Beutiful javascript with coffeescript

Amir Barylko Advanced Design Patterns

Beautiful Javascript with

Coffeescriptwith 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