在 node 中.js如何检查特定的写入流是否已打开

Question

在打开流之前需要检查流是否已经打开

var fs=require('fs');
var stream=fs.createWriteStream(filePath, {flags: 'a'});
stream.on('open',function(){

});

Answer 1

流

在打开时会发出open，因为这是异步的，所以无法知道它什么时候会发出，你甚至可以写一些类似的东西

var _path = "text.txt";
var stream1 = fs.createWriteStream(_path,{flags:"a"});
var stream2 = fs.createWriteStream(_path,{flags:"a"});
var stream3 = fs.createWriteStream(_path,{flags:"a"});
var streamN = fs.createWriteStream(_path,{flags:"a"});

当准备就绪时，所有人都会发出open事件。

如果在发出 Open 时转储console.log其中一个对象，您将看到一个具有许多属性的对象，例如保留写入状态的_writableState。

一种不太棒的方法是尝试如下所示的内容

var _path = "text.txt";
var stream = fs.createWriteStream(_path,{flags:"a"});
var stream2 = fs.createWriteStream(_path,{flags:"a"});
var lock = false; // try switching this , when opened and on other events to get the flow.