CoffeeScript 速抄本
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CoffeeScript 速抄本
foucsj 发表于3年前
CoffeeScript 速抄本
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摘要: 第一次见到Coffee时,活生生的被它风骚的语法迷惑,让当时正在写c#的我感到了无地自容。遂消费一晚上的时间整理了一份CoffeeScript快速抄袭手册。

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
标签: CoffeeScript
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