In loving memory of CoffeeScript

a lot is in es6

Bound functions

var square = (x)=> x + x

Default params

var fill = (container, liquid="coffee")=> {
  console.log("Filling the #{container} with #{liquid}...")
}

Destructuring assignment

[a, b] = [1, 2]
{a, b} = {a:1, b:2}
{ AppStore } = App.Stores

Classes

class Animal {
  constructor(name) {
    this.name = name;
  }
  move(meters) {
    this.distance += meters;
  }
}
class Snake extends Animal {
  move() {
    alert("Slithering...");
    super(5);
  }
}

Classes

class Animal
  constructor: (@name)->
  
  
  move: (meters)->
    @distance += meters
    
    
class Snake extends Animal
  move: ->
    alert "Slithering..."
    super 5
    
    

Rest params

store.add = (category, ...items)=> {
  items.forEach((item)=> {
    store.aisle[category].push(item);
  });
};

Rest params

store.add = (category, items...)->
  items.forEach (item)->
    store.aisle[category].push item
    
    

Template strings

var hello = (name)=> `hello ${name}`
var multiline = ()=> {
 return `a
b
c`;
}

Template strings

hello = (name)=> "hello #{name}"
multiline = ->
  """
  a
  b
  c
  """
  

No var

myVariable = 'myValue'

# never miss a var
# hoisting
# private by default
# JSLint compliant

Significant whitespace

if (url) {
  fetch(url, (data)=> {
    console.log(data);
  });
}
else {
  nope();
}

data = {
  url: '/api/data.json',
  properties: ['a','b'],
  params: {
    query: 'Ma'
  }
};

Significant whitespace

if url
  fetch url, (data)->
    console.log data
else
  nope()
  
  
  
  
data =
  url: '/api/data.json'
  properties: ['a','b']
  params:
    query: 'Ma'
    
    

Simple loops

words = 'Peter Piper picked a peck'.split ' '

for word, index in words
  console.log "#{index} #{word}"
  
  

Simple loops

var words = 'Peter Piper picked a peck'.split(' ');

for (var index = 0, len = words.length; index < len; index++) {
  var word = words[index];
  console.log("#{index} #{word}");
}

Simple loops

options =
  strict: true
  magic: 'string'
  
  
for key, value of options
  console.log "#{key} #{value}"
  
  

Simple loops

var options = {
  strict: true,
  magic: 'string'
};

for (key in options) {
  var value = options[key];
  console.log(key + " " + value);
}

Automatic returns

singHappy = ->
  if happy
    clapAlong()
  else
    dont()

Everything is an expression

# each
for word in words
  console.log "#{prefix} #{word}"
  
# map
prefixed = for word in words
  "#{prefix} #{word}"
  
# map + filter
fWords = for word in words when word[0] == 'f'
  "#{prefix} #{word}"
  

Everything is an expression

greeting = switch day
  when 'monday' then 'piss off'
  when 'sunday' then 'how do you do'
  else 'hello'
  
getGreeting = (day)->
  switch day
    when 'monday' then 'piss off'
    when 'sunday' then 'how do you do'
    else 'hello'

Conditionals

request() if active

return unless options?

Aliases / operators

== -> ===
&& -> and
|| -> or
? : ; -> if then else
if ! -> unless
(start < date && date < end) -> (start < date < end)
this. -> @
.prototype. -> ::

if myVariable? // not null or undefined
if params?.query? // soak operator

End of life?

• JS
  Coffee
  JSNext

Thanks

@markbrown4