focusj/CoffeeScript-CheetSheets

## CoffeeScript-CheetSheets
# CoffeeScript CheetSheet#

## Declaration

### there is no vars, and no need to add ';' and the end
    i = 10
    str = "hello world"
    [firstName, lastName] = ["kang", "wang"]


### define a function, no need to add the keyword 'function', -> is enough
    fn = (param) -  ...

### Splats: define a function with multi parameters
    fn = (parm1, parm1, params...) ->
        ...

    params = ["value1", "value2", "value3", "value4"]
    fn(params)
    fn("value", params)
    fn("value", "value", params)

### define an Array
    arr = [
       "element1"
       "element2"
    ]

### define an object
    obj =
       first: 1
       second:
          second_1: 1
          second_2: 2
       third: 3

    $('.element').attr class: "active"


### lexical scoping and variable safity.
    outter = 10
    scope = ->
       inner = 10
>>	  outter = 20
    inner = 20


## String Interpolation

### mixin variable and function in string defination
    str = "variable 1: #{var1}, function 1 returns: #{fn()}"

    str = "
       today is Sunday
       so tomorrow is
       Monday
    "

    htmlTpl = """
       <html>
          <body>
             <h1>Hello World</h1>
          </body>
       </html>
    """


## Destructuring Assignment

    [var1, var2] = [value1, value2]

### use on object unapply
    {firstName, lastName} = {firstName: "Kang", lastName: "Wang"}

### use for a function multi-returns
    location () ->
       ["US", "LA", "Berkly"]

    [county, province, city] = location()
    [start, end] = "hello, world".split ","

### use to skip some useless bucket ...
    [start, ..., end] = [1, 2, 3, 4, 5]

### destructuring constructor
    class Person
       constructor: (options) ->
       {@name, @age, @height} = options

    tim = new Person age: 4


## condition control

### if else then
    "do something" if true

    if true and true
       "do something"
    else
       "do other things"

    if true then "do something" else "do other things"


## for loop control

### for loop while until
    print ele for ele in [1, 2, 3, 4]

    prints i, ele for ele in [1, 2, 3, 4]

    print ele for ele in [1, 2, 3, 4] when ele / 2 != 1

    countDown = (num for num in [10 .. 1] by 2)

### loop an object
    prints k, v for k, v of kid

    print ele until ele > 10

    print ele while ele > 10

### do keywords
    for filename in list
       do (filename) ->
          fs.readFile filename, (err, contents) ->
             compile filename, contents.toString()

    for ele in [1, 2, 3, 4]
       do print ele


## try .. catch .. expression

    try
    	  fn(1)
    catch error
    	  error
    finally
    	  then


## try .. catch .. expression

### Array Operations
    numSerials = [10 .. 0]

    start = numSerials[0..2]

    end = numSerials[0..-2]

    end = numSerials[..]

    umSerials[0..2] = [1, 2, 3]

### use expression as much as possible
    globals = (name for name of window)[0...10]


## Existantial Operator ?, ?.

### '?' means varaible is null or undefiend
    solipsism = true if mind? and world?

    speed = 0
    speed ?= 15

    footprints = yeti ? "bear"

### '?.' usef for assessing object attribute
    kid.brother?.sister


## switch when else

     switch day
     	when "Mon" then ""
     	when "Tue" then ""
     	else "WTF"

     day = switch day
     	when "Mon" then ""
     	when "Tue" then ""
     	else "WTF"


## object oriented

### use =>   to bind this in scope
     Account = (customer, cart) ->
       @customer = customer
       @cart = cart

       $('.shopping_cart').bind 'click', (event) =>
         @customer.purchase @cart

     Account2 = (customer, cart) ->
       @customer = customer
       @cart = cart

       $('.shopping_cart').bind 'click', (event) ->
         @customer.purchase @cart


### bind function to an exists function
    Array::map = ->
       "..."

## some sugar

### chained comparasion
    cholesterol = 127
    healthy = 200 > cholesterol > 60

### block regular expression
    OPERATOR = /// ^ (
      ?: [-=]>             # function
       | [-+*/%<>&|^!?=]=  # compound assign / compare
       | >>>=?             # zero-fill right shift
       | ([-+:])\1         # doubles
       | ([&|<>])\2=?      # logic / shift
       | \?\.              # soak access
       | \.{2,3}           # range or splat
    ) ///

### embeded javascript
    fn = `function fn() {}`


## operators and alias in CoffeeScript

    CoffeeScript	             JavaScript
      is	                        ===
      isnt	                        !==
      not	                        !
      and	                        &&
      or	                        ||
      true, yes, on	                true
      false, no, off	            false
      @, this	                    this
      of	                         in
      in	                   no JS equivalent
      a ** b	               Math.pow(a, b)
      a // b	               Math.floor(a / b)
      a %% b	               (a % b + b) % b


##  multi etends example
     moduleKeywords = ['extended', 'included']

     class Trait
     	@mixin: (obj) =>
     		for key, value of obj when key not in moduleKeywords
     			@::[key] = value

     		obj.with?.apply(@)
     		this

     	@with: (objs ...) ->
     		@mixin obj for obj in objs


     MongoDao =
     	find: () -> console.log("find items in mongo")

     	create: () -> console.log("delete item in mongo")

     class UserDao extends Trait
     	@with Daoable, MongoDao
	# CoffeeScript CheetSheet#

	## Declaration

	### there is no vars, and no need to add ';' and the end
	i = 10
	str = "hello world"
	[firstName, lastName] = ["kang", "wang"]


	### define a function, no need to add the keyword 'function', -> is enough
	fn = (param) - ...

	### Splats: define a function with multi parameters
	fn = (parm1, parm1, params...) ->
	...

	params = ["value1", "value2", "value3", "value4"]
	fn(params)
	fn("value", params)
	fn("value", "value", params)

	### define an Array
	arr = [
	"element1"
	"element2"
	]

	### define an object
	obj =
	first: 1
	second:
	second_1: 1
	second_2: 2
	third: 3

	$('.element').attr class: "active"


	### lexical scoping and variable safity.
	outter = 10
	scope = ->
	inner = 10
	>> outter = 20
	inner = 20



	## String Interpolation

	### mixin variable and function in string defination
	str = "variable 1: #{var1}, function 1 returns: #{fn()}"

	str = "
	today is Sunday
	so tomorrow is
	Monday
	"

	htmlTpl = """
	<html>
	<body>
	<h1>Hello World</h1>
	</body>
	</html>
	"""


	## Destructuring Assignment

	[var1, var2] = [value1, value2]

	### use on object unapply
	{firstName, lastName} = {firstName: "Kang", lastName: "Wang"}

	### use for a function multi-returns
	location () ->
	["US", "LA", "Berkly"]

	[county, province, city] = location()
	[start, end] = "hello, world".split ","

	### use to skip some useless bucket ...
	[start, ..., end] = [1, 2, 3, 4, 5]

	### destructuring constructor
	class Person
	constructor: (options) ->
	{@name, @age, @height} = options

	tim = new Person age: 4


	## condition control

	### if else then
	"do something" if true

	if true and true
	"do something"
	else
	"do other things"

	if true then "do something" else "do other things"



	## for loop control

	### for loop while until
	print ele for ele in [1, 2, 3, 4]

	prints i, ele for ele in [1, 2, 3, 4]

	print ele for ele in [1, 2, 3, 4] when ele / 2 != 1

	countDown = (num for num in [10 .. 1] by 2)

	### loop an object
	prints k, v for k, v of kid

	print ele until ele > 10

	print ele while ele > 10

	### do keywords
	for filename in list
	do (filename) ->
	fs.readFile filename, (err, contents) ->
	compile filename, contents.toString()

	for ele in [1, 2, 3, 4]
	do print ele


	## try .. catch .. expression

	try
	fn(1)
	catch error
	error
	finally
	then


	## try .. catch .. expression

	### Array Operations
	numSerials = [10 .. 0]

	start = numSerials[0..2]

	end = numSerials[0..-2]

	end = numSerials[..]

	umSerials[0..2] = [1, 2, 3]

	### use expression as much as possible
	globals = (name for name of window)[0...10]



	## Existantial Operator ?, ?.

	### '?' means varaible is null or undefiend
	solipsism = true if mind? and world?

	speed = 0
	speed ?= 15

	footprints = yeti ? "bear"

	### '?.' usef for assessing object attribute
	kid.brother?.sister



	## switch when else

	switch day
	when "Mon" then ""
	when "Tue" then ""
	else "WTF"

	day = switch day
	when "Mon" then ""
	when "Tue" then ""
	else "WTF"


	## object oriented

	### use => to bind this in scope
	Account = (customer, cart) ->
	@customer = customer
	@cart = cart

	$('.shopping_cart').bind 'click', (event) =>
	@customer.purchase @cart

	Account2 = (customer, cart) ->
	@customer = customer
	@cart = cart

	$('.shopping_cart').bind 'click', (event) ->
	@customer.purchase @cart


	### bind function to an exists function
	Array::map = ->
	"..."

	## some sugar

	### chained comparasion
	cholesterol = 127
	healthy = 200 > cholesterol > 60

	### block regular expression
	OPERATOR = /// ^ (
	?: [-=]> # function
	\| [-+*/%<>&\|^!?=]= # compound assign / compare
	\| >>>=? # zero-fill right shift
	\| ([-+:])\1 # doubles
	\| ([&\|<>])\2=? # logic / shift
	\| \?\. # soak access
	\| \.{2,3} # range or splat
	) ///

	### embeded javascript
	fn = `function fn() {}`



	## operators and alias in CoffeeScript

	CoffeeScript JavaScript
	is ===
	isnt !==
	not !
	and &&
	or \|\|
	true, yes, on true
	false, no, off false
	@, this this
	of in
	in no JS equivalent
	a ** b Math.pow(a, b)
	a // b Math.floor(a / b)
	a %% b (a % b + b) % b


	## multi etends example
	moduleKeywords = ['extended', 'included']

	class Trait
	@mixin: (obj) =>
	for key, value of obj when key not in moduleKeywords
	@::[key] = value

	obj.with?.apply(@)
	this

	@with: (objs ...) ->
	@mixin obj for obj in objs


	MongoDao =
	find: () -> console.log("find items in mongo")

	create: () -> console.log("delete item in mongo")

	class UserDao extends Trait
	@with Daoable, MongoDao