Node.js Stream writable.writableLength 属性

writable.writableLength 属性是流模块的内置应用程序，用于检查队列中准备写入的字节数。

句法：

writable.writableLength

返回值：此属性返回准备写入队列的字节数。

下面的例子说明了 Node.js 中writable.writableLength 属性的使用：

示例 1：

// Node.js program to demonstrate the     
// writable.writableLength Property
  
// Accessing stream module
const stream = require('stream');
  
// Creating a stream and creating 
// a write function
const writable = new stream.Writable({
  
  // Write function with its 
  // parameters
  write: function(chunk, encoding, next) {
  
    // Converting the chunk of
    // data to string
    console.log(chunk.toString());
    next();
  }
});
  
// Calling cork() function
writable.cork();
  
 //Writing data
writable.write('hi');
  
// Again writing some data
writable.write('GFG');
  
// Calling writable.writableLength 
// Property
writable.writableLength;

输出：

5

示例 2：

// Node.js program to demonstrate the     
// writable.writableLength Property
  
// Accessing stream module
const stream = require('stream');
  
// Creating a stream and creating 
// a write function
const writable = new stream.Writable({
  
  // Write function with its 
  // parameters
  write: function(chunk, encoding, next) {
  
    // Converting the chunk of
    // data to string
    console.log(chunk.toString());
    next();
  }
});
  
// Calling cork() function
writable.cork();
  
 //Writing data
writable.write('hi');
  
// Calling uncork() function
writable.uncork();
  
// Again calling cork function
writable.cork();
  
// Again writing some data
writable.write('GFG');
  
// Calling writable.writableLength 
// Property
writable.writableLength;

输出：

hi
3

在这里，缓冲区中不再存在数据“hi”因此，缓冲区只有 3 个字节存在数据“GFG”占用 3 个字节。

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