Angular Interview : is Angular Service Singleton ?

One of the most popular Angular interview questions is, whether a service is singleton? By default, when you create a service using the below CLI command, ng g s app AppService is singleton, however it can be re-provided to create more objects of it. Say, you again re provide AppService in one of the components, … Continue reading Angular Interview : is Angular Service Singleton ?

Closures in JavaScript: Video

A JavaScript closure is a function which remembers the environment in which it was created. We can think of it as an object with one method and private variables. JavaScript closures are a special kind of object which contains the function and the local scope of the function with all the variables (environment) when the … Continue reading Closures in JavaScript: Video

Joined MongoDB

I am very excited to inform you all that I have joined esteem MongoDB starting 5th October 2020.  I have joined the Professional Services Team and will be working from Gurgaon, India. At MongoDB, my primary responsibility is to work closely with engineers and make a world-class training curriculum for them and our customers.  I … Continue reading Joined MongoDB

Union and Intersection of types in TypeScript

Do you know, TypeScript allows union and Intersection of types? Why you need that? Let us assume you need to create a function that checks whether the passed value is boolean true and returns true, otherwise returns null. That function may look like below, function trueOrNull(foo: any): any {     if (foo === true) {         return true;     }     return undefined; } console.log(trueOrNull(88)); // null  As you see, the … Continue reading Union and Intersection of types in TypeScript

Recognized as Progress Ninja

I am very excited to share that I have been recognized as Progress Ninja by Progress Telerik. Thanks,  Progress Telerik, for recognizing me as one of the Progress Ninja. I am happy and excited to work with the Progress developer community and developer community in general. As of now, there are six Progress Ninjas, … Continue reading Recognized as Progress Ninja

Video – Step by Step Create Node.js REST API with SQL Server Database

In this video, learn to create a Node.js API to perform CRUD operations on a database in SQL Server. You can find the source code here : For notifications of the further videos, subscribe to the <geek97/> Youtube channel here :

Master RxJS: Part 2 – What is an observer

This is the second post in the Master RxJS series. The first post is a video tutorial that explains, why RxJS Watch it here: In this post, we will discuss an observer in RxJS. An observer is an object with three call-back functions to subscribe to the notifications from an Observable. Too much technical … Continue reading Master RxJS: Part 2 – What is an observer

How to make the length of an Array read-only in JavaScript

Sometimes, you may come across a requirement that once the array is created, its length should not be changed. In this blog post, let us explore how you can achieve that. Let us say you have an array as shown below, let foo = ['1', '11']; console.log(foo.length); // 2 console.log(foo[1]); //11 As you see, the length of the array is 2, and … Continue reading How to make the length of an Array read-only in JavaScript

Change Detection in Angular

Change Detection is the backbone of the Angular framework, and each component has its own change detector. This article explains change detection strategies and optimizations to help you write highly performant Angular applications. Angular can detect when data changes in the component, and can re-render the view to display the updated data. Angular makes sure … Continue reading Change Detection in Angular