named-regexp-groups

> Regular expressions with named capture groups and named back-references


Create a named capture group with (?.) or (:.) when using
a RegExp. The methods of RegExp are supported excluding compile and toString.
Use named back-references using (?&name) to include already defined named pattern.

* Installation
* Usage
* exec
* test
* String.replace
* String.match
* String.split
* ES7
* License

Installation

npm install --save named-regexp-groups

Usage

``js
import NamedRegExp from 'named-regexp-groups'
//or
const NamedRegExp = require('named-regexp-groups')

// as string
var r = new NamedRegExp('(?foo)(?)(-)(?:wat)(?(?:na)+)(?&na)')
// or as regex
var r = new NamedRegExp(/(:foo)(:)(-)(?:wat)(:(?:na)+)(:&na)/)

r.source
// => r.source === '(foo)([^]+)(-)(?:wat)((?:na)+)((?:na)+)'
`

For nodejs < v5.0 core-js polyfills are required.
Use npm i -S core-js in your project and add:

`js
// for node < v0.11
require('core-js/es6/object')
// for node < v5.0
require('core-js/es6/string')
require('core-js/es6/symbol')
`

$3

`js
var r = new NamedRegExp('(?foo)(?bar)(-)(?:wat)(?(?:na)+)(?&na)')
r.exec('nanafoobar-watnana')
// => [ 'foobar-watnana', 'foo', 'bar', '-', 'na', 'na',
// index: 4,
// input: 'nanafoobar-watnana',
// groups: { foo: 'foo', bar: 'bar', '0': '-', na: 'na', '1': 'na' } ]
`

$3

`js
r = new NamedRegExp('(?foo)(bar)(?:waah)')
r.source
// => '(foo)(bar)(?:waah)'
r.test('nanafoobarwaah')
// => true
`

$3

If using a string as replacement use $+{name} to define the placeholder for the capture group.
This follows the Syntax of [PCRE Named backreferences][].

`js
var r = new NamedRegExp(/(:\d+)-(:\d+)-(:\d+)/)

// ---- using strings
'2017-01-02'.replace(r, 'day: $+{day}, month: $+{month}, year: $+{year}')
// => 'day: 02, month: 01, year: 2017')

// ---- using function
'2016-11-22'.replace(r, function () { // take care of NOT using an arrow function here!
var args = [].slice.call(arguments)
var g = this.groups
return day: ${args[g.day]}, month: ${args[g.month]}, year: ${args[g.year]}
})
// => 'day: 22, month: 11, year: 2017')
`

$3

`js
r = new NamedRegExp('(?foo)(bar)(?:waah)')
'nanafoobarwaah'.match(r)
// => [ 'foobarwaah', 'foo', 'bar',
// index: 4, input: 'nanafoobarwaah',
// groups: { '0': 'bar', foo: 'foo' } ]
`

$3

`js
r = new NamedRegExp('(?foo)')
'nanafoobarwaah'.split(r)
// => [ 'nana', 'foo', 'barwaah' ]
`

ES7

The proposed TC39 proposal-regexp-named-groups is finding it's way into the standard.
Chrome>=64 already supports named groups. Maybe node>=10 soon as well...

Paste this into Chrome>=64

`js
r = new RegExp(/(?foo)(?bar)(-)(?:wat)(?(?:na)+)/);
o = r.exec('nanafoobar-watnana')
//> (5) ["foobar-watnana", "foo", "bar", "-", "na",
//> index: 4, input: "nanafoobar-watnana",
//> groups: {foo: "foo", bar: "bar", na: "nana"}]
``

License

Software is released under [MIT][license].

[license]: ./LICENSE
[PCRE Named backreferences]: http://perldoc.perl.org/perlretut.html#Named-backreferences