How to Create and Modify Properties File Form Java Program in Text and XML Format?

JavaScript Program to read text File

Last Updated : 10 Jan, 2025

Given a text file, write a JavaScript program to extract the contents of that file. There is a built-in Module or in-built library in NodeJs that handles all the reading operations called fs (File-System). It is basically a JavaScript program (fs.js) where a function for reading operations is written. Import fs-module in the program and use functions to read text from the files in the system.

Pre-requisites:

How to import a library in JavaScript. Read from here: JavaScript | Importing and Exporting Modules.

Syntax:

readFile( Path, Options, Callback);

Parameters:

path: It takes in relative path from the program to the text File. If both file and program are in the same folder, then simply give the file name of the text file.
Options: It is an optional parameter that specifies the data is to be read from the file. If nothing is passed, then the default raw buffer is returned.
Callback Function: It is the callback function that has further two arguments (err, data). If the operation fails to extract the data, the error shows what is the fault, and else data argument will contain the data from the file.

Example: Suppose there is a file with the name Input.txt in the same folder as the JavaScript program.

javascript

// Requiring fs module in which 
// readFile function is defined.
const fs = require('fs');

fs.readFile('Input.txt', (err, data) => {
  if (err) throw err;

  console.log(data.toString());
});

Example: In this example, we are creating Instead of converting buffer into text using the tostring function, directly get the data into text format also.

HTML

<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, 
                 initial-scale=1.0">
    <title>Read File in Browser</title>
</head>

<body>
    <input type="file" id="fileInput" />
    <script>
        document.getElementById('fileInput')
            .addEventListener('change', (event) => {
                const file = event.target.files[0];
                const reader = new FileReader();

                reader.onload = function () {
                    const content = reader.result;
                    console.log(content);
                };

                reader.onerror = function () {
                    console.error('Error reading the file');
                };

                reader.readAsText(file, 'utf-8');
            });
    </script>
</body>

</html>

Output:

This is some data inside file Input.txt.

Note: To run the script first make both files in the same folder and then run script.js using NodeJs interpreter in terminal.

How to Create and Modify Properties File Form Java Program in Text and XML Format?

imdhruvgupta

Improve

Article Tags :

Similar Reads

How to read a local text file using JavaScript?

Reading a local text file involves accessing the contents of a file stored on a user's device. Using JavaScript, this can be achieved with the HTML5 File API and the FileReader object, which reads files selected through an <input> element or drag-and-drop, asynchronously. Getting Started with

How to read large text files in Python?

In this article, we will try to understand how to read a large text file using the fastest way, with less memory usage using Python.Â To read large text files in Python, we can use the file object as an iterator to iterate over the file and perform the required task. Since the iterator just iterates

Reading and Writing to text files in Python

Python provides built-in functions for creating, writing, and reading files. Two types of files can be handled in Python, normal text files and binary files (written in binary language, 0s, and 1s). Text files: In this type of file, Each line of text is terminated with a special character called EOL

How to load the contents of a text file into a JavaScript variable?

In this article, we will examine how to read the contents of any text file that exists on your computer into a variable using JavaScript. The following are a few basic pointers that everybody should brush through before looking at the code: Event listeners: These are predefined functions that exist

How to Create and Modify Properties File Form Java Program in Text and XML Format?

Properties file are a text-oriented key value a pair of contents present in a Java project with .properties extension. Line by line, the key-value pair of contents are present, and they are usually prepared by means of notepad, Wordpad, EditPlus, etc., Properties files are usually helpful to store i

Take input from user and store in .txt file in Python

In this article, we will see how to take input from users and store it in a .txt file in Python. To do this we will use python open() function to open any file and store data in the file, we put all the code in Python try-except block. Let's see the implementation below. Stepwise ImplementationÂ Ste

Ways to Read Input from Console in Java

In Java, there are four different ways to read input from the user in the command line environment(console). 1. Using Buffered Reader ClassBuffered Reader Class is the classical method to take input, Introduced in JDK 1.0. This method is used by wrapping the System.in (standard input stream) in an I

Node.js filehandle.read() Method

The filehandle.read() method reads the file using a file descriptor. In order to read files without file descriptors the readFile() method of the filehandle package can be used. Node.js is used for server-side scripting. Reading and writing files are the two most important operations that are perfor

How to read a Large File Line by Line in PHP ?

We will use some file operations to read a large file line by line and display it. Read a file: We will read the file by using fopen() function. This function is used to read and open a file. Syntax: fopen("filename", access_mode); Parameter: filename: Filename is the name of the file access_mode: I

File opening modes(r versus r+)

A file has to be opened before the beginning of reading and writing operations. Opening a file creates a link between the operating system and the file function. Syntax for opening a file: FILE *fp; fp = fopen( " filename with extension ", " mode " ); Opening of file in detail: FILE: structure defin