CoffeeScript for循環無法執行多個操作？

Question

第一個與第二個不同的是什麼？第一個按預期工作，但第二個沒有達到我期望的水平。在第一個中，我通過callToPhotos間接打電話，但在第二個中，我直接打電話給getPhotos，並通過相冊。 爲什麼以及這有什麼不同？

$.ajax 
    method:'get' 
    url: '/slides/facebook-albums' 
    success: (albums) -> 
     renderAlbums(albums) 
     callToPhotos(albums) 

renderAlbums = (albums) -> 
    for album in albums 
     $('#facebook .main').append("<div id='#{ album['id'] }' class='album-info'><a class='#{album['id']} fb-album' href='#'>#{album['name']}</a> 
     <img src=#{album['cover_photo']} width='100' height= '100' class='#{album['id']} fb-album'></div>") 

callToPhotos = (albums) -> 
    for album in albums 
     getPhotos(album) 

getPhotos = (album) -> 
     $.ajax 
     method: "get" 
     url: "/slides/#{album['id']}/photos" 
     success: (photos) -> 
      renderPhotos(photos, album['id']) 

-

$.ajax 
    method:'get' 
    url: '/slides/facebook-albums' 
    success: (albums) -> 
     renderAlbums(albums) 
     # callToPhotos(albums) 
     getPhotos(albums) 

renderAlbums = (albums) -> 
    for album in albums 
     $('#facebook .main').append("<div id='#{ album['id'] }' class='album-info'><a class='#{album['id']} fb-album' href='#'>#{album['name']}</a> 
     <img src=#{album['cover_photo']} width='100' height= '100' class='#{album['id']} fb-album'></div>") 

callToPhotos = (albums) -> 
    for album in albums 
     getPhotos(album) 

getPhotos = (albums) -> 
    for album in albums 
     $.ajax 
     method: "get" 
     url: "/slides/#{album['id']}/photos" 
     success: (photos) -> 
      renderPhotos(photos, album['id']) 

Answer 1

它與第二片段的循環變量範圍有關。您可以引入一個立即調用函數（IIF）來解決這個問題（在http://coffeescript.org/#loops部分= d的底部閱讀有關do關鍵字）：

getPhotos = (albums) -> 
    for album in albums 
    do (album) -> 
     $.ajax 
     method: "get" 
     url: "/slides/#{album['id']}/photos" 
     success: (photos) -> 
      renderPhotos(photos, album['id']) 
    return 

我建議你雖然使用第一種方法，因爲它是與IIF相同，但我認爲更清楚，因爲額外功能現在具有描述性變量名稱;也許聲明getPhotos函數內部的功能：

getPhotos = (albums) -> 
    getAlbum = (album) -> 
    $.ajax 
     method: "get" 
     url: "/slides/#{album['id']}/photos" 
     success: (photos) -> 
     renderPhotos(photos, album['id']) 

    getAlbum album for album in albums 

    return 

（注意，在這兩種情況下，我加入空return，使得它不生成並返回一個數組理解作爲其最後一個表達式= P）