📜  Node.js Stream writable.destroy() 方法

📅  最后修改于: 2022-05-13 01:56:47.450000             🧑  作者: Mango

Node.js Stream writable.destroy() 方法

writable.destroy() 方法是 Stream 模块内置的应用程序编程接口,用于销毁创建的流,在销毁创建的流后不能再调用 write() 方法写入数据。

句法:

writable.destroy()

参数:此方法不接受任何参数。

返回值:它返回可写的所有属性,其中destroyed属性设置为true。

下面的例子说明了 Node.js 中writable.cork() 方法的使用:

示例 1:

// Node.js program to demonstrate the     
// writable.uncork() method  
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();
  }
});
  
// Writing data
writable.write('hi');
  
// Again writing some data
writable.write('hello');
  
// Calling destroy function
writable.destroy();

输出:

hi
hello
Writable {  _writableState:
   WritableState {
     objectMode: false,     highWaterMark: 16384,
     finalCalled: false,
     needDrain: false,
     ending: false,
     ended: false,
     finished: false,
     destroyed: true,
     decodeStrings: true,
     defaultEncoding: 'utf8',
     length: 0,
     writing: false,
     corked: 0,
     sync: false,
     bufferProcessing: false,
     onwrite: [Function: bound onwrite],
     writecb: null,
     writelen: 0,
     bufferedRequest: null,
     lastBufferedRequest: null,
     pendingcb: 2,
     prefinished: false,
     errorEmitted: false,
     emitClose: true,
     autoDestroy: false,
     bufferedRequestCount: 0,
     corkedRequestsFree:
      { next: null,
        entry: null,
        finish: [Function: bound onCorkedFinish] } },
  writable: true,
  _write: [Function: write],
  domain: null,
  _events: [Object: null prototype] {},
  _eventsCount: 0,
  _maxListeners: undefined }

因此,创建的流被销毁。

示例 2:

// Node.js program to demonstrate the     
// writable.uncork() method  
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();
  }
});
  
// Writing data
writable.write('hi');
  
// Again writing some data
writable.write('hello');
  
// Calling destroy function
writable.destroy();
  
writable.write('');

输出:

hi
hello
Error [ERR_STREAM_DESTROYED]: Cannot call write after a stream was destro
yed
    at doWrite (_stream_writable.js:411:19)
    at writeOrBuffer (_stream_writable.js:399:5)
    at Writable.write (_stream_writable.js:299:11)
    at /home/runner/QuizzicalFluffyOperation/index.js:29:10
    at Script.runInContext (vm.js:133:20)
    at Object. (/run_dir/interp.js:156:20)
    at Module._compile (internal/modules/cjs/loader.js:778:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:789:
10)
    at Module.load (internal/modules/cjs/loader.js:653:32)

在上面的示例中,由于在销毁流之后调用了 write() 方法,因此发生错误。

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