参数数组化 Splat Arguments

## 问题 Problem 你的函数被调用时会接收到个数不一的参数。 Your function will be called with a varying number of arguments. ## 方法 Solution 使用_参数列_。 Use _splats_. ~~~ loadTruck = (firstDibs, secondDibs, tooSlow...) -> truck: driversSeat: firstDibs passengerSeat: secondDibs trunkBed: tooSlow loadTruck("Amanda", "Joel") # => { truck: { driversSeat: "Amanda", passengerSeat: "Joel", trunkBed: [] } } loadTruck("Amanda", "Joel", "Bob", "Mary", "Phillip") # => { truck: { driversSeat: "Amanda", passengerSeat: "Joel", trunkBed: ["Bob", "Mary", "Phillip"] } } ~~~ 末尾有一个单独的参数： With a trailing argument: ~~~ loadTruck = (firstDibs, secondDibs, tooSlow..., leftAtHome) -> truck: driversSeat: firstDibs passengerSeat: secondDibs trunkBed: tooSlow taxi: passengerSeat: leftAtHome loadTruck("Amanda", "Joel", "Bob", "Mary", "Phillip", "Austin") # => { truck: { driversSeat: 'Amanda', passengerSeat: 'Joel', trunkBed: [ 'Bob', 'Mary', 'Phillip' ] }, taxi: { passengerSeat: 'Austin' } } loadTruck("Amanda") # => { truck: { driversSeat: "Amanda", passengerSeat: undefined, trunkBed: [] }, taxi: undefined } ~~~ ## 讨论 Discussion 通过给函数的参数（最多一个）后面添加一个省略号（`...`），CoffeeScript会把所有没有被其他具名参数捕获的参数值合并到一个列表中。就算有的具名参数都没有对应的值，CoffeeScript也会提供一个空的列表。 By adding an ellipsis (`...`) next to no more than one of a function’s arguments, CoffeeScript will combine all of the argument values not captured by other named arguments into a list. It will serve up an empty list even if some of the named arguments were not supplied.