Turn a path string such as
/user/:name
into a regular expression.
npm install path-to-regexp --save
var pathToRegexp = require('path-to-regexp')
// pathToRegexp(path, keys?, options?)
// pathToRegexp.parse(path)
// pathToRegexp.compile(path)
- path A string, array of strings, or a regular expression.
- keys An array to be populated with keys found in the path.
- options
- sensitive When
true
the regexp will be case sensitive. (default:false
) - strict When
true
the regexp allows an optional trailing delimiter to match. (default:false
) - end When
false
the regexp will match the beginning instead of the entire string. (default:true
) - Advanced options (use for non-pathname strings, e.g. host names):
- delimiter The default delimiter for segments. (default:
'/'
) - endsWith Optional character, or list of characters, to treat as "end" characters.
- delimiters List of characters to consider delimiters when parsing. (default:
'./'
)
- delimiter The default delimiter for segments. (default:
- sensitive When
var keys = []
var re = pathToRegexp('/foo/:bar', keys)
// re = /^\/foo\/([^\/]+?)\/?$/i
// keys = [{ name: 'bar', prefix: '/', delimiter: '/', optional: false, repeat: false, pattern: '[^\\/]+?' }]
Please note: The RegExp
returned by path-to-regexp
is intended for ordered data (e.g. pathnames, hostnames). It does not handle arbitrary data (e.g. query strings, URL fragments, JSON, etc).
The path argument is used to define parameters and populate the list of keys.
Named parameters are defined by prefixing a colon to the parameter name (:foo
). By default, the parameter will match until the following path segment.
var re = pathToRegexp('/:foo/:bar')
// keys = [{ name: 'foo', prefix: '/', ... }, { name: 'bar', prefix: '/', ... }]
re.exec('/test/route')
//=> ['/test/route', 'test', 'route']
Please note: Parameter names must be made up of "word characters" ([A-Za-z0-9_]
).
Parameters can be suffixed with a question mark (?
) to make the parameter optional.
var re = pathToRegexp('/:foo/:bar?')
// keys = [{ name: 'foo', ... }, { name: 'bar', delimiter: '/', optional: true, repeat: false }]
re.exec('/test')
//=> ['/test', 'test', undefined]
re.exec('/test/route')
//=> ['/test', 'test', 'route']
Tip: If the parameter is the only value in the segment, the prefix is also optional.
Parameters can be suffixed with an asterisk (*
) to denote a zero or more parameter matches. The prefix is taken into account for each match.
var re = pathToRegexp('/:foo*')
// keys = [{ name: 'foo', delimiter: '/', optional: true, repeat: true }]
re.exec('/')
//=> ['/', undefined]
re.exec('/bar/baz')
//=> ['/bar/baz', 'bar/baz']
Parameters can be suffixed with a plus sign (+
) to denote a one or more parameter matches. The prefix is taken into account for each match.
var re = pathToRegexp('/:foo+')
// keys = [{ name: 'foo', delimiter: '/', optional: false, repeat: true }]
re.exec('/')
//=> null
re.exec('/bar/baz')
//=> ['/bar/baz', 'bar/baz']
All parameters can be provided a custom regexp, which overrides the default match ([^\/]+
). For example, you can match digits in the path:
var re = pathToRegexp('/icon-:foo(\\d+).png')
// keys = [{ name: 'foo', ... }]
re.exec('/icon-123.png')
//=> ['/icon-123.png', '123']
re.exec('/icon-abc.png')
//=> null
Please note: Backslashes need to be escaped with another backslash in strings.
It is possible to write an unnamed parameter that only consists of a matching group. It works the same as a named parameter, except it will be numerically indexed.
var re = pathToRegexp('/:foo/(.*)')
// keys = [{ name: 'foo', ... }, { name: 0, ... }]
re.exec('/test/route')
//=> ['/test/route', 'test', 'route']
The parse function is exposed via pathToRegexp.parse
. This will return an array of strings and keys.
var tokens = pathToRegexp.parse('/route/:foo/(.*)')
console.log(tokens[0])
//=> "/route"
console.log(tokens[1])
//=> { name: 'foo', prefix: '/', delimiter: '/', optional: false, repeat: false, pattern: '[^\\/]+?' }
console.log(tokens[2])
//=> { name: 0, prefix: '/', delimiter: '/', optional: false, repeat: false, pattern: '.*' }
Note: This method only works with strings.
Path-To-RegExp exposes a compile function for transforming a string into a valid path.
var toPath = pathToRegexp.compile('/user/:id')
toPath({ id: 123 }) //=> "/user/123"
toPath({ id: 'café' }) //=> "/user/caf%C3%A9"
toPath({ id: '/' }) //=> "/user/%2F"
toPath({ id: ':/' }) //=> "/user/%3A%2F"
toPath({ id: ':/' }, { encode: (value, token) => value }) //=> "/user/:/"
var toPathRepeated = pathToRegexp.compile('/:segment+')
toPathRepeated({ segment: 'foo' }) //=> "/foo"
toPathRepeated({ segment: ['a', 'b', 'c'] }) //=> "/a/b/c"
var toPathRegexp = pathToRegexp.compile('/user/:id(\\d+)')
toPathRegexp({ id: 123 }) //=> "/user/123"
toPathRegexp({ id: '123' }) //=> "/user/123"
toPathRegexp({ id: 'abc' }) //=> Throws `TypeError`.
Note: The generated function will throw on invalid input. It will do all necessary checks to ensure the generated path is valid. This method only works with strings.
Path-To-RegExp exposes the two functions used internally that accept an array of tokens.
pathToRegexp.tokensToRegExp(tokens, keys?, options?)
Transform an array of tokens into a matching regular expression.pathToRegexp.tokensToFunction(tokens)
Transform an array of tokens into a path generator function.
name
The name of the token (string
for named ornumber
for index)prefix
The prefix character for the segment (/
or.
)delimiter
The delimiter for the segment (same as prefix or/
)optional
Indicates the token is optional (boolean
)repeat
Indicates the token is repeated (boolean
)partial
Indicates this token is a partial path segment (boolean
)pattern
The RegExp used to match this token (string
)
Path-To-RegExp breaks compatibility with Express <= 4.x
:
- RegExp special characters can only be used in a parameter
- Express.js 4.x used all
RegExp
special characters regardless of position - this considered a bug
- Express.js 4.x used all
- Parameters have suffixes that augment meaning -
*
,+
and?
. E.g./:user*
- No wildcard asterisk (
*
) - use parameters instead ((.*)
)
Includes a .d.ts
file for TypeScript users.
You can see a live demo of this library in use at express-route-tester.
MIT