CoffeeScript 속사본

6742 단어 CoffeeScript

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

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