Append data to a File using Node FS - Tutorial Kart

Append data to a File using Node FS

Node.js Append to a File

To append data to file in Node.js, use Node FS appendFile() function for asynchronous file operation or Node

FS appendFileSync() function for synchronous file operation.

In this Node.js Tutorial, we shall learn

Syntax of appendFile() function

Syntax of appendFileSync() function

Example for appendFile() : Appending data to file Asynchronously

Example for appendFileSync() : Appending data to file Synchronously

Syntax of appendFile()

fs.appendFile(filepath, data, options, callback_function);

Callback function is mandatory and is called when appending data to file is completed.

Syntax of appendFileSync()

fs.appendFileSync(filepath, data, options);

where :

filepath [mandatory] is a String that specifies file path

data [mandatory] is what you append to the file

options [optional] to specify encoding/mode/flag

Note : If file specified does not exist, a new file is created with the name provided, and data is appended to the

file.

Example : Node.js Append data to file asynchronously using appendFile()

To append data to a file asynchronously in Node.js, use appendFile() function of Node FS as shown below :

nodejs-append-to-file-example.js

// Example Node.js

program to append

data to file

var fs = require('fs');

// Example Node.js program to append data to file

var data = "\nLearn

var fs =with

require('fs');

Node.js

the help

of well built Node.js

Tutorial.";

var data = "\nLearn Node.js with the help of well built Node.js Tutorial.";

// append data to file

fs.appendFile('sample.t

xt',data,

// append'utf8',

data to file

// callback function

fs.appendFile('sample.txt',data,

'utf8',

function(err) {

if //

(err)

throw function

err;

callback

// if no error

function(err) { is

console.log("Data

appended

to file

if (err)

throw err;

successfully.")

}); // if no error

console.log("Data is appended to file successfully.")

});

Terminal Output

arjun@arjunVPCEH26EN:~/nodejs$

node nodejs-appendto-file-example.js

Data

is appended to

arjun@arjun-VPCEH26EN:~/nodejs$

node nodejs-append-to-file-example.js

file successfully.

Data is appended to file successfully.

File before appending

Welcome to

.

Welcome to .

File after appending

Welcome to

.

Learn Node.js with the

help of well built

Node.js

WelcomeTutorial.

to .

Learn Node.js with the help of well built Node.js Tutorial.

Example : Node.js Append data to file synchronously using appendFileSyc()

To append data to a file synchronously in Node.js, use appendFileSync() function of Node FS as shown below

:

nodejs-append-to-file-example-2.js

// Example Node.js

program to append

data to file

var fs = require('fs');

// Example Node.js program to append data to file

var data = "\nLearn

var fs =with

require('fs');

Node.js

the help

of well built Node.js

Tutorial.";

var data = "\nLearn Node.js with the help of well built Node.js Tutorial.";

// append data to file

fs.appendFileSync('sam

ple.txt',data,

'utf8');

// append data

to file

console.log("Data is

fs.appendFileSync('sample.txt',data,

'utf8');

appended

to file

successfully.")

console.log("Data is appended to file successfully.")

Terminal Output

arjun@arjunVPCEH26EN:~/nodejs$

node nodejs-appendto-file-example-2.js

Data

is appended to

arjun@arjun-VPCEH26EN:~/nodejs$

node nodejs-append-to-file-example-2.js

file successfully.

Data is appended to file successfully.

File before appending

Welcome to

.

Welcome to .

File after appending

Welcome to

.

Learn Node.js with the

help of well built

Node.js

WelcomeTutorial.

to .

Learn Node.js with the help of well built Node.js Tutorial.

Conclusion :

In this tutorial ¨C Node.js Append to a File, we have learnt to append data to a file in Node.js, synchronously

and asynchronously using appendFileSync() and appendFile() functions of Node FS respectively with Example

Node.js programs.

Node.js

?

Node.js Tutorial

Get Started W ith Node.js

Get Started W ith Node.js

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Install Node.js Ubuntu Linux

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Install Node.js Windows

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Node.js - Basic Example

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Node.js - Command Line Arguments

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Node.js - Create a module

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Node.js - Add new functions to Module

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Node.js - Override functions of Module

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Node.js - Callback Function

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Node.js - forEach

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Node.js Buffer - Create, Write, Read

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Node.js - Convert JSON to Buffer

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Node.js - Insert Documents to MongoDB Collection

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Node.js Mongoose Tutorial

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Node.js Mongoose - Installation

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Node.js Mongoose - Insert Single Document to MongoDB

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Node.js Mongoose - Insert Multiple Documents to MongoDB

Node.js URL

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Node.js - Parse URL parameters

Node.js FS (File System)

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Node FS

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Node FS - Read a File

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Node FS - Create a File

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Node FS - Write to a File

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Node FS - Append to a File

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Node FS - Rename a File

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Node FS - Delete a File

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Node FS Extra - Copy a Folder

Node.js JSON

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Node.js Parse JSON

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Node.js Write JSON Object to File

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