javascript - 循环结束后如何发送函数结果？

Question

在 CoffeeScript 的 Node/Express 服务器中，我有以下功能:

@resolveServers = (url, servers, answer) ->
  result = []
  treatServer(url, server, (treatAnswer) ->
    result.push(treatAnswer)
  ) for server in servers
  answer(result)

treatServer 方法需要一些时间，并且在循环完成之前发送答案。如何仅在循环结束时发送结果？

感谢您的帮助。

Answer 1

只要你事先知道服务器的数量，这很容易:

@resolveServers = (url, servers, answer) ->
    result = []
    count = 0
    treatServer(url, server, (treatAnswer) ->
        result.push(treatAnswer)
        count++
        answer result if count is servers.length
    ) for server in servers

编辑:再想一想。对于您的情况，这可以更容易地解决:

@resolveServers = (url, servers, answer) ->
    result = []
    treatServer(url, server, (treatAnswer) ->
        result.push treatAnswer
        answer result if result.length is servers.length
    ) for server in servers

编辑 2: 为 squint指出，push 返回数组的长度:

@resolveServers = (url, servers, answer) ->
    result = []
    treatServer(url, server, (treatAnswer) ->
        answer result if result.push(treatAnswer) is servers.length
    ) for server in servers

如果您想保持代码的可读性，最后一次编辑可能不是最佳选择;-)