我在理解CoffeeScript中的解构赋值时遇到了一些麻烦. documentation包含几个示例,这些示例似乎一起暗示在分配期间重命名对象可用于投影(即映射,转换,变换)源对象.

我试图将a = [{Id：1,名称：’Foo’},{Id：2,名称：’Bar’}]投影到b = [{x：1},{x：2}].我试过以下但没有成功;我明显误解了一些事情.任何人都可以解释这是否可能？

我的穷人试图不归[[x：1​​},{x：2}]

a = [ { Id: 1, Name: 'Foo' }, { Id: 2, Name: 'Bar' } ]

# Huh? This returns 1.
x = [ { Id } ] = a

# Boo! This returns [ { Id: 1, Name: 'Foo' }, { Id: 2, Name: 'Bar' } ] 
y = [ { x: Id } ] = a

# Boo! This returns [ { Id: 1, Name: 'Foo' }, { Id: 2, Name: 'Bar' } ]
z = [ { Id: x } ] = a

CoffeeScript的并行分配示例

theBait   = 1000
theSwitch = 0

[theBait, theSwitch] = [theSwitch, theBait]

我理解这个例子意味着可以重命名变量,在这种情况下用于执行交换.

CoffeeScript的任意嵌套示例

futurists =
  sculptor: "Umberto Boccioni"
  painter:  "Vladimir Burliuk"
  poet:
    name:   "F.T. Marinetti"
    address: [
      "Via Roma 42R"
      "Bellagio, Italy 22021"
    ]

{poet: {name, address: [street, city]}} = futurists

我理解这个例子是从任意对象定义一系列属性,包括将数组元素分配给变量.

更新：使用jh的解决方案来展平嵌套对象数组

a = [ 
  { Id: 0, Name: { First: 'George', Last: 'Clinton' } },
  { Id: 1, Name: { First: 'Bill', Last: 'Bush' } },
]

# The old way I was doing it.
old_way = _.map a, x ->
    { Id: id, Name: { First: first, Last: last } } = x
    { id, first, last }

# Using thejh's solution...
new_way = ({id, first, last} for {Id: id, Name: {First: first, Last: last}} in a)

console.log new_way

解决方法:

b =(对于{Id：x}中的{x})有效：

coffee> a = [ { Id: 1, Name: 'Foo' }, { Id: 2, Name: 'Bar' } ]
[ { Id: 1, Name: 'Foo' },
  { Id: 2, Name: 'Bar' } ]
coffee> b = ({x} for {Id: x} in a)
[ { x: 1 }, { x: 2 } ]
coffee>