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A command-line argument parser utility designed to parse command-line arguments.

Use complex parameters and define a argument signature.

command --param value1 value2

Use compact syntax.

command -p=value2

And combine parameters

command -pjk


Run the following

npm install argr --save

Quick Start

Import the definition

var Argr = require('argr');

Create in instance

var argr = Argr()

Define some simple options, to accept the following hello -ab and hello --option_a --option_b

  .option(['a', 'option_a'], 'Option A')
  .option(['b', 'option_b'], 'Option B')

Define an option with complex syntax specified with signature arguments: -g -50.2 232 where -g option will always expect two additional values following

  .option(['g', 'geocoord'], 'A geocoordinate', null, ['lat', 'lng'])

Define an option with compact syntax: -s=abc-def with default parameters

  .option(['s', 'string'], 'A string', 'mydefaultstring')

And initialize it (e.g. - /usr/local/bin/node hello -abc -g -50.2 232 -s=abc-def)

.init('/usr/local/bin/node hello -abc -g -50.2 232 -s=abc-def');

Full example:

var Argr = require('argr');

  .option(['a', 'option_a'], 'Option A')
  .option(['b', 'option_b'], 'Option B')
  .init('/usr/local/bin/node hello -ab');

You can retrieve the parameters like so

assert.equal(argr.get('a'), true);
assert.equal(argr.get('b'), true);

Undefined parameters are not ignored

assert.equal(argr.get('c'), true);

Access complex syntax with signatures as hash Objects

assert.equal(argr.get('g').lat, '-50.2');
assert.equal(argr.get('g').lng, '232');

Use compact syntax with {name}={value}

assert.equal(argr.get('s'), 'abc-def');

Argr Class

Create an instance of argument parser.

var Argr = require('argr');
var a = Argr().init(process.argv);


flag {Boolean}

A flag for command argument start, default true.

True assumes use of /usr/local/bin/node and starts parsing at index 2. False starts parsing at index 1.

Must be set before .init()

var a = Argr()
	.init('/usr/local/bin/node hello -?');

argr. useStrict(flag)

flag {Boolean}

A flag to throw Error on undefined options, default false.

var a = Argr()
	.init('/usr/local/bin/node hello -?');

An error is thrown if ? is not defined through argr.option() during initialization.

Must be set before .init()


Initialize, chainable

args {Mixed}

Object Create an argument parser instance from process.argv argument vector.

var Argr = require('argr');
var a = Argr().init(process.argv);

String Or create an argument parser from string.

var Argr = require('argr');
var a = Argr().init('/usr/local/bin/node hello -f tests/data/config.json');


Get command from argument vector.

var a = Argr().init('/use/local/bin/node hello -f tests/data/config.json');
assert(a.command() === 'hello');

argr.option(param, description, [values], [signature])

Define an options and its syntax. Arguments that are not define will be parsed anyway.


param {Mixed}

String A parameter name

// cmd -y
argr.option('y', 'Lorem ipsum')

Array ['a', 'apple', alternate-form...] parameter name(s) and aliases

// short: cmd -f
//  long: cmd --fruit
argr.option(['f', 'fruit'], 'A fruit')

description {String}

A description value

values {Mixed}

An optional set of default values

Boolean A single default Boolean if no argument was passed

Number A single default Number if no argument was passed

String A single default String if no argument was passed

Array A set of default values, intending to match a signature. Uses the signature to create a hash of values using the signature as keys and the Array as values.

signature {Array}

An optional argument signature. Specifying a signature will expect the next argument(s) to be values.

// cmd -g -50.32 74.2 
argr.option(['g', 'geocoords'], 'A set of geocoordinates', null, ['lat', 'lng'])

The option -g will expect lat and lng coordinates when used; argr.get('g') returns:

	'lat': '-50.32',
	'lng': '74.2'


Get a defined option parameter


Retrieves a full description of the defined parameters

	param: ['g', 'geocoords'],
	value: {Function},
	signature: ['lat', 'lng'],
	description: 'A set of geocoordinates'

param {Mixed}

String A name of a specific parameter

Array A set of acceptable parameter names or aliases


Get all defined options


All of the option definitions


Retrieve parameters according to the name of the parameter. Undefind parameters are returned as well but must still be prefixed with either - or -- (e.g. - --color).

name {String}

A name of a specific parameter

Combined parameters

var argr = Argr().init('/usr/local/bin/node cmd -zxvf');

Parameters can be combined for shorter syntax each will become parameters.

assert.equal(argr.get('z'), true);
assert.equal(argr.get('x'), true);
assert.equal(argr.get('v'), true);
assert.equal(argr.get('f'), true);

Undefined parameters are not ignored

Any undefined arguments will still be retrievable using .get('n') where 'n' is the name.

Complex syntax using signatures

var argr = Argr().init('/usr/local/bin/node cmd -g -50.32 74.2');
argr.option(['g', 'geocoords'], 'A set of geocoordinates', null, ['lat', 'lng'])

Using a signature will allow complex syntax returning the result as a hash where the keys are defined in the signature.

assert.equal(argr.get('g').lat, '-50.32');
assert.equal(argr.get('g').lng, '74.2');

Compact syntax

var argr = Argr().init('/usr/local/bin/node cmd -f=myfile.txt');

Compact syntax allows the use of [name]=[value] pairs

assert.equal(argr.get('f'), 'myfile.txt');


Copyright (c) 2014 Henry Tseng

Released under the MIT license. See LICENSE for details.

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