Error-first callbacks are used to pass errors and data. If something goes wrong, the programmer has to check the first argument because it is always an error argument. Additional arguments are used to pass data. fs.readFile(filePath, function(err, data) { if (err) { //handle the error } // use the data object });
Global installation of dependencies is stored in /npm directory. While local installation of dependencies stores in the local mode. Here local mode refers to the package installation in node_modules directory lying in the folder where Node application is present. Globally deployed packages cannot be imported using require() in Node application directly. On the other hand, …
All the API’s of Node.js library are asynchronous means non-blocking. A Node.js based server never waits for an API to return data. The Node.js server moves to the next API after calling it, and a notification mechanism of Events of Node.js responds to the server for the previous API call.
The Node.js provides Buffer class to store raw data similar to an array of integers but corresponds to a raw memory allocation outside the V8 heap. It is a global class and can be accessed in an application without importing a buffer module. Buffer class is used because pure JavaScript is not compatible with binary …
To avoid callbacks, you can use any one of the following options: You can use modularization. It breaks callbacks into independent functions. You can use promises. You can use yield with Generators and Promises.
The Node.js Assert is a way to write tests. It provides no feedback when running your test unless one fails. The assert module provides a simple set of assertion tests that can be used to test invariants. The module is intended for internal use by Node.js, but can be used in application code via require …
Yes, Node.js provides a simple TCP based protocol and built-in debugging client. For debugging your JavaScript file, you can use debug argument followed by the js file name you want to debug. Syntax: node debug [script.js | -e “script” |<host>:<port> :]
The Streams are the objects that facilitate you to read data from a source and write data to a destination. There are four types of streams in Node.js: Readable: This stream is used for reading operations. Writable: This stream is used for write operations. Duplex: This stream can be used for both reading and write …
Control flow function is a generic piece of code that runs in between several asynchronous function calls.
In Node.js, event-driven programming means as soon as Node starts its server, it initiates its variables, declares functions and then waits for an event to occur. It is one of the reasons why Node.js is pretty fast compared to other similar technologies.
