提示参数
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小牛编辑
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2023-12-01
问题
你的函数将会被可变数量的参数所调用。
解决方案
使用 splat 。
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"] } }
使用尾部参数:
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
通过在函数其中的(不多于)一个参数之后添加一个省略号(...),CoffeeScript 能把所有不被其他命名参数采用的参数值整合进一个列表中。就算并没有提供命名参数,它也会制造一个空列表。