Introduction to Async ensureFile()This method is used to ensure that a file exists at the given location. If the files that is ensured to be created is not present or the respective directories are not present, these directories and files are created. If the file already exists, it is not modified or no change is made.SyntaxensureFile(file, [, callback])Parametersfile – String parameter which will contain name of the file and its location that needs to be ensured.callback – 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 ... Read More

NodeJS provides inbuilt library crypto to encrypt and decrypt data in NodeJS. We can use this library to encrypt data of any type. You can do the cryptographic operations on a string, buffer, and even a stream of data. The crypto also holds multiple crypto algorithms for encryption. Please check the official resources for the same. In this article, we will use the most popular AES (Advanced Encryption Standard) for encryption.Configuring 'crypto' dependencyIn your project, check if NodeJS is initialized or not. If not, use the following command to initialize NodeJS.>> npm init -yThe 'crypto' library is automatically added while ... Read More

This method is used to empty a directory whether it is empty or not with a sync process. If the directory is not empty, it will remove all its contents and empty it. A new empty directory is created if the directory does not exist.SyntaxemptyDirSync(dir)Parametersdir – This is a string paramter which will hold the location of the directory structure.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 or not.npm ls fs-extraCreate a syncEmptyDir.js and copy-paste the following code snippet into that file.Now, run the following ... Read More

Introduction to Async emptyDir()This method is used to empty a directory whether it is empty or not. If the directory is not empty it will remove all its contents and empty it. A new empty directory is created if the directory does not exist.SyntaxemptyDir(dir, [, callbacks])Parametersdir – This is a string paramter which will hold the location of the directory structure.callback – 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 or not.npm ls fs-extraCreate a asyncEmptyDir.js ... Read More

You can delete an existing table from MySql Database using the "DROP TABLE" statement in Node. Sometimes, we need to delete the whole table, though in corporates it is always advised to archive the tables which are not in used instead of deleting them.While deleting a table, we have two scenarios −Deleting a table if it exists, else throw an errorDeleting the table whether it exists or not.We will discuss both the scenarios here.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 ... Read More

NodeJS is a JavaScript runtime environment that was built on top of Chrome's V8 engine. The traditional use of JavaScript is to be executed in browsers, but with Node.JS we can execute JavaScript other than browsers like servers, hardware devices, etc.process.cwd()The process object lies under the global object known as 'global'. This method provides information about the current process of Node.js. It also provides control over the same. cwd refers to the current working directory of the same. Therefore, process.cwd returns the working directory on which execution is taking place currently.__dirnameThis is a local module that will return the directory ... Read More

Both the methods – console.log and process.stdout.write have a basic definition to write or print the statements on the console. But, there is a slight difference in the way they execute these tasks. Internally, console.log implements process.stdout.write which itself is a buffer stream that will be used to directly print statements on your console.process.stdout.writeconsole.logIt continuously prints information as retrieved from the stream without adding any new line.It first prints the information being retrieved and then adds a new line. Then it will go to retrieve the second set of statements to print.The process.stdout.write method takes only string as paramter. Other ... Read More

Introduction to SequelizeSequealize follows the promise-based Node.js ORM for different servers like – Postgres, MySQL, MariaDB, SQLite, and Microsoft SQL Server.Following are some of the main features of NodeJS sequelize −Transaction SupportRelationsEager and Lazy LoadingRead Replication and more...Connecting to MySQL using SequelizeWe need to establish a connection between MySQL and Node.js using Sequelize.After creating a successful connection with sequelize, we would require the following three files for configuration. Please carefully create the following files in their respective folders only.SequelizeDemo > application.jsThis will be our root file which will hold the actual logic.SequelizeDemo>utils>database.jsThis will hold all the connection details to MySQL.SequelizeDemo>models>user.jsThis ... Read More

Introduction to mongodb.connectThis method is used to connect the Mongo DB server with our Node application. This is an asynchronous method from MongoDB module.Syntaxmongodb.connect(path[, callback])Parameters•path – The server path where the MongoDB server is actually running along with its port.•callback – This function will give a callback if any error occurs.Installing Mongo-DBBefore proceeding to try connect your application with Nodejs, we need to setup our MongoDB server first.Use the following query to install mongoDB from npm.npm install mongodb –saveRun the following command to set up your mongoDB on the specific localhost server. This will help in creating connection with the ... Read More

Introduction to Async copyThis method copies files or directories from one location to another location. The directory can have sub-directories and files.Syntaxcopy(src, dest[, options][, callback])Parameterssrc – This is a string paramter which will hold the source location of the file or directory that needs to be copies. If the location is a directory, it will copy everything inside of the directory instead of whole directory.dest – This will hold the destination location where the files/directories will be copies. If src is a files, dest cannot be a directory.options −overwrite – If set to true, existing files or directories will be ... Read More