📜  Node.js Stream readable.destroyed 属性

📅  最后修改于: 2022-05-13 01:56:52.697000             🧑  作者: Mango

Node.js Stream readable.destroyed 属性

readable.destroyed 属性是 Stream 模块的内置应用程序编程接口,用于检查 readable.destroy()函数是否被调用。

句法:

readable.destroyed

返回值:如果 readable.destroy() 方法被调用则返回 true,否则返回 false。

下面的示例说明了 Node.js 中readable.destroyed 属性的使用:

示例 1:

// Node.js program to demonstrate the     
// readable.destroyed Property  
  
// Include fs module
const fs = require("fs");
  
// Constructing readable stream
const readable = fs.createReadStream("input.txt");
  
// Instructions for reading data
readable.on('readable', () => {
  let chunk;
  
  // Using while loop and calling
  // read method with parameter
  while (null !== (chunk = readable.read())) {
  
    // Displaying the chunk
    console.log(`read: ${chunk}`);
  }
});
  
// Handling error event
readable.on('error', err => {
    console.log(err);
});
  
// Calling destroy method
// with parameter
readable.destroy('error');
  
// Displays that the stream is 
// destroyed
console.log("Stream destroyed");
  
// Calling readable.destroyed
// Property
readable.destroyed;

输出:

Stream destroyed
true
error

示例 2:

// Node.js program to demonstrate the     
// readable.destroyed Property  
  
// Include fs module
const fs = require("fs");
  
// Constructing readable stream
const readable = fs.createReadStream("input.txt");
  
// Instructions for reading data
readable.on('readable', () => {
  let chunk;
  
  // Using while loop and calling
  // read method with parameter
  while (null !== (chunk = readable.read())) {
  
    // Displaying the chunk
    console.log(`read: ${chunk}`);
  }
});
  
// Displays that the stream is 
// destroyed
console.log("Program completed!!");
  
// Calling readable.destroyed
// Property
readable.destroyed;

输出:

Program completed!!
false
read: hello

所以,这里 readable.destroy() 方法在 readable.destroyed 属性之前没有被调用,所以它返回 false。

参考: https://nodejs.org/api/stream.html#stream_readable_destroyed