args2

You can easily handle arguments of your own function.

install

npm install args2

use case

This Document is written in coffeeScript, but it also works with javascript.

case A

before

sampleFunction = (uri)->
  if typeof uri is 'undefined'
    throw new Error('undefined is not a valid uri or options object.')

after

sampleFunction = ->
  args = new args2(arguments)
  uri = args.str(true,'undefined is not a valid uri or options object.')

case B

before

sampleFunction = ->
  args = Array::slice.call(arguments, 0)
  callback = args.pop()
  if typeof callback isnt 'function'
    args.push callback
  options = if args.length then args.shift() else {}
  options = if typeof callback is 'function' then options else callback
  options = if options == null then {} else options
  if typeof callback is 'function'
    callback(null,options)
    return
  else
    return options

after

sampleFunction = ->
  args = new args2(arguments)
  callback = args.func()
  options = args.obj(false,{})
  if callback
    callback(null,options)
    return
  else
    return options

Document

constructor

args = new args2(arguments)

Always use "arguments" as argument

---

str(required,default_value)

fn = ->
  args = new args2(arguments)
  text1 = args.str(true)
  text2 = args.str(false,'default_value ')
  text3 = args.str()
  return text1 + text2 + text3
 
console.log fn('hello ','world ','and you')
# result: hello world and you 
console.log fn('hello ','world ')
# result: hello world undefined 
console.log fn('hello ')
# result: hello default_value undefined 
console.log fn()
# throw error: String argument required 

When required is true The second argument becomes an error message

sampleFunction = ->
  args = new args2(arguments)
  text1 = args.str(true,'custom message')
sampleFunction()
# throw error: custom message 

---

There are various similar methods

• ### num(required,default_value)
• ### obj(required,default_value)
• ### array(required,default_value)
• ### bool(required,default_value)
• ### func(required,default_value)
• ### other(required,default_value)

---

There are various alias too

• ### string(required,default_value)
• ### number(required,default_value)
• ### object(required,default_value)
• ### arr(required,default_value)
• ### boolean(required,default_value)
• ### function(required,default_value)

---

rStr(required,default_value)

Method with "r" at the head gets the last argument

fn = ->
  args = new args2(arguments)
  text2 = args.rStr(true)
  text1 = args.str()
  return text1 + text2
console.log fn('hello ','world ','and you')
# result: 'hello and you' 
console.log fn('hello ','world ')
# result: 'hello world ' 
console.log fn('hello ')
# result: 'undefinedhello ' 
console.log fn()
# throw error: String argument required 

---

There are various similar methods

• ### rNum(required,default_value)
• ### rObj(required,default_value)
• ### rAarray(required,default_value)
• ### rBool(required,default_value)
• ### rFunc(required,default_value)
• ### rOther(required,default_value)

There are various alias too

• ### rNumber(required,default_value)
• ### rObject(required,default_value)
• ### rArr(required,default_value)
• ### rBoolean(required,default_value)
• ### rFunction(required,default_value)
• ### rCallback(required,default_value)

---

shift

New in version 1.1.

It is a method similar to Array.prototype.shift ()
Removes the first element from the array and returns that element.

fn = ->
  args = new args2(arguments)
  text = args.shift()
  return text
console.log fn('one','two','three') # one 

pop

New in version 1.1.

It is a method similar to Array.prototype.pop ()
Removes the last element from the array and returns that element.

fn = ->
  args = new args2(arguments)
  text = args.pop()
  return text
console.log fn('one','two','three') # three 

args2.bridge(fn, arguments [,argument_to_add...])

When you are creating classes and functions I want to pass the argument as it is to another function In that case, please use "bridge"
This is a class method

{bridge} = require 'args2'
# or 
args2.bridge

sum = ->
  args = new args2(arguments)
  return args.nums.reduce (p,c)-> p + c
console.log  sum(1,2,3) #6 
 
bridgeFunction1 = ->
  args2.bridge(sum,arguments)
console.log  bridgeFunction1(2,3,4)# 9 
 
bridgeFunction2 = ->
  args2.bridge(sum,arguments,1)
console.log  bridgeFunction2(2,3,4)# 10 
 
bridgeFunction3 = ->
  args2.bridge(sum,arguments,10,100,1000)
console.log  bridgeFunction3(2,3,4)# 1119 

args2.pass(fn, arguments [,argument_to_add...])

'pass' is alias for 'bridge'
This is a class method

bridge(fn)

New in version 1.1.

This is the instance version of args2.bridge. After manipulating the arguments you can pass it to the next method

fn = ->
  args = new args2(arguments)
  args.shift()
  args.bridge(console.log)
 
fn('one','two','three') # two three 

fn = ->
  args = new args2(arguments)
  args.pop()
  args.bridge(console.log)
 
fn('one','two','three') # one two 

fn = ->
  args = new args2(arguments)
  args.str()
  args.bridge(console.log)
 
fn({a:'a'},'one',true) # {a:'a'} true 

pass(fn)

New in version 1.1.

'pass' is alias for 'bridge'