获取Coffeescript在FOR循环中创建一个局部变量 [英] Getting Coffeescript to create a local variable in a FOR loop

问题描述

如何获得 dealViewItem 进入FOR循环的范围？目前，dealViewItem在其外部作用域，所有我的事件侦听器都被添加到最后一个dealViewItem。

How can I get dealViewItem into the scope of the FOR loop? Currently, dealViewItem is scoped outside of it, and all my event listeners are added to the last dealViewItem.

  for deal in dealArray
        dealViewItem = dealViewFactory.DealDetail(deal)
        dealViewItem.addEventListener 'click', ->
          dealCart.push(deal.dealId)
          dealViewItem.setAddedToCart()
          btnTakeDeals.setEnabled = true
        dealHolder.add(dealViewItem)

推荐答案

这是 do 。它将立即运行一个函数，任何与参数之一具有相同名称的局部变量将被传递给它，以确保适当的关闭范围。

this is what the do keyword is for. It will run a function immediately and any local variables with the same name as one of the arguments will be passed into it, ensuring proper closure scope.

for deal in dealArray
  do (deal) ->
    dealViewItem = dealViewFactory.DealDetail(deal)
    dealViewItem.addEventListener 'click', ->
      dealCart.push(deal.dealId)
      dealViewItem.setAddedToCart()
      btnTakeDeals.setEnabled = true
    dealHolder.add(dealViewItem)

查看编译版本

do 在循环之外使用自执行功能。

do can also be used outside of loops for self executing functions.

#coffeescript
do ->
  foo = 'bar'

// javascript
(function() {
  var foo;
  return foo = bar;
})();

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