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Node.js Articles
Page 16 of 22
async.queue() Method in Node.js
The async module provides different functionalities to work with asynchronous JavaScript in a nodejs application. The async.queue() method returns a queue that is further used for concurrent processing of processes i.e. multiple processing of items at a time/instant.Installing and Using async.queue()Step 1 − Run the following command to initialize the node package manager.npm initStep 2 − Installing the async module using the following command.npm install --save asyncStep 3 − Importing the async module using the below statement in your programs .const async = require('async')Syntaxasync.queue('function', 'concurrency value')ParametersThe above parameters are described as below −function – This parameter defines the function that will ...
Read Moreagent.maxFreeSockets Property in Node.js
The agent.maxFreeSockets property defines the number of sockets that are left open while in the free state. This is a part of the 'http' module interface.Syntaxagent.maxFreeSockets : numberParametersThe above function can accept the following parameters −number – This defines the number of sockets that can be kept open in the free state. Its default value is set to 256.ExampleCreate a file with name – maxFreeSockets.js and copy the below code snippet. After creating file, use the following command to run this code as shown in the example below −node maxFreeSockets.jsmaxFreeSockets.js −// agent.maxFreeSockets method Demo example // Importing the http & ...
Read Morecrypto.createDiffieHellman() Method in Node.js
The above method creates a DiffieHellman key exchange object with the help of the supplied prime value and an optional specific generator. The generator argument can hold either a string, number or Buffer value. Default value for generator is 2.Syntaxcrypto.createDiffieHelmmanGroup(prime, [primeEncoding], [generator], [generatorEncoding]ParametersThe above parameters are described as below −prime – The number of prime bits that will be generated. Input value is of type number.primeEncoding – This parameter defines the encoding of the prime string. Possible input types are: string, buffer, TypedArray and DataView.generator – Generator for generating the exchange key object. Default value: 2.generatorEncoding – This parameter defines the generator string encoding.ExampleCreate ...
Read MoreLogging in Node.js
Logging is a very essential part in any application whether it is made in Node.js or any other programming languages. Logging helps us to detect weird behaviours of an application along with real-time errors and exceptions. One should definitely put logical logs in their application. These logs help the user to identify any mistakes and resolve it on urgent basis.There are 5 different log levels which are present at the moment with the user. These log levels are used to define different kinds of logs and helps the user to identify different scenarios. The log levels must be carefully configured ...
Read MoreChanging the npm start-script of Node.js
The start-script of a Node.js application consists of all the commands that will be used to perform the specific tasks. When starting or initializing a Node.js project, there are a lot of predefined scripts that will be created for running the application. These scripts can be changed as per the need or demand of the project.Script commands are widely used for making different startup scripts of programs in both Node and React. 'npm start' is used for executing a startup script without typing its execution command.Package.json FileThis is the start-up script that needs to be added in the package.json file. ...
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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