Angular vs. React: Change Detection

In this post, I’m going to discuss how Angular and React differ in their change detection strategies.

A basic knowledge of both React and Angular is a prerequisite for this article.

Let’s get started.

What is Change Detection (CD)?

CD is the process of detecting whether the application’s UI should be updated (and, if so, which parts to update) when changes to the underlying model come in through user interaction or through the network.

Change Detection in Angular


The process of CD is initiated any time one of the following happens:

  • An event generated by the user in the UI, like a button click, form submission, etc.
  • A timing event like setTimeout.
  • A network event (like an incoming HTTP response from the server).

Notifications about timing and network events are made possible through a library called zone.js.

Now, whenever any of the above events take place, Angular:

  • gets its notification by intercepting the event listener function.
  • schedules a CD cycle to be run after the application code has finished updating due to the event.

The Process

  1. When Angular first processes the application code, it makes a note of all associations between the HTML properties and the TS (or JS) properties. Then it goes about creating what can technically be called “bindings” (for each HTML-property-TS-property association). A binding is basically a set of instructions.
  2. After bindings have been created, Angular only deals with the bindings for CD and not with the entire application code.
  3. Now, when Angular is notified of an event, all bindings are re-evaluated. This process is called dirty-checking.
  4. The binding for which a property has changed is marked as updated (or dirty).
  5. Next, the DOM is re-created with the latest bindings.
  6. By default, Angular scans all the bindings each time an event happens, to look for changes.

Angular vs. React

Bindings between HTML and TS properties

Change Detection in React


When the props to a component or the state of the component changes, render() function is called, by default.

Every time render() is called, React’s CD runs.

The process

  1. Each time render() is executed, React creates a virtual DOM object based on the JSX returned by render(). The virtual DOM is called “virtual” because it’s a replica of the real DOM — a lightweight JavaScript replica object representing the data structures and data of the component.
  2. Subsequently, each time render() is executed, a new version of the virtual DOM is created. This latest virtual DOM is compared with the immediately previous version, using a diffing algorithm.
  3. The diffing algorithm comes up with the minimum number of steps to update the real DOM, in O(n) time, making it really efficient. Based on whatever changes were detected by this diffing algorithm, a patch is created and scheduled to be applied to the real DOM.
  4. React considers dirty only those components for which the state/props changed.
  5. CD cycles are batched. This means that while React is busy updating the real DOM, all the CD requests that come in are batched together and are brought into effect only after the previous DOM update cycle has ended.

What about the Virtual DOM?

Updating the real DOM is much more expensive and time-consuming than updating the virtual DOM. This is because, while the virtual DOM is a lightweight JavaScript object (and it’s quick to update), updating the real DOM involves a lot of other processes too. Processes like processing and applying the CSS, setting the exact coordinates of all elements on the screen, traversing the DOM tree, rendering it, etc.


CD is the process by which the application’s UI and model stay in sync with each other.

Angular creates bindings between the HTML and TS, intercepts the calls to the registered event listeners, processes all bindings, and updates the DOM.

React keeps an eye on render(). As soon as the latter is invoked, a virtual DOM object is created and compared with the previous version of the virtual DOM. Changes are calculated, batched, and a DOM update is scheduled.

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Angular vs. React: Change Detection
Autumn  Blick

Autumn Blick


How native is React Native? | React Native vs Native App Development

If you are undertaking a mobile app development for your start-up or enterprise, you are likely wondering whether to use React Native. As a popular development framework, React Native helps you to develop near-native mobile apps. However, you are probably also wondering how close you can get to a native app by using React Native. How native is React Native?

In the article, we discuss the similarities between native mobile development and development using React Native. We also touch upon where they differ and how to bridge the gaps. Read on.

A brief introduction to React Native

Let’s briefly set the context first. We will briefly touch upon what React Native is and how it differs from earlier hybrid frameworks.

React Native is a popular JavaScript framework that Facebook has created. You can use this open-source framework to code natively rendering Android and iOS mobile apps. You can use it to develop web apps too.

Facebook has developed React Native based on React, its JavaScript library. The first release of React Native came in March 2015. At the time of writing this article, the latest stable release of React Native is 0.62.0, and it was released in March 2020.

Although relatively new, React Native has acquired a high degree of popularity. The “Stack Overflow Developer Survey 2019” report identifies it as the 8th most loved framework. Facebook, Walmart, and Bloomberg are some of the top companies that use React Native.

The popularity of React Native comes from its advantages. Some of its advantages are as follows:

  • Performance: It delivers optimal performance.
  • Cross-platform development: You can develop both Android and iOS apps with it. The reuse of code expedites development and reduces costs.
  • UI design: React Native enables you to design simple and responsive UI for your mobile app.
  • 3rd party plugins: This framework supports 3rd party plugins.
  • Developer community: A vibrant community of developers support React Native.

Why React Native is fundamentally different from earlier hybrid frameworks

Are you wondering whether React Native is just another of those hybrid frameworks like Ionic or Cordova? It’s not! React Native is fundamentally different from these earlier hybrid frameworks.

React Native is very close to native. Consider the following aspects as described on the React Native website:

  • Access to many native platforms features: The primitives of React Native render to native platform UI. This means that your React Native app will use many native platform APIs as native apps would do.
  • Near-native user experience: React Native provides several native components, and these are platform agnostic.
  • The ease of accessing native APIs: React Native uses a declarative UI paradigm. This enables React Native to interact easily with native platform APIs since React Native wraps existing native code.

Due to these factors, React Native offers many more advantages compared to those earlier hybrid frameworks. We now review them.

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Why the industries are choosing to react instead of angular - INFO AT ONE

Angular JS is a typescript-based application developed by Google. It’s an open-source web application framework, specifically made for the front end Web developers. As we know that the Angular is created by Google it gets very good support from Google and some individual communities of developers.

Read More:-

#angular #angular and react #js cons of angular #cons of react js #difference between angular and react js #pros of react js

Angular vs. React: Which Is Better and How?

We are living in a technology-mediated world. And, here, we want our hands on the best technology to develop apps. Speaking about the same, we often find ourselves between the simmering debate, what is better between the two- is it Angular or React? And the moment the question pops in our head, we find ourselves comparing the apples and the oranges. Only just, Angular is the framework and the React is a library that helps to create or develop an app. Moreover, both of them work differently to offer somewhat similar functionalities. It is one of the most crucial dilemmas one is faced with, after determining the right mobile development ideas for start-ups.

The Internet is flooded with a plethora of articles on “Angular and React JS. And this debate is consuming a lot of online space is which is better among the two. And, to be very honest we don’t just want to storm your search lists with another yet similar article about the same. So, here is the thing that you should understand about the Angular and React and how these two even being different adds value to the overall website development realm.

What is Angular JS?

AngularJS was always considered as the golden child in the entire family of the JavaScript framework. And, you may wonder why? It was introduced by the renowned giant Google in the year 2009. And, it was then built with the concept “Model-View-Controller”. It is used to build a single page application using Typescript and HTML.

The angular framework further includes the following versions-

Angular 2- When the Angular 2 was released it brought about innumerable changes to the original framework. The architectural style was then switched to that of the component-based one.

Angular 4- With the release of the Angular 4 it brought about more advancement in this realm. It meant that the angular applications can be rendered easily even outside the main browser.

Angular 5–6- The version was concentrated in optimizing the overall Angular CLI as well as the compiler work.

Angular 7- In this version, the functions while using Angular became more intuitive. Moreover, the applications received a plethora of improvements in the size as well as the performance of code-base.

Angular 8- It is the latest version of Angular. In this version, two new elements were introduced which were mainly, Bazel as well as Ivy Renderer. The other most important improvement that this version entailed was differential loading. Speaking about the differential loading, it is used to upload browser-specific bundles. And, you may wonder how beneficial can be both? The browser-specific bundles are further used to assist in uploading the content fast and support the legacy browser.

#angular #angular-vs-react #react #front-end-development #angularjs

Karine  Crooks

Karine Crooks


What every front-end developer should know about change detection in Angular and React.

In my pursuit to grow as a developer I spend a lot of time reverse-engineering web technologies. I’m basically a reverse-engineering addict. The topic that fascinates me the most is change detection. You can find this mechanism in almost any web application. It’s an integral part of the most popular web frameworks. Sufficiently advanced widgets, like datagrids or stateful jQuery plugins, have change detection. And there’s a good chance that change detection lurks somewhere in your application’s code base.

Every aspiring software architect must have a good understanding of this mechanism. I’d argue that change detection is the most important piece of an architecture since it’s responsible for the visible part like DOM updates. It’s also the area that significantly affects an application’s performance. This article will greatly expand your knowledge in this domain.

We’ll start by looking at the change detection in general. Then we’ll implement a very basic change detection mechanism ourselves. And once we’ve established the essence of change detection, we’ll take an in-depth look at how it’s implemented in Angular and React.

#angular #react #change-detection #reconciliation #frameworks

Christa  Stehr

Christa Stehr


Install Angular - Angular Environment Setup Process

Angular is a TypeScript based framework that works in synchronization with HTML, CSS, and JavaScript. To work with angular, domain knowledge of these 3 is required.

  1. Installing Node.js and npm
  2. Installing Angular CLI
  3. Creating workspace
  4. Deploying your First App

In this article, you will get to know about the Angular Environment setup process. After reading this article, you will be able to install, setup, create, and launch your own application in Angular. So let’s start!!!

Angular environment setup

Install Angular in Easy Steps

For Installing Angular on your Machine, there are 2 prerequisites:

  • Node.js
  • npm Package Manager

First you need to have Node.js installed as Angular require current, active LTS or maintenance LTS version of Node.js

Download and Install Node.js version suitable for your machine’s operating system.

Npm Package Manager

Angular, Angular CLI and Angular applications are dependent on npm packages. By installing Node.js, you have automatically installed the npm Package manager which will be the base for installing angular in your system. To check the presence of npm client and Angular version check of npm client, run this command:

  1. npm -v

Installing Angular CLI

  • Open Terminal/Command Prompt
  • To install Angular CLI, run the below command:
  1. npm install -g @angular/cli

installing angular CLI

· After executing the command, Angular CLI will get installed within some time. You can check it using the following command

  1. ng --version

Workspace Creation

Now as your Angular CLI is installed, you need to create a workspace to work upon your application. Methods for it are:

  • Using CLI
  • Using Visual Studio Code
1. Using CLI

To create a workspace:

  • Navigate to the desired directory where you want to create your workspace using cd command in the Terminal/Command prompt
  • Then in the directory write this command on your terminal and provide the name of the app which you want to create. In my case I have mentioned DataFlair:
  1. Ng new YourAppName

create angular workspace

  • After running this command, it will prompt you to select from various options about the CSS and other functionalities.

angular CSS options

  • To leave everything to default, simply press the Enter or the Return key.

angular setup

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