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Amir Barylko Advanced Design Patterns
Beau%ful Javascriptwith Coffeescript
Amir Barylko
Amir Barylko Beautiful JS with CS
WHO AM I?
• Software quality expert
• Architect
• Developer
• Mentor
• Great cook
• The one who’s entertaining you for the next hour!
Amir Barylko Beautiful JS with CS
RESOURCES
• Email: [email protected]
• Twitter : @abarylko
• Blog: http://www.orthocoders.com
• Materials: http://www.orthocoders.com/presentations
Amir Barylko Beautiful JS with CS
COFFEESCRIPT
Amir Barylko Beautiful JS with CS
WHAT’S WRONG WITH JS
• Too verbose (too many { and } )
• Global Variables
• Lacks support for classes
• Hard to make inheritance
• Automatic type conversion between strings and numbers
• NaN is not a number, however it is a number
Amir Barylko Beautiful JS with CS
WHAT IS IT?
“CoffeeScript is a little language that compiles into JavaScript. Underneath all those awkward braces and semicolons, JavaScript has always had a gorgeous object model at its heart. CoffeeScript is an attempt to expose the good parts of JavaScript in a simple way.”
http://coffeescript.org/
Amir Barylko Beautiful JS with CS
STRING INTERPOLATION
•You can concatenate inside a double quote string using the “#” and “{ }”
"The result is #{3}" == "The result is 3"
•Or use any expression
"/movies/#{id}"
Amir Barylko Beautiful JS with CS
FUNCTIONS
•The arrow/lambda defines functionssquare = (x) -> x * x
•Parenthesis are optional when passing parameters storageDelete movieId, true
Amir Barylko Beautiful JS with CS
FUNCTIONS II
•Implicit return(the last expression is the return value)
•Multiple lines, indentation is importantdeleteMovie = (e) -> movieId = $(e.target).... storageDelete(movieId)
Amir Barylko Beautiful JS with CS
OBJECTS AS HASHES
•Declared using indentation
config = local: user: 'dev' pwd: 'dev123' remote: user: 'superdev' pwd: "impossibleToGuess"
Amir Barylko Beautiful JS with CS
ARRAYS
•Arrays are declared with “[ ]”
deploy = ['local', 'remote', 'uat']
fib = [1, 3, 5, 8, 13, 21]
•Slicing
first = fib[0..3]
noLast = fib[0..-2]
Amir Barylko Beautiful JS with CS
DESTRUCTURING ASSIGNMENT
•Multiple assignments
[firstName, nick, last] = ['D\'Arcy', 'Baconator', 'Lussier']
•Splat
reviews = [45, 29, 21, 10, 8, 4]
[best, secondBest, theRest...] = reviews
Amir Barylko Beautiful JS with CS
CONDITIONALS
•Classic if does not need parenthesisif isJson callIndex() display()else showMessage()
•Or use unless for the negated form
Amir Barylko Beautiful JS with CS
MODIFIERS
•The conditionals can be use as modifiers
callIndex() if isJson
exit() unless validated and inContext
Amir Barylko Beautiful JS with CS
SWITCH
• Selects between multiple conditions
movieReview = (critic, movie) -> switch critic when 'Jay' 'It Stinks!' when 'Darcy' if movie.match(/Bacon/) then... else throw new Error('Invalid critic name!')
Amir Barylko Beautiful JS with CS
LIST COMPREHENSION
•Iterate and call a function over each elementdeploy env for env in ['local', 'uat', 'prod']
•Or filter over a collectionnums = (num for num in [1..960] when isInteger(960 / num))
Amir Barylko Beautiful JS with CS
EXISTENTIAL OPERATOR
• Checks if a variable is null or undefined
question = paragraph? and not createdDate?
defaultValue ?= 5
precendence = first ? 5
• It can be used to avoid TypeError exceptionextension = secondaryAddress?().phone?.extension
Amir Barylko Beautiful JS with CS
CLASSES
class MovieRepository constructor: (@baseUrl) -> newMovie: -> $.ajax url: "#{@baseUrl}/movies/create" success: (data) -> $(id).append data
Amir Barylko Beautiful JS with CS
INHERITANCE
• One class can extend another
class Shape
constructor: (@width) ->
class Square extends Shape computeArea: -> Math.pow @width, 2
class Circle extends Shape radius: -> @width / 2 computeArea: -> Math.PI * Math.pow @radius(), 2
Amir Barylko Beautiful JS with CS
COMPLAINS(Go ahead, say it)
Amir Barylko Beautiful JS with CS
I ALREADY KNOW JS
•Continuous learning
•Benefits outweigh effort
•Generates way better code
•Do your duty as developer!
Amir Barylko Beautiful JS with CS
EXTRA COMPILATION STEP
•.NET and Java frameworks will do it for you
•Or tools will watch your folder and generate it for you
•Hardly notice the extra work
Amir Barylko Beautiful JS with CS
DEBUGGING IS HARD
•Same variable names
•Just set a breakpoint in the code
•and add watches, etc....
Amir Barylko Beautiful JS with CS
TESTING & 3RD PARTY
•Is just Javascript
•so use Jasmine
•or Qunit
•any other....
Amir Barylko Advanced Design Patterns
QUESTIONS?
Amir Barylko Beautiful JS with CS
RESOURCES
• Email: [email protected], @abarylko
• Slides & Source: http://www.orthocoders.com/presentations
• http://coffeescript.org
• https://github.com/sleepyfox/coffeescript-koans
• http://pivotal.github.com/jasmine/
• http://qunitjs.com/
• http://nodejs.org/
Amir Barylko Beautiful JS with CS
RESOURCES II