Kwargs

Python style keyword arguments for javascript!

Usage

Node.js

var kwargs = require('kwargs')

Browser

<script src="kwargs.min.js"></script>

Methods

kwargs(function, object, …)

Call a given function with a kwarg object. Any extra named params will be added to the argument list in the order they are read, followed by any extra arguments.

function letters(a, b, c) {
  return '' + a + b + c
}
 
kwargs(letters, {b: 'o', c: 'w', a: 'c'}) // 'cow'
kwargs(letters, {b: '-'}) // 'undefined-undefined'

Lets try adding some normal arguments now. Normal args are added after the last supplied kwarg, never before.

function foo(a, b, c, d) {
  return [a, b, c, d]
}
 
kwargs(foo, {a: 20, b: 30}, 40, 50) // [20, 30, 40, 50]
kwargs(foo, {d: 5}, 10, 15, 20) // [undefined, undefined, undefined, 5]

Magic arguments! If a function is created with an _args or __kwargs param, this module will use them as close as possible to python's *args and **kwargs. The main difference here is that the params must be named exactly as specified to be used. The _args param will be used as an array of all unused arguments. The __kwargs param will be an object of all unused kwargs passed to the module.

function magic(_args, __kwargs) {}
 
kwargs(magic, {a: 20, b: 30}, 40, 50)
// _args = [40, 50]
// __kwargs = {a: 20, b: 30}

Mix it up:

function meow(cat, milk, __kwargs) {}
 
kwargs(meow, {cat: 30, milk: 10, blah: 40})
// cat = 30
// milk = 10
// __kwargs = {blah: 40}

function meow(a, b, c, _args) {}
 
kwargs(meow, {a: 30}, 1, 2, 3, 4)
// a = 30
// b = 1
// c = 2
// _args = [3, 4]

kwargs.getNames(function)

Get the argument name array for a given function, mainly for internal use, exposed in case you need it for something.

function add(first, second, third) {}
 
kwargs.getNames(add) // ['first', 'second', 'third']

Install

With npm

npm install kwargs

License

(The MIT License)

Copyright (c) 2011-2012 Beau Sorensen mail@beausorensen.com

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.