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我是 JavaScript 新手，尤其是 Node.js，我有 2 个要尝试执行的函数。一个从文件中获取数据并将其传递给一个列表，另一个从该列表中读取以从文本文件中获取其中一行。我的代码完美无缺，除了第二个函数在第一个函数之前执行，考虑到第二个函数需要第一个函数的信息才能成功执行，这显然是一个问题。

let names = [];

function loadNames() {
  var reader = new LineReader("names.txt");
  reader.on("line", function (line) {
  names.push(line);
  console.log("length " + names.length)
  });
}

function getName() {
  console.log(names.length);
    for (var i = 0; i < names.length; i++) {
      var name = names[i];
      console.log("Loaded - " + name);
 }
  console.log("what is wrong with this thing?")
}

加载名称() 获取名称()

预期输出：

length 1
length 2
length 3
length 4
length 5
length 6
length 7
length 8
length 9
length 10
10
Loaded - 1
Loaded - 2
Loaded - 3
Loaded - 4
Loaded - 5
Loaded - 6
Loaded - 7
Loaded - 8
Loaded - 9
Loaded - 10
what is wrong with this thing?

实际输出（除了括号中的所有内容）：

0 (from getName -> console.log(names.length))
what is wrong with this thing? (from getName)
length 1 (from loadNames -> console.log("length" + names.length))
length 2 (from loadNames -> console.log("length" + names.length))
length 3 (from loadNames -> console.log("length" + names.length))
length 4 (from loadNames -> console.log("length" + names.length))
length 5 (from loadNames -> console.log("length" + names.length))
length 6 (from loadNames -> console.log("length" + names.length))
length 7 (from loadNames -> console.log("length" + names.length))
length 8 (from loadNames -> console.log("length" + names.length))
length 9 (from loadNames -> console.log("length" + names.length))
length 10 (from loadNames -> console.log("length" + names.length))
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1 回答 1

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网络上有很多很好的资源来理解 JavaScript 的异步特性。

对于您的特定问题，我认为您正在使用的库提供了解决方案。

reader.on('end', function () {
    getName()
}
于 2017-12-06T01:59:30.737 回答