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Node.js Articles
Page 16 of 22
Node.js – util.isDeepStrictEqual() Method
The util.isDeepStrictEqual() method as the name suggests, is used for checking whether the two values are deep strict equal or not. If both the values are deep strict equal, true is returned else it returns false.Syntaxutil.isDeepStrictEqual(val1, val2)Parametersval1 & val2 – Both the input parameters can accept class, function, object or a JavaScript primitive value. The above function checks the equality between these two values.Example 1Create a file with the name "deepStrictEqual.js" and copy the following code snippet. After creating the file, use the command "node deepStrictEqual.js" to run this code.// util.isDeepStrictEqual() Demo Example // Importing the util module const util = require('util'); ...
Read MoreNode.js – util.types.isBoxedPrimitive() Method
The util.types.isBoxedPrimitive() method checks whether the passed value is a built-in Primitive object or not. If the above condition is satisfied, it returns True, else False. Primitive object includes new Boolean(), new String() or Object(Symbol()).Syntaxutil.types.isBoxedPrimitive(value)Parametersvalue − This input value takes input for the required parameter and checks if it's a Float32-Array instance or not.It returns True or False based upon the input value passed.Example 1Create a file with the name "isBoxedPrimitive.js" and copy the following code snippet. After creating the file, use the command "node isBoxedPrimitive.js" to run this code.// util.types.isBoxedPrimitive() Demo Example // Importing the util module const util ...
Read MoreNode.js – util.callbackify() Method
The util.callbackify() method takes an async function as a parameter (or a function with Promise) and returns a function with the callback style. The callback will hold the rejection reason as the first parameter (or null in case of Promise) and the resolved value as the second parameter.Syntaxutil.callbackify(function)Parametersfunction − The input parameter for the async_function required for callback.Example 1Create a file "callbackify.js" and copy the following code snippet. After creating the file, use the command "node callbackify.js" to run this code.// util.callbackify() demo example // Importing the util module const util = require('util'); // Defining a simple async function ...
Read MoreNode.js – hash.copy() Method
The Hash class is one of the many utility classes that is used for creating the hash digests of data. The hash.copy() method creates a new Hash object that will contain a deep copy of the internal state of the current hash object.Syntaxhash.copy([options])Parametersoptions −This input parameter takes input to control the stream behaviour and therefore will contain the stream.tranformOptions.Example 1Create a file "hashCopy.js" and copy the following code snippet. After creating the file, use the command "node hashCopy.js" to run this code.// hash.update() demo Example // Importing the crypto module const crypto = require('crypto'); // Defining the hash ...
Read MoreHow to Install Newman using NPM?
We can install Newman using npm. Newman can be installed using npm and Node.js. To download Node.js, navigate to the link − https://nodejs.org/en/download/current/.As we have downloaded Node.js successfully, we can check it with the below command −In Windowsnode --vIn Linuxnode --versionThe npm package becomes available automatically on installing Node.js. We can check it with the below command −In Windowsnpm --vIn Linuxnpm --versionFinally to install Newman, run the below command −For Windowsnewman --vFor Linuxnewman --version
Read MoreDifference between NodeJS and ReactJS
ReactJS and NodeJS both are a widely used subsets of JavaScript nowadays with high performance. But both are different in someways. In the below article, we will discuss the difference between the two and which is better to use to build a web application and why ?NodeJSIt is a completely open-source and cross-platform runtime environment used for executing JavaScript code outside of a browser.The event driven model of NodeJs lets the user to create a fast and scalable network applications. First thing to remember about NodeJS is that its neither a framework and nor a programming language. NodeJS is a ...
Read MoreURLSearchParams.has & delete() in Node
Introduction to has()This function returns true or false based upon the query argument. The function will return true if name-value pair exists for the argument.Syntaxvar bool = URLSearchParams.has(name);It will return TRUE if name is present, else FALSE.ParametersThe input parameter is a name that needs to be searched in the URL.Example // Defining the URL as a constant const myURL = new URL( 'https://example.org/?firstName=John'); // Printing whether the argument exists or not console.log(myURL.searchParams.get('firstName'));OutputtrueExample// Defining the URL as a constant const myURL = new URL( 'https://example.org/?firstName=John'); // Printing whether the argument exists or not console.log(myURL.searchParams.get('lastName'));OutputfalseIntroduction to delete()It will delete/remove ...
Read MoreSync vs Async vs Async/Await in fs-extra - NodeJS
Introduction to fs-extraBefore proceeding with fs-extra, one must have a basic knowledge of the fs file system. The fs-extra is an extension of the fs file system and has more methods than it. It adds some file method systems that are not there in the naive fs modules. Fs-extra adds the promise support to the fs methods and therefore better than fs.Installationnpm install fs-extraSyntaxfs-extra is a replacement for the native fs file system. All methods that are in fs are attached to fs-extra as well. Therefore, you don't need to include fs again.const fs = require('fs-extra');Most methods provided by fs-extra ...
Read MorereadJson() function in fs-extra - NodeJS
readJson() method reads a JSON object and then parses it into an object.SyntaxreadJson(file [, options] [, callback])Parametersfile – String parameter which will contain name and location of the file holding the JSON.options – The 'outputFile' function supports the following options −encoding – Default 'null'.flag – Default 'r'. The flag 'r' opens a file for reading and an exception will occur if file does not exist.signal – allows aborting an ongoing output file functioncallback – This function will give a callback if any error occurs.Example 1Check that fs-extra is installed before proceeding; if not, install fs-exra.You can use the following command to check whether fs-extra is installed ...
Read MoreQuerying Data from Table using Node
In this article, we will see how to select or query the data from a database based on different table fields and columns.Before proceeding, please check the following steps are already executed −mkdir mysql-testcd mysql-testnpm init -ynpm install mysqlThe above steps are for installing the Node - mysql dependecy in the project folder.Select Data from Table Using NodeCreate a new file with the following name – app.jsCopy and Paste the following code snippet in this file.Now, run the following command to check the output of the above program.>> node app.jsExample// Checking the MySQL dependency – if exists var mysql = ...
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