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Node.js Writable Stream pipe Event

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The pipe event in a Writable Stream is emitted when the stream.pipe() method is being called on a readable stream by attaching this writable to its set of destinations. 

Syntax:

Event: 'pipe'

Return Value: If the pipe() method is being called then this event is emitted else it is not emitted. 

The below examples illustrate the use of the ‘pipe’ event in Node.js: 

Example 1: 

javascript




// Node.js program to demonstrate the   
// pipe event
 
// Accessing fs module
const fs = require("fs");
 
// Create a readable stream
const readable = fs.createReadStream('input.txt');
 
// Create a writable stream
const writable = fs.createWriteStream('output.txt');
 
// Handling pipe event
writable.on("pipe", readable => {
    console.log("Piped!");
});
 
// Calling pipe method
readable.pipe(writable);
 
console.log("Program Ended.");


Output:

Piped!
Program Ended.

Example 2: 

javascript




// Node.js program to demonstrate the   
// pipe event
 
// Accessing fs module
const fs = require("fs");
 
// Create a readable stream
const readable = fs.createReadStream('input.txt');
 
// Create a writable stream
const writable = fs.createWriteStream('output.txt');
 
// Handling pipe event
writable.on("pipe", readable => {
    console.log("Piped!");
});
 
console.log("Program Ended");


Output:

Program Ended

So, here pipe() function is not called so the pipe event is not emitted. 

Reference: https://nodejs.org/api/stream.html#stream_event_pipe



Last Updated : 30 Mar, 2023
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