CoffeeScript for循环无法执行多个操作？

Question

第一个与第二个不同的是什么？第一个按预期工作，但第二个没有达到我期望的水平。在第一个中，我通过callToPhotos间接打电话，但在第二个中，我直接打电话给getPhotos，并通过相册。 为什么以及这有什么不同？

$.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

它与第二片段的循环变量范围有关。您可以引入一个立即调用函数（IIF）来解决这个问题（在http://coffeescript.org/#loops部分= d的底部阅读有关do关键字）：

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

我建议你虽然使用第一种方法，因为它是与IIF相同，但我认为更清楚，因为额外功能现在具有描述性变量名称;也许声明getPhotos函数内部的功能：

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，在这两种情况下，我加入空return，使得它不生成并返回一个数组理解作为其最后一个表达式= P）