Hire the Top 3% of Freelance React.js Consultants

React is a JavaScript library for building user interfaces (UIs) that was introduced by Facebook in March of 2013. It is increasingly becoming the go-to option for both developers and executives seeking a low-risk, interoperable, and reusable foundation for building their web and mobile applications.

Besides Facebook itself, the number of high-profile companies using React is massive and grows daily, including Airbnb, Walmart, Zillow, Wolfram Alpha, WeWork, and many others.

Maybe you’ve already been considering React. Maybe you’re planning a new project and want to know what all the hype is about. Or maybe you want to re-architect an existing application or implement some new features within a large app.

Whatever your use case, we believe that React and its surrounding ecosystem will support that use case well and allow you to grow without the constraints usually found in legacy application architectures.

Brief React Programming Overview

React allows developers to implement interfaces in a composable, declarative way through the JSX syntax. For instance, the structure for an app may be implemented like this:

<div>
  <AppHeader authStatus={props.authenticated} user={props.user} />
  <AppContent>
    <UserFeed data={props.users} />
    <TickerFeed data={props.tickerData} />
    <AccountFinanceInfo data={props.financeData} />
  </AppContent>
  <AppFooter />
</div>

AppHeader, referred to as a “component,” may represent a brand logo, a list of primary navigation links, an authentication status, and a login widget. You can think of each component as its own “mini app.”

In fact, React applications can be structured in such a way that a large set of features can be shared as modules between code bases, or individual features implemented as standalone applications which can then be included in any JavaScript application or HTML page.

This composability allows developers to build applications that are easy to reason about and maintain, and even allows non-technical users more visibility into the structure of an application.

React is also fast at rendering the application (i.e., turning React code into HTML, CSS, and JavaScript in the DOM) and figuring out which updates should trigger DOM changes due to its unique “diffing” algorithm. Essentially, React knows what parts of your application should render based on changes to parameters passed to individual components. In addition, a variety of convenient lifestyle methods exist which allow developers to conveniently hook into various parts of this rendering sequence, giving the developer control (when necessary) to jump in and tell React what should and should not trigger a render.

Since React has a small footprint and does not force an application architecture, it can be (and is) used alongside existing frameworks and libraries. It is common to see projects which implement different pieces in competing frameworks for various reasons, including the skillsets of available development talent and the interoperability of legacy technologies.

Because of React’s simple design and fuss-free implementation, a variety of architectures can be utilized, and an incredible ecosystem of libraries augment React’s offering by introducing clean patterns for data management, network calls, internal event flow, and data structures.

In fact, Facebook defines patterns, such as Flux, but simply describes the architecture and allows libraries like Redux and Alt to take over the implementation.

Facebook also maintains libraries, such as Jest (for testing), Immutable (for better JavaScript data structures), and React Native (for using React code in mobile environments). In choosing React, your organization will be utilizing code maintained by one of the most sophisticated software development organizations in the world for their own needs.

Small libraries that work well together are more reminiscent of a Linux approach than a monolithic architecture. React programming itself is simple enough that its basic usage can be learned in a few days.

Even if a developer is not utilizing the most ideal architecture and ecosystem libraries right away, React work can go into production almost right away, while combining legacy code (such as jQuery network calls or an existing Angular or Backbone application) with new React components.

What this means is that over time, a React-based UI can morph into an architecture that is ideal for the unique business requirements at hand, rather than accepting the “square peg, round hole” approach offered by many monolithic frameworks.

React can also be leveraged inside native mobile codebases using React Native, adding a dimension that few other JavaScript libraries and frameworks can touch, and allowing for code reuse between web and mobile versions of an application without compromising on user experience quality.

Now that you know a bit more about React programming, here are eight clear signs that you’re ready to hire a React developer.

You’re Beginning a New Project and Want to Go with “Cutting-edge” Best Practices

When an organization embarks on a new project, the first questions asked often revolve around which tools, frameworks, and libraries to utilize. For new web applications, React is the obvious choice for foundational code.

Its flexibility, composability, and small footprint, along with the numerous strong libraries available for things like shared state management, form handling, network communication, Bootstrap support, etc. ensure clean, reusable code while maintaining your organization’s ability to remain flexible.

In addition, the development tooling often paired with React is pushing the envelope in every way. The React ecosystem supports advanced concepts like hot reloading and data store interaction for more interactive development. It also features interactive React developer tools available collectively as a browser plugin.

You Have an Existing Project Where Content Changes (Such as Updating Price Tickers) Happen via Manual DOM Manipulations

Just a few years ago, many developers were building applications that would interact directly with the DOM, i.e., they would use the browser API directly to update UI elements with new values.

Imagine a list of stock tickers or other live feed of data, and imagine needing to control adding elements, removing elements, and changing individual elements from hundreds of data sources. This is an approach that is very difficult to maintain.

Through its unidirectional data flow, React simplifies this process a great deal by allowing UI updates to happen automatically through a top-down data flow based on a data change in the component chain. JSX templates receive values from other data structures (such as a plain JavaScript object, an AJAX response, a Flux data store, etc.), and when these values change, the component knows it is receiving new properties and re-renders appropriately. For example:

/* Shows how the component is declared */
<StockTicker symbol="AAPL" price="157.42" />

/* Sample implementation of StockTicker */
function (props) {
  return <div>
    {props.symbol} {props.price}
  </div>
}

This makes implementing applications with many data sources much simpler. You only need to worry about maintaining your application’s internal memory, and not about managing the rendering of the UI, which React conveniently abstracts away.

You Want to Consolidate Your Web and Mobile Applications to Use a Single Code Base

A use case which we are hearing about more and more frequently is that companies want to reuse large portions of their UI structure and logic between platforms.

React Native provides a remarkably elegant way to do so, taking advantage of the JavaScript runtime included on iOS and Android to allow implementing components in native code. <AppHeader />, for instance, can be used directly inside an iOS codebase.

The developer still needs to write some native code, but data management, UI structure, and many other things execute within the JavaScript runtime, allowing for a high degree of code reuse across platforms. This means development budgets that go farther and skillsets that are more highly leveragable.

Your Existing Application Is Not Performant Enough, or You’re Worried about Future Performance

Many legacy JavaScript frameworks, especially those that implement two-way data binding through DOM interpolation, simply aren’t performant enough for complex interfaces that include many frequently rendered elements.

Even jQuery and vanilla JavaScript implementations that alter the DOM too frequently will often run into performance walls that React does not.

React can also be rendered from the server, meaning the hard work can happen on your servers and be delivered to your clients fully compiled for rapid painting to the DOM.

You Want to Wrap Legacy Code inside a More Modern Architecture

A big challenge for many organizations is that while they see the clear value presented by React and the accompanying ecosystem, they cannot justify throwing away existing code that works reasonably well. The good news is that a React application can both wrap or be rendered inside of an application implemented using another UI framework.

The reason for this is that a React application instance is bound to a single DOM element. This DOM element can be within or wrapping another application framework. We have frequently observed React projects which wrap Angular code and vice-versa. Libraries have even been written to make this particular interoperability simpler.

Granted, it’s ideal if your applications are developed with conceptual consistency—i.e., you don’t mix frameworks. But the reality of pressing business needs and the hours required to rewrite “code that works” makes this scenario all too common a requirement.

You Want to Make Your Application Easier to Test Automatically

Earlier we discussed React’s composability and how it makes React applications easier to structure and reason about. Another advantage offered by this composability is the ability to isolate system components into discrete pieces which can be individually tested.

Most React components simply render based on a list of properties provided top-down, so testing the effect of modifying the props a component accepts is remarkably simple.

Some React components also manage internal state, which can be controlled via a very simple API. This is also very easy to test.

An outstanding library of test suites for React, such as Jest, as well as interoperability with existing testing tools, such as Karma, Mocha, etc., make React an easy choice.

React can also be rendered without a browser—it is common to see React applications rendered from the server or inside a headless browser—which simplifies testing even further.

You Want to Keep Up with Current Trends

The fact is that React is quickly gaining further traction and consolidating its status as the leading JavaScript framework.

As it gains more mindshare among developers and more footholds in organizations, it will become increasingly important that every organization have at least a toe in React, and some proficiency in developing applications with React and attracting React talent.

Some of the smartest people in the front-end development community are building the tooling commonly used to build, support, and implement patterns within React architectures, and to say that your organization should consider exposure to them is an understatement.

React and the architectural patterns commonly found in the best applications represent an evolution in web development practices that cannot be ignored.

You Are Deeply Concerned with Long Term Maintainability

If you’ve been involved in many software development projects, you know that one of the most important parts of future-proofing your efforts is ensuring that your application can be supported for years to come.

Though the JavaScript ecosystem changes rapidly, React has remained remarkably stable. In fact, despite completely rewriting React in 2017, Facebook managed to keep backwards compatibility.

This stability means that when your team learns React, you can rest assured that this knowledge will be transferable and will stick around for years to come. In fact, Facebook’s own engineering integrity relies on it. Even IBM has blogged about React’s long-term maintainability.

Besides the backwards compatibility and remarkably stable API, one of the main reasons React is more maintainable than other UI libraries is because of its incredible composability. As discussed previously, React components can be embedded within each other, rendered inside raw HTML pages, or bundled as standalone applications with their own bootstrapping process. This flexibility ensures that as your project evolves, you will be able to easily adapt at least the React part of your application to your requirements.

React’s extreme composability will make things like full rewrites a thing of the past in yourcode base, as it is supremely easy to keep the good parts and isolate the bad parts.

Because React components so frequently work in isolation, it is often very easy to hire someone to maintain another developer’s work, and make changes without creating system-wide problems. It is safe to call React and its accompanying ecosystem one of the most easily maintainable approaches in application development.

The Exciting Choice and also the Safe Choice

The React community continues to thrive while pushing the envelope of modern software engineering. Development still proceeds quickly, and search volumes, job postings, and other measures of interest are showing no signs of diminishing.

And yet it maintains a rare stability. There was once a saying in enterprise software circles in the infancy of the software industry: “Nobody ever got fired for choosing IBM.” This is the status React now enjoys in the software world.

Postscript: How Do You Evaluate React Developers?

Assuming you’ve seen the signs and decided to hire someone for React development, how should you find the best one for your project?

While hiring React developers is in many ways similar to hiring JavaScript developers for other positions—these JavaScript interview questions could help in this case—we have found some characteristics that can help you find the best possible candidates.

A good, senior React developer should have a solid foundation of JavaScript-level knowledge. They should know the ins, outs, and quirks of the JavaScript language itself. They should have experience with common ecosystem tools, such as build tools and testing tools, and have experience working with multiple JavaScript frameworks and deploying JavaScript applications to production.

But beyond what’s needed for plain-vanilla JavaScript jobs, the candidate should have some experience with common React architectural patterns. They should be able to discuss the merits of libraries like Immutable.js, describe data flow in a Flux-based architecture, and know a bit about event-based programming models.

In addition, you’ll probably want the candidate to have some working back-end knowledge, as many application development projects often require a tight communication loop between the API designer, the devops automation team, and the front-end team.

Finally, the candidate should of course have a solid working knowledge of React. Things like JSX syntax, component lifecycle methods, higher-order components, and controlled components should all be second nature. This list of interview questions should help get you started with the technical part of interviewing a React developer. Enjoy!