Node.js Stream writable.destroy() Method

The writable.destroy() method is an inbuilt application programming interface of Stream module which is used to destroy the created stream and you cannot call the write() method to write data again after you have already destroyed the created stream.

Syntax:

writable.destroy()

Parameters:

This method does not accept any parameters.

Return Value:

It returns all the properties of the Writable in which destroyed property is set to true. Below examples illustrate the use of writable.destroy() method in Node.js:

Example 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();

Output:

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 }

So, the created stream is destroyed.

Example 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('');

Output:

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)

In the above example, an error occurs because the write() method was called after the stream was destroyed.

Reference:

nidhi1352singh

Follow

Improve

Article Tags :

• Web Technologies
• Node.js
• Node.js-Stream-module