CoffeeScript是逐句编译为JavaScript的一种小型语言，且没有运行时的解释器。 作为JavaScript的替代品之一，CoffeeScript旨在编译人类可读、美观优雅且速度不输原生的代码， 且编译后的代码可以在任何JavaScript运行时正确运行。

参阅 CoffeeScript官方网站以获取CoffeeScript的完整教程。

CoffeeScript是一种很潮的编程语言，它紧随众多现代编程语言的趋势。 因此正如Ruby和Python，CoffeeScript使用井号标记注释。

# 这是注释

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大段落注释以此为例，可以被直接编译为 '/ *' 和 '* /' 包裹的JavaScript代码。

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在继续之前你需要了解JavaScript的基本概念。

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示例中 => 后为编译后的JavaScript代码

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赋值

number   = 42 #=> var number = 42;

opposite = true #=> var opposite = true;

条件

number = -42 if opposite #=> if(opposite) { number = -42; }

函数

square = (x) -> x * x #=> var square = function(x) { return x * x; }

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fill = (container, liquid = "coffee") ->

  "Filling the #{container} with #{liquid}..."

#=>var fill;

#

#fill = function(container, liquid) {

#  if (liquid == null) {

#    liquid = "coffee";

#  }

#  return "Filling the " + container + " with " + liquid + "...";

#};

区间

list = [1..5] #=> var list = [1, 2, 3, 4, 5];

对象

math =

  root:   Math.sqrt

  square: square

  cube:   (x) -> x * square x

#=> var math = {

#  "root": Math.sqrt,

#  "square": square,

#  "cube": function(x) { return x * square(x); }

#}

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Splats

race = (winner, runners...) ->

  print winner, runners

#=>race = function() {

#  var runners, winner;

#  winner = arguments[0], runners = 2 <= arguments.length ? __slice.call(arguments, 1) : [];

#  return print(winner, runners);

#};

存在判断

alert "I knew it!" if elvis?

#=> if(typeof elvis !== "undefined" && elvis !== null) { alert("I knew it!"); }

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数组推导

cubes = (math.cube num for num in list) 

#=>cubes = (function() {

#   var _i, _len, _results;

#   _results = [];

#   for (_i = 0, _len = list.length; _i < _len; _i++) {

#       num = list[_i];

#       _results.push(math.cube(num));

#   }

#   return _results;

#  })();

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foods = ['broccoli', 'spinach', 'chocolate']

eat food for food in foods when food isnt 'chocolate'

#=>foods = ['broccoli', 'spinach', 'chocolate'];

#

#for (_k = 0, _len2 = foods.length; _k < _len2; _k++) {

#  food = foods[_k];

#  if (food !== 'chocolate') {

#    eat(food);

#  }

#}

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