Trinity  Kub

Trinity Kub


Scheduling in React 16.x

What is the scheduler?

Let’s start with some theory.

JavaScript is a single-threaded language. This means we have one call stack which can perform one piece of code at the time. Among executing your code, the browser needs to perform a different kind of work. This includes:

  • managing events (user clicks handlers, setTimeout callbacks, etc.)
  • layout calculations (building DOM / CSSOM) and
  • repaints (based on the layout calculations)

Let’s focus on the last one. Within one second, browsers usually repaint 60 times, which means there is a single repaint every 16.6ms (more or less, depending on the environment).

When you run a piece of synchronous code for about one second, you will accidentally drop ~60 frames which introduces delays, hits UX, and makes your app unresponsive.

So, the primary objective of the scheduler is to balance between all the activities being performed within the browser, not starve any of them as well as keeps your app repaint-aware.

But, as developers, should we care? No doubt, we should be aware of the problem. Nowadays, we outsource quite a lot of responsibilities to third party entities while developing our apps.

Web frameworks do a lot for us, they manage routing and state, provide change-detection mechanisms, two-way-data-binding (Angular/Vue.js), update DOM directly, and many, many more. They act as a middleware between us and the browser, so it seems to be a great place for scheduling problem to be solved, right?

And web frameworks do so. There is no exception for React as well (at least, React 16.x).

Trying to implement a simple scheduler

I will explain how it is managed by React, but, to understand the underlying problem, let’s write some simple piece of code…

Let’s simulate a heavy browser app:

setInterval(() => {
}, 3)

It forces the browser to do a repaint (caused by DOM manipulations being made each 3 ms). Now, consider this code:

setInterval(() => {
}, 3)

function render() {
    for (let i = 0; i < 20; i++) {
function performUnitOfWork() {
function sleep(milliseconds) {
    // sleep for given {milliseconds} period (synchronous)

What is the impact of our browser rendering mechanism? Well, render is synchronous, so it freezes browser for 100ms (20 * 5ms = 100ms). No repaint can be made within the time. User input events callbacks neither. Let’s take a look into Chrome’s “Performance tool” output for a given code:

In the example, we drop frames for more than 100ms (see vertical dotted lines, they show you when the frame ends). As mentioned earlier — the browser does a repaint each ~16.6 ms (60 frames per second). In this case, repaints are delayed which freezes any animation performing at the time. User input handlers are delayed as well. This is not what we want, right?

Now, let’s assume the provided render function is a React 15.x implementation of render mechanism. During the process, React tracks changes, calls our life-cycle methods, compares props, etc. It is a time-consuming process that might take a long time to compute, especially in heavy apps.

Does the React 15.x have a scheduler mechanism at all? Nope, it does not, so there is no difference between our synchronous render function and React 15.x render implementation.

And in the Internet there is a great example presenting how React 15.x manages heavy app, which includes both quite a lot of browser repaints (resizing) as well as JavaScript computation (life-cycle methods execution):

React 15.x render problems

React 15.x render problems

See how it works here. Quiet laggy, right? Let’s go back to our example… How can we improve this synchronous-based rendering mechanism? How about adding setTimeout?


function render() {
    setTimeout(render, 0)

What are the results?

Yep, way better, our frames are no longer delayed. Our _performUnitOfWork_ function is being handled separately, on each frame. Repaints are being made regularly — with no frame delay.

So, is it the way the scheduling problem is being solved for React 16.x apps? Not really. Among entire internal engine rewrite (so-called React Fiber) React team has introduced a dedicated module (“React Scheduler”) to address scheduling issues. How it works? I will explain it soon, but firstly — we need to introduce… Channel Messaging API.

#software-engineering #web-development #react #javascript #programming

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Scheduling in React 16.x
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.

#android app #frontend #ios app #mobile app development #benefits of react native #is react native good for mobile app development #native vs #pros and cons of react native #react mobile development #react native development #react native experience #react native framework #react native ios vs android #react native pros and cons #react native vs android #react native vs native #react native vs native performance #react vs native #why react native #why use react native

Mathew Rini


How to Select and Hire the Best React JS and React Native Developers?

Since March 2020 reached 556 million monthly downloads have increased, It shows that React JS has been steadily growing. React.js also provides a desirable amount of pliancy and efficiency for developing innovative solutions with interactive user interfaces. It’s no surprise that an increasing number of businesses are adopting this technology. How do you select and recruit React.js developers who will propel your project forward? How much does a React developer make? We’ll bring you here all the details you need.

What is React.js?

Facebook built and maintains React.js, an open-source JavaScript library for designing development tools. React.js is used to create single-page applications (SPAs) that can be used in conjunction with React Native to develop native cross-platform apps.

React vs React Native

  • React Native is a platform that uses a collection of mobile-specific components provided by the React kit, while React.js is a JavaScript-based library.
  • React.js and React Native have similar syntax and workflows, but their implementation is quite different.
  • React Native is designed to create native mobile apps that are distinct from those created in Objective-C or Java. React, on the other hand, can be used to develop web apps, hybrid and mobile & desktop applications.
  • React Native, in essence, takes the same conceptual UI cornerstones as standard iOS and Android apps and assembles them using React.js syntax to create a rich mobile experience.

What is the Average React Developer Salary?

In the United States, the average React developer salary is $94,205 a year, or $30-$48 per hour, This is one of the highest among JavaScript developers. The starting salary for junior React.js developers is $60,510 per year, rising to $112,480 for senior roles.

* React.js Developer Salary by Country

  • United States- $120,000
  • Canada - $110,000
  • United Kingdom - $71,820
  • The Netherlands $49,095
  • Spain - $35,423.00
  • France - $44,284
  • Ukraine - $28,990
  • India - $9,843
  • Sweden - $55,173
  • Singapore - $43,801

In context of software developer wage rates, the United States continues to lead. In high-tech cities like San Francisco and New York, average React developer salaries will hit $98K and $114per year, overall.

However, the need for React.js and React Native developer is outpacing local labour markets. As a result, many businesses have difficulty locating and recruiting them locally.

It’s no surprise that for US and European companies looking for professional and budget engineers, offshore regions like India are becoming especially interesting. This area has a large number of app development companies, a good rate with quality, and a good pool of React.js front-end developers.

As per Linkedin, the country’s IT industry employs over a million React specialists. Furthermore, for the same or less money than hiring a React.js programmer locally, you may recruit someone with much expertise and a broader technical stack.

How to Hire React.js Developers?

  • Conduct thorough candidate research, including portfolios and areas of expertise.
  • Before you sit down with your interviewing panel, do some homework.
  • Examine the final outcome and hire the ideal candidate.

Why is React.js Popular?

React is a very strong framework. React.js makes use of a powerful synchronization method known as Virtual DOM, which compares the current page architecture to the expected page architecture and updates the appropriate components as long as the user input.

React is scalable. it utilises a single language, For server-client side, and mobile platform.

React is steady.React.js is completely adaptable, which means it seldom, if ever, updates the user interface. This enables legacy projects to be updated to the most new edition of React.js without having to change the codebase or make a few small changes.

React is adaptable. It can be conveniently paired with various state administrators (e.g., Redux, Flux, Alt or Reflux) and can be used to implement a number of architectural patterns.

Is there a market for React.js programmers?
The need for React.js developers is rising at an unparalleled rate. React.js is currently used by over one million websites around the world. React is used by Fortune 400+ businesses and popular companies such as Facebook, Twitter, Glassdoor and Cloudflare.

Final thoughts:

As you’ve seen, locating and Hire React js Developer and Hire React Native developer is a difficult challenge. You will have less challenges selecting the correct fit for your projects if you identify growing offshore locations (e.g. India) and take into consideration the details above.

If you want to make this process easier, You can visit our website for more, or else to write a email, we’ll help you to finding top rated React.js and React Native developers easier and with strives to create this operation

#hire-react-js-developer #hire-react-native-developer #react #react-native #react-js #hire-react-js-programmer

What are hooks in React JS? - INFO AT ONE

In this article, you will learn what are hooks in React JS? and when to use react hooks? React JS is developed by Facebook in the year 2013. There are many students and the new developers who have confusion between react and hooks in react. Well, it is not different, react is a programming language and hooks is a function which is used in react programming language.
Read More:-

#react #hooks in react #react hooks example #react js projects for beginners #what are hooks in react js? #when to use react hooks

Aria Barnes

Aria Barnes


React 18: Things You Need To Know About React JS Latest Version

The most awaited version of React 18 is finally out now. Its team has finally revealed the alpha version of React 18 and its plan, though the official launch is still pending. This time the team has tried something and released the plan first to know their user feedback because the last version of React 17 was not that much appreciated among developers.

According to Front-end Frameworks SurveyReact JS has ranked top in the list of most loved frameworks. Thus, the developer communities expect a bit higher from the framework, so they are less appreciative of the previous launch.
ReactJS stats.pngSo, this time React 18 will be a blast. For beginners, the team is working on a new approach. They have called a panel of experts, library authors, educators, and developers to take part in a working group. Initially, it will be a small group.

I am not a part of this release but following the team on their GitHub discussion group. After gathering the information from there, I can say that they have planned much better this time.

React 17 was not able to meet the developer's community. The focus was all primarily centered on making it easier to upgrade React itself. React 18 release will be the opposite. It has a lot of features for react developers.

Read more here: React 18: Things You Need To Know About React JS Latest Version

#hire react js developers #hire react js developers india #react developers india #react js developer #react developer #hire react developers

Aubrey  Price

Aubrey Price


Build a simple React Native Pokemon app with React-Navigation

As we start learning new technologies we want to start building something or work on a simple project to get a better understanding of the technology. So, let’s build this simple app.
For this app, we will be using PokeApi to get our pokemon data, and also we will be using Hooks. I am using pokemondb for pokemon sprites. It’s just a personal preference you can use whatever you want.

#react-native #react-native-app #react-navigation #react-native-development #react