Nodejs阻塞直到异步调用完成？

Question

如何让 nodejs 应用程序等待异步调用完成？

主咖啡：

hosts = require './suhosts'
dns = require 'dns'
async = require 'async'

data = {}
async.each hosts, (host, cb_e) ->
   dns.lookup host,  (err, address, family)-> data[host] = address
 , () ->
   console.log data

如果有人像coffee main.coffee 这样运行它，它将在工作之前退出。

Answer 1

您没有调用所需的async.each 回调。

data = {}
async.each hosts, (host, cb_e) ->
   dns.lookup host, (err, address, family) ->
      data[host] = address
      cb_e(err)
 , () ->
   console.log data