当前位置: 首页 > 工具软件 > CoffeeScript > 使用案例 >

CoffeeScript系列教程(一)—概述

尉迟彬
2023-12-01

概述

CoffeeScript是一门编译到JavaScript的小巧语言。CoffeeScript尝试用简洁的方式展示JavaScript优秀的部分。创建者Jeremy Ashkenas戏称它是JavaScript 的不那么铺张的小兄弟。
CoffeeScript就是将代码一一对应编译到JavaScript,当然了它仅仅是编译到JavaScript,不会在编译过程中执行JavaScript代码的。
CoffeeScript语法简洁,类似Ruby。基本原则就是用更少的代码实现更多的功能。编译过后的代码执行速度只会跟我们用JavaScript编写的代码一样快或者更快,大家不用担心执行速度的问题。

简单DEMO(选自官方)

编译前:

# 赋值:
number   = 42
opposite = true

# 条件:
number = -42 if opposite

# 函数:
square = (x) -> x * x

# 数组:
list = [1, 2, 3, 4, 5]

# 对象:
math =
  root:   Math.sqrt
  square: square
  cube:   (x) -> x * square x

# Splats:
race = (winner, runners...) ->
  print winner, runners

# 存在性:
alert "I knew it!" if elvis?

# 数组 推导(comprehensions):
cubes = (math.cube num for num in list)

编译后:

var cubes, list, math, num, number, opposite, race, square,
  __slice = [].slice;

number = 42;

opposite = true;

if (opposite) {
  number = -42;
}

square = function(x) {
  return x * x;
};

list = [1, 2, 3, 4, 5];

math = {
  root: Math.sqrt,
  square: square,
  cube: function(x) {
    return x * square(x);
  }
};

race = function() {
  var runners, winner;
  winner = arguments[0], runners = 2 <= arguments.length ? __slice.call(arguments, 1) : [];
  return print(winner, runners);
};

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

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;
})();
 类似资料: