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Node.js Articles
Page 6 of 22
Determining the User IP Address in Node
Node.js is a completely open source technology that runs on JavaScript runtime environment. When the users want to access a website or link, they connect with the link using their system IP. We can use the dns.lookup() method in Node to find the IP address of the current user.Syntaxdns.lookup(hostname, [options], callback)ParametersThe parameters are described below −hostname − This input parameter consists of the web link which is valid or active.options − Default is 0. It takes input for the IP type, i.e., 4 for Ipv4 and 6 for Ipv6.callback − Handles any error if it occursExample 1Create a file with ...
Read MoreNode.js – hash.digest() Method
The Hash class is one of the many utility classes that is used for creating the hash digests of data. The hash.digest() method calculates all the data that needs to be hashed passed inside the hash function and returns them. If an encoding is defined, a string will be returned, else a buffer is returned.Syntaxhash.digest([encoding])ParametersIt takes a single parameter −encoding − This input parameter takes input for the encoding to be applied while calculating the hash.Example 1Create a file with the name "hashDigest.js" and copy the following code snippet. After creating the file, use the command "node hashDigest.js" to run ...
Read MoreTiming features in Node.js
The timer module in Node.js consists of different functions that can control and alter the timings of code execution. In this article, we will see how to use some of these functions.setTimeout() MethodThe setTimeout() method schedules the code execution after a designated amount of milliseconds. Only after the timeout has occurred, the code will be executed. The specified function will be executed only once. This method returns an ID that can be used in clearTimeout() method.SyntaxsetTimeout(function, delay, [args])ParametersThe parameters are defined below:function − This parameter takes input for the function that will be executed.delay − This is the time duration after which ...
Read MoreNode.js – util.inspect() method
The util.inspect() method returns the string representation of the objects that are intended for the debugging process.Syntaxutil.inspect(object, [showHidden], [depth], [colors])ParametersThe parameters are defined as below:object − A JavaScript primitive type or an object is given as input.optionsshowHidden − This is set as false by default. If true, this option includes the non-enumerable symbols and properties that are included in the formatted result. WeakMap and WeakSet are also included.depth − It specifies the number of recursions to be applied while formatting objects.colors − The output is set styled with ANSI color codes if this value is set to true. Colors passed are customizable.customInspect − The ...
Read MoreNode.js – util.inherits() Method
The util.inherits() method basically inherits the methods from one construct to another. This prototype will be set to a new object to that from the superConstructor.By doing this, we can mainly add some validations to the top of Object.setPrototypeOf(constructor.prototype, superConstructor.prototype).Syntaxutil.inherits(constructor, superConstructor)ParametersThe parameters are described below -constructor − This is a function type input that holds the prototype for constructor the user wants to be inherited.superConstructor − This is the function that will be used for adding and validating the input validations.Example 1Create a file "inherits.js" and copy the following code snippet. After creating the file, use the command "node inherits.js" to run ...
Read MoreNode.js – util.debuglog() Method
The util.debuglog() method creates a function that can be used to write the desired error/debug messages to stderr. These error messages are written only upon the existence of the NODE_DEBUG environment variable.Syntaxutil.debuglog(section, [callback])ParametersThe parameters are described below −section − This parameter takes the portion of the application for which the debug log is being created.callback − This is the callback function which will receive the pointer if any error occurs during the execution of method.Example 1Create a file with the name "debuglog.js" and copy the following code snippet -// util.debuglog() demo example // Importing the util module const util ...
Read MoreHow to read and write JSON file using Node?
Node.js provides powerful tools for working with files, including reading and writing JSON files. JSON (JavaScript Object Notation) is widely used for storing and exchanging data in applications. This article walks you through reading and writing JSON files in Node.js with examples. Approaches to Read JSON file Using fs.readFileSync (Synchronous) Using fs.readFile (Asynchronous) JSON File data.json { "name": "PankajBind", "age": 21, "skills": ["JavaScript", "Node.js", "React"] } Using fs.readFileSync (Synchronous) The fs module in Node.js provides methods to interact with the file ...
Read MoreHow to use Class in Node?
Introduction Node.js is trending as an environment where different efficient and logical applications are executed at the moment. One of them is extending modern JS syntax, for example, classes, which makes OOP in Node.js more possible to use and improve. Scroll down to learn what a class is in Node.js, how one can be defined, how methods can/must be added, subclass/superclass in Node.js, and some uses of classes in Node.js. What is a Class in Node.js? A class is a blueprint of objects that have certain characteristics and behaviors or actions. Classes were introduced in ECMAScript 2015 ( ES6) as ...
Read MoreHow to update Node.js and NPM to the latest version?
Having the latest Node.js and NPM is crucial as developers get to have access to the new features, security fixes, and improved performance. In those tools, you need to learn the following general steps in order to update them quickly This is the simplest guide to update those two tools. Why Update Node.js and NPM? Here are some reasons why you should update Node.js and NPM − Access New Features: Every one or two updates, new features and improvements make their ways into the software. Improved Security: Updates patch and other vulnerabilities in the environment so as to remove ...
Read MoreHow to use an ES6 import in Node.js?
Since ES6, JavaScript has a standardized way in terms of using the import statement in your project to include modules. Originally Node.js was using require() to import a module but with the update it is also imported ES6 import. This article will explain how to use ES6 import in Node.js, why it is important, and what constitutes good practice. Why Use ES6 Imports in Node.js? The following are some key reasons why you should use ES6 imports in Node.js − Modern Syntax: import is even better than require() to import modules because it is clean ...
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