javascript - #9 挑战 - 了解您的 Node (异步回调)

Question

我正在努力应对这个特殊的挑战:

练习 9 - 杂耍异步

You must collect the complete content provided to you by each of the URLs and print it to the console (stdout). You don't need to print out the length, just the data as a String; one line per URL. The catch is that you must print them out in the same order as the URLs are provided to you as command-line arguments.

这是我的代码:

var http = require('http');
var bl = require('bl')
var results = [];
var count = 0

function getURLs() {
  var urls = []
  for(var i = 2; i < process.argv.length; i++){
    urls.push(process.argv[i]);
  }
  return urls
}

function getHTTP(url){
  http.get(url, function(response){
    response.pipe(bl(function(err,data){
      if(err){return console.error(err)}
      results[count] = data.toString();
      count ++;
      if (count === process.argv.length - 2){
        printAll()
      }
    }))
  })
}

function printAll(){
  for(var i = 0 ; i < results.length; i++){
    console.log(results[i])
  }
}

function start(){
  retrivedURL = getURLs()
  for(var i = 0; i < retrivedURL.length; i++){
    getHTTP(retrivedURL[i])
  }
}

start()

我似乎不知道哪里出了问题——它是按照检索到的 URL 的顺序输出的。

Answer 1

您可以使用 async.eachSeries 来实现此目的，即使此 URL 调用异步。解释得很好here 。