.match('https://www.google.com');
{subdomain: 'www', domain: 'google', tld: 'com'}

* in patterns are wildcards and match anything. wildcard matches are collected in the _ property:

> pattern.match('http://mail.google.com/mail');
{subdomain: 'mail', domain: 'google', tld: 'com', _: 'mail'}

if there is only one wildcard then _ contains the matching string. otherwise _ contains an array of matching strings.

look at the tests for additional examples of .match

make pattern from regex

> var pattern = new UrlPattern(/^\/api\/(.*)$/);

if the pattern was created from a regex an array of the captured groups is returned on a match:

> pattern.match('/api/users');
['users']

> pattern.match('/apiii/test');
null

when making a pattern from a regex you can pass an array of keys as the second argument. returns objects on match with each key mapped to a captured value:

> var pattern = new UrlPattern(
  /^\/api\/([^\/]+)(?:\/(\d+))?$/,
  ['resource', 'id']
);

> pattern.match('/api/users');
{resource: 'users'}

> pattern.match('/api/users/5');
{resource: 'users', id: '5'}

> pattern.match('/api/users/foo');
null

stringify patterns

> var pattern = new UrlPattern('/api/users/:id');

> pattern.stringify({id: 10})
'/api/users/10'

optional segments are only included in the output if they contain named segments and/or wildcards and values for those are provided:

> var pattern = new UrlPattern('/api/users(/:id)');

> pattern.stringify()
'/api/users'

> pattern.stringify({id: 10})
'/api/users/10'

wildcards (key = _), deeply nested optional groups and multiple value arrays should stringify as expected.

an error is thrown if a value that is not in an optional group is not provided.

an error is thrown if an optional segment contains multiple params and not all of them are provided. one provided value for an optional segment makes all values in that optional segment required.

look at the tests for additional examples of .stringify

customize the pattern syntax

finally we can completely change pattern-parsing and regex-compilation to suit our needs:

> var options = {};

let's change the char used for escaping (default \\):

> options.escapeChar = '!';

let's change the char used to start a named segment (default :):

> options.segmentNameStartChar = '$';

let's change the set of chars allowed in named segment names (default a-zA-Z0-9) to also include _ and -:

> options.segmentNameCharset = 'a-zA-Z0-9_-';

let's change the set of chars allowed in named segment values (default a-zA-Z0-9-_~ %) to not allow non-alphanumeric chars:

> options.segmentValueCharset = 'a-zA-Z0-9';

let's change the chars used to surround an optional segment (default ( and )):

> options.optionalSegmentStartChar = '[';
> options.optionalSegmentEndChar = ']';

let's change the char used to denote a wildcard (default *):

> options.wildcardChar = '?';

pass options as the second argument to the constructor:

> var pattern = new UrlPattern(
  '[http[s]!://][$sub_domain.]$domain.$toplevel-domain[/?]',
  options
);

then match:

> pattern.match('http://mail.google.com/mail');
{
  sub_domain: 'mail',
  domain: 'google',
  'toplevel-domain': 'com',
  _: 'mail'
}

frequently asked questions

how do i match the query part of an URL ?

the query part of an URL has very different semantics than the rest. url-pattern is not well suited for parsing the query part.

there are good existing libraries for parsing the query part of an URL. https://github.com/hapijs/qs is an example. in the interest of keeping things simple and focused i see no reason to add special support for parsing the query part to url-pattern.

i recommend splitting the URL at ?, using url-pattern to parse the first part (scheme, host, port, path) and using https://github.com/hapijs/qs to parse the last part (query).

how do i match an IP ?

you can't exactly match IPs with url-pattern so you have to fall back to regexes and pass in a regex object.

here's how you do it

contributing

license: MIT