coffeescript.md

# When using a JavaScript loop to generate functions, 
# it's common to insert a closure wrapper in order to ensure that loop variables are closed over, 
# and all the generated functions don't just share the final values.
# CoffeeScript provides the do keyword,
# which immediately invokes a passed function, forwarding any arguments.

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

# To step through a range comprehension in fixed-size chunks, use by, for example:

evens = (x for x in [0..10] by 2)

# Health conscious meal.
foods = ['broccoli', 'spinach', 'chocolate']
eat food for food in foods when food isnt 'chocolate'

loop hash using of

# Comprehensions can also be used to iterate over the keys and values in an object.
# Use of to signal comprehension over the properties of an object instead of the values in an array.

yearsOld = max: 10, ida: 9, tim: 11

ages = for child, age of yearsOld
  "#{child} is #{age}

CoffeeScript	JavaScript
is	===
isnt	!==
not	!
and	&&
or	ll
true,yes, on	true
false,	no, off
@,this	this
of	in
in	no JS equivalent

# It's a little difficult to check for the existence of a variable in JavaScript.
# if (variable) ... comes close, but fails for zero, the empty string, and false.
# CoffeeScript's existential operator ? returns true unless a variable is null or undefined,
# which makes it analogous to Ruby's nil?
# It can also be used for safer conditional assignment than ||= provides,
# for cases where you may be handling numbers or strings.

speed ?= 15

footprints = yeti ? "bear"

# The accessor variant of the existential operator ?. 
# can be used to soak up null references in a chain of properties. 
# Use it instead of the dot accessor . in cases where the base value may be null or undefined. 
# If all of the properties exist then you'll get the expected result, 
# if the chain is broken, undefined is returned instead of the TypeError that would be raised otherwise

zip = lottery.drawWinner?().address?.zipcode

# :: gives you quick access to an object's prototype;
# and super() is converted into a call against the immediate ancestor's method of the same name.
String::repeat = (n) ->
  Array(n + 1).join @

String::downcase = ->
  @toLowerCase()

String::upcase = ->
  @toUpperCase()

String::find = (str) ->
  @indexOf str

String::has = (str) ->
  (@indexOf str) > 0
  
String::dasherize = ->
  this.replace /_/g, "-"

# Destructuring Assignment
# it can be used for parallel assignment:

weatherReport = (location) ->
  # Make an Ajax request to fetch the weather...
  [location, 72, "Mostly Sunny"]

[city, temp, forecast] = weatherReport "Berkeley, CA"


# Destructuring assignment can be used with any depth of array and object nesting,
# to help pull out deeply nested properties.
futurists =
  sculptor: "Umberto Boccioni"
  painter:  "Vladimir Burliuk"
  poet:
    name:   "F.T. Marinetti"
    address: [
      "Via Roma 42R"
      "Bellagio, Italy 22021"
    ]

{poet: {name, address: [street, city]}} = futurists


# Destructuring assignment can even be combined with splats.
tag = "<impossible>"
[open, contents..., close] = tag.split("")


#   function Person(options) {
#    this.name = options.name, this.age = options.age, this.height = options.height;
#  }
class Person
  constructor: (options) -> 
    {@name, @age, @height} = options

Function binding

CoffeeScript -> 與 => 的差別

# => 用來this 是傳進來的東西時, callback 時會用到

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

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

try
  allHellBreaksLoose()
  catsAndDogsLivingTogether()
catch error
  print error
finally
  cleanUp()

cholesterol = 127

healthy = 200 > cholesterol > 60

html = """
       <strong>
         cup of coffeescript
       </strong>
       """

# /*
# SkinnyMochaHalfCaffScript Compiler v1.0
# Released under the MIT License
# */
###
SkinnyMochaHalfCaffScript Compiler v1.0
Released under the MIT License
###