@smikhalevski/route-pattern
v1.0.1
Published
The path pattern parser, that supports named variables, variable constraints, bash-like alternation, regular expressions, and wildcards.
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route-pattern
The path pattern parser, that supports named variables, variable constraints, bash-like alternation, regular expressions, and wildcards.
This package is tiny, just 2.2 kB gzipped including dependencies.
npm install --save-prod @smikhalevski/route-pattern
Usage
import {convertPatternToRegExp} from '@smikhalevski/route-pattern';
const re = convertPatternToRegExp('/(\\d+)/:foo{ bar, qux }');
const match = re.exec('/123/bar');
console.log(match?.groups?.foo); // → 'bar'
The support of named capturing groups is not required from the environment.
Features
/foo/bar
is a literal path that is matched as is.
Spaces, tabs, and newlines are ignored, so / foo / bar
is the same as /foo/bar
, and /foo bar
is the same
as /foobar
(note the absent spaces).
If you want to preserve spaces, use quotes: /" foo bar"
.
Regular expression
(\\d+)
declares a regular expression, spaces have meaning inside a regular expression.
RegExps can contain a named capturing groups which are merged with variables. For example, /:foo/(?<bar>abc)
would
match /123/abc
and groups would be {foo: '123', bar: 'abc'}
.
Wildcards
*
declares a wildcard that matches everything except the path separator. For example, /foo/*/bar
would
match /foo/okay/bar
and /foo//bar
but won't match /foo/no/sir/bar
.
**
declares a greedy wildcard that matches everything, even path separators. For example, /foo/**/bar
would
match /foo/okay/bar
, /foo//bar
and /foo/no/sir/bar
.
If you want to match at least one character, use a regular expression instead of a wildcard. For
example, /foo/([^/]+)/bar
would match /foo/okay/bar
and won't match /foo//bar
.
Alternation
{ foo, bar }
declares an alternation: foo
or bar
.
Alternation supports nesting, for example /foo{ -bar, /(\\d+)/qux }
would match /foo-bar
and /foo/123/qux
.
Variables
:foo
declares a variable. Variable name should match ^[A-Za-z0-9$_]+$
.
By default, variables match everything except the path separator.
A single pattern that immediately follows the variable declaration is treated as a variable constraint. For example,:foo bar
and :foo"bar"
would both read variable foo
and treat bar
as its string literal constraint.
:foo(\\d+)
declares a variable whose value is constrained by a regular expression.
:foo{ a, b }
declares a variable whose value is constrained by an alternation.
:foo{**}
variables can be constrained with wildcards.
Variables can be nested through an alternation: /aaa/ :foo{ /bbb, /ccc/:bar }
.
Variables are not treated as constraints for other variables. For example, :foo:bar{abc}
would match 123abc
and
groups would be {foo: '123', bar: 'abc'}
.