Hire Front-End developer

How to know that the front end developer is the right fit?

Martha Karkosik

Last updated on July 12, 2020 | 25 min read|

Language:

• English
• German

DesignGuideSoftware developmentWeb Development

Before you start reading the article, take 2 minutes of time to understand what frontend development is.

What does a front-end developer do?

Throughout the years, the role of front-end developers have evolved just like the industry but drilled down, they are the ones who connect the worlds of design and technology to create designs for mobile and web applications. They package backend development in a way that makes it attractive, intuitive, and responsive for end users. They take front-end web design files and turn them into HTML, CSS, or JavaScript codes — the three core elements of front-end development.
A front-end developer is the main person who works on everything users see, click, or interact with (input and retrieval of information; i.e., forms) on a website — that is, the front-end. Front-end developers’ work focuses on the user experience, making sure there are no bugs or errors on the front-end, and that the design works across different platforms and browsers.

How can you evaluate a good front-end developer?

Being the brains behind the elements that users interact with, a top-notch front-end developer is one who has been working (and growing) in the industry, has a few years of experience, and has a strong background in coding, testing, integration, as well as graphic and UI/UX design.
With these in mind, here are some things you need to know when looking for freelance front-end developers that would be the right fit not only for your project but for your team and organization as well.

Solid ‘language’ skills

Front-end developers need to master three core skills: HTML, CSS, and JavaScript. These three are the most basic and essential markup languages.
In particular, JavaScript is something a front-end developer candidate should be well-versed in since it is what is needed to build dynamic user interaction. JavaScript is focused on front-end development works, which sets it apart from HTML and CSS. Freelance front-end developers who know these skills like the back of their hands can contribute a lot to a project and a company, especially when it comes to creating a great UX and user interface.

Has a knack for debugging and fixing errors

Top-notch front-end developers would not be able to stand mediocrity — an app has to be great, not just ‘good enough’. As such, they will always be looking to improve the quality of the application by fixing bugs, running manual and automated tests, as well as testing the back-end integrations to make sure that those are properly carrying out the front-end functionality.
Even if there are no bugs or errors, front-end developers will be looking to continuously improve the web application.

Knows the importance of UI/UX

A good front-end developer and web developer will not only be critical on the app functionality but also the user interface (UI) and the user experience (UX). They can build an amazing UI using HTML/CSS/JavaScript without losing sight of the main goal: to get end-users to love a company’s product through the experience.
UI and UX are not for front-end developers alone; it is the collaborative work of different web development professionals. Having said that, it is recommended that freelance front-end developers have a background in this since it will not be easy to contribute to a team without knowing what the other members are doing.

Possesses ‘soft’ skills as well

The importance of soft skills in programming does not need to be explained. The standard interviews and papers during the application should already tell you a lot about freelance front-end developers’ background, their years of experience, if they are skillful, driven, and have the right attitude and commitment to a project. But there are other things one should look for that are often not on paper.

• Detail-Oriented
  A reliable freelance front-end developer is able to look at the bigger picture without forgetting about the minute details of a project. Good attention to detail means they can focus on the different parts of a project as well as how these are implemented.
  The details and complexity of a project will not be a big problem for them; they will still manage to be on top of things.
• Constant learner
  The world of web and front-end development is never static. There will always be new technology, updates, and strategies to learn and explore. Good front-end developers will keep on improving and growing their skill sets, even if not required for their work, just as a hobby. Look for a passion for learning attitude in a front-end web developer.
• Creative
  Since a major part of the work centers on the design, great front-end developers should also be creative. This lets them get around, over, and under the issues that may come up when developing a website or an application. Creativity also helps them find or create solutions; they would know what steps are ideal to solve a problem. Look for a skilled web developer who will be creative enough to get around, over, and under any issues that pop up to ensure a seamlessly functioning website. In addition to being about to find or create solutions, front-end developers should know what course is best to take for solving a problem.

Asking the right questions is another crucial factor in finding out if the candidate for the front-end developer position is the right fit. They should be able to understand complex technical terms,  share and describe ideas in a comprehensive manner, have significant skills and experiences, and they should share the same vision and goals with you.
 
The ideal hire for a front-end developer should have extensive skills in coding and specializes in UI/UX design

Technologies front-end developers should be familiar with

Websites that display web browsers are written in a variety of technologies. The frameworks are increasing in numbers, but in the end, the browser receives code that it can interpret unambiguously – and here, there are not many changes over time.
The Internet is HTML, CSS, and JavaScript. While the first two have always been there, the last one has been seen as “an addition to animating elements” for a long time. This was until the Node.js runtime environment was created, which popularized JavaScript and found its new purposes.

HTML

HTML defines the structure of the document to be displayed by the browser. It defines where the page element will be placed in the tree. The structure itself partly affects the appearance and its purpose is to place the elements in terms of logic and meaning. This HTML structure is built from tags whose names match their function.
A good practice is to construct it in such a way that the tags can be read as a definition of the element that is inside – this is called semantic HTML code.

CSS

CSS is a style sheet that allows you to dress the document structure in colors and other appearance features. You can use it to change fonts, color, and size. In addition to the obvious modifications, it also lets you define the appearance behavior of an element when the computer mouse pointer is pointed at it or the element was pressed earlier. With the help of CSS, you can animate elements (this is the most optimal solution).

JavaScript

The previously mentioned JavaScript with the above mentioned two technologies allows you to add the logic that controls the page. From simple manipulation of the document structure to complex applications performing operations on the user’s side – this is what opened the way for JavaScript to become one of the most desirable technologies on the market.
Transferring the execution of logic to the client and, in the case of websites, to a web browser saves the work of the server and also simplifies the competence of individual elements of the system. JavaScript is only limited by the capabilities of a web browser, which are really powerful!
On a mobile device, we will check the geolocation of the user, as well as the battery status of his device, and on the desktop, we will run a virtual reality supported by a built-in graphics card. Year after year, web browsers are implementing more and more functionalities, causing that soon there will be no project that can’t be done in JavaScript – if not already!

Top front-end frameworks

Angular

Released by Google and later developed by the community. This is a fully-featured approach where the architecture of the framework provides all the necessary elements to build a complete and functional front-end application.
When learning Angular, front-end developers learn how to use the provided foundations properly, unlike React where it is up to the developer to build the application foundations. Among the supplied foundations there are tested solutions for application state management, routing between screens, and handling forms.
The main approach represented is the MVC model, i.e. division into Model-View-Component. The approaches used by Angular evolved with the growth of the community using it, where it became more and more mature from version to version, to such an extent that today it can be called a corporate frontend framework.
The default language for writing in Angular is TypeScript. It’s a superset of JavaScript extended by typing and many useful constructions, which are simply missing in JavaScript. Code written in TypeScript is easier to test, mainly because of typing.

React.js

It’s a sort of Facebook’s answer to Angular, but it has completely different features. Unlike in the competitor’s case, here the core is provided, which is the library to handle the views. And it’s from this small foundation (compared to what Angular gives) that the web developer or front-end developer has to build a web application – so it can be said that React is not a stand-alone tool to build a full SPA application.
Despite this, it is perfect for building even as complex front-end web interfaces as Angular. Because giving responsibility for the remaining foundations of application architecture to the developer does not mean that such solutions are worse. React is characterized by simple syntax and small components.
Facebook has also created a framework for writing mobile applications, and this is React Native – it was a great move because a web developer or front-end developers who can write in React is able to find themselves in React Native and vice versa. This means that if necessary, the web development team can support the mobile team and vice versa. This unification of the React approach and interface saves a lot!

Vue.js

Relatively the freshest of the three, created by a former Google employee and implementing the approach of others in his own way. Despite the lack of a big corporation behind it, it has quite a big community that cares about its development. It is used, among others, by Alibaba.
It is described as a fully functional framework for SPA applications, which is a bit closer to Angular when it comes to the architectural approach. It borrows from React the approach of the composition of components, and from Angular the way of building them. This makes Vue a versatile competitor for front-end development.

I’ve worked with DevsData on numerous projects over the last 3 years and I’m very happy. They demonstrated a strong degree of proactivity, taking time to thoroughly understand the problem and business perspective. The solutions they designed exceeded my expectations.

Jonas Lee

PARTNER & EXECUTIVE VP OF VERUS FINANCIAL LLC;
INVESTOR & SERIAL ENTREPRENEUR

Importance of responsive design

Since the beginning of the smartphone era, the share of desktop computers in the statistics of devices used by Internet users is decreasing. It is simply more convenient and faster to get the information we need from a smartphone. Practically everything is available in seconds and in a very convenient form.
Computers have missed the revolutions a bit, but still, their market share is so large that it cannot be said that people do not use them. In the context of responsiveness, i.e. adapting the website in such a way that its appearance is properly displayed on any device – freelance front-end developers have to take into account all available devices on the market, including tablets, TVs, and even smartwatches.
In the case of websites, the responsiveness is based on appropriate scaling of elements, or even their hiding or changing their form depending on the size of available space on the user’s screen. The front-end developer adjusts the size ranges with the help of CSS and for each element defines the behavior in these ranges. It will be desirable when the page is displayed on the phone, that the content is legible and all visible on the screen and the size of the buttons does not obscure other elements of the interface.
Imagine a situation when you switch from a web browser to a page where the font size can be compared with the size of an ant seen from a standing position. The vast majority of users leave such a page immediately because it is simply unusable. Adapting the user interface to the audience is the most important point of every project, don’t forget about it!

What are the questions to ask when you want to hire front-end developers?

Here are examples of questions that will surprise your candidates for front-end developers and weed out the weak ones (needless to say – we often ask them for our internal full-stack or front-end interviews at DevsData):

Q1. Please describe all the methods for converting a string into an integer in JavaScript?

• Number function
  var x = Number(“1234”)
• parseInt
  var x = parseInt(“1234”);
• parseFloat (Converting number with decimal points)
  var x = parseFloat(“1234.56”);
• Math.floor
  var x = Math(“1234.45”);
• Math.round
  var x = Math.round(“1000”)

Q2. What API documentation tool would you require from a Backend engineer when working on a project, why?

Swagger

• It is comprehensible for front-end developers, full-stack developers, and non-developers.
• It is easily adjustable, it can be successfully used for API testing and bug fixing.
• The same documentation can be used for accelerating various API-dependent processes.
• Provides a set of great tools for designing APIs and improving the work with web services: Swagger Editor, Swagger Codegen, Swagger UI, Swagger Inspector

ReDoc.ly

• • Extremely easy deployment
  • Server-Side Rendering ready
  • The widest OpenAPI v2.0 features support
  • OpenAPI 3.0 support
  • Neat interactive documentation for nested objects
  • Code samples support
  • Responsive three-panel design with menu/scrolling synchronization
  • Integrate API Introduction into the side menu
  • redoc-cli with ability to bundle your docs into zero-dependency HTML file

Q3. Have you heard about portals in React? What do they do?

A portal is a way to render an element outside of its component hierarchy, in a separate component.
When that event is rendered, events happening on it are managed by the React components hierarchy rather than by the hierarchy set by the DOM position of the element. Hence the name “portal”: an element sits somewhere in the DOM tree that’s outside of the normal React components tree, but the React component tree that includes it is still in charge. React offers an easy API to do this, ReactDOM.createPortal(), which accepts 2 arguments. The first is the element to render, the second is the DOM element where to render it. A classic use case for this is modal windows.

Q4. What are the “error boundaries” in React and why is it used?

Error boundaries are React components that catch JavaScript errors anywhere in their child component tree, log those errors, and display a fallback UI instead of the component tree that crashed. Error boundaries catch errors during rendering, in lifecycle methods, and in constructors of the whole tree below them.
The reason for using them is that before React 16, JavaScript errors inside components used to corrupt React’s internal state and cause it to emit cryptic errors on the next renders. These errors were always caused by an earlier error in the application code, but React did not provide a way to handle them gracefully in components, and could not recover from them.

For demanding clients

Wide range of technology services

Enterprise application
development

Mobile apps

Big Data and Data
Analytics

Tech recruitment
services

Learn more

Q5. What are the differences between Redux and Mobx?

Mobx is a testing library used to make scalable and simple state management with the help of TFRP (Transparent Functional Reactive Programming). It will help to make the state consistent. It follows the concept that everything that can be derived from the web application state, will be derived automatically. Redux is a javascript library for maintaining the application state management. Redux helps to develop the applications that behave consistently in all the environments and helps front-end developers and back-end developers to develop, test and debug the code easily.

Q6. What are filters in Vuejs?

Filters help with applying common text formatting. It is used in two places, mustache interpolations, and v-bind expressions. It mainly filters the data on the DOM level. So you get data that is still intact in the storage but is represented in the custom specified manner. It enhances the presentation of the view layer. The filters are also reusable. You can declare a filter globally and use it on any desirable component. It gives you the power to format your data at the view level.

Q7. Can you explain the difference between coding a website to be responsive versus using a mobile-first strategy?

Many people mistakenly think they are one and the same when they are entirely different. Coding a responsive website means that you start projecting to the desktop maximum resolution, and then scales down to the smallest screen. A mobile-first strategy is like designing a mobile app and adapting it neatly on tablets and desktop devices without too many modifications. Your layout is based on providing an excellent mobile UX.

Q8. What are the components props?

Every instance of a component has its own isolated scope. This means that you can’t directly reference parent data in a child component template. Data should be passed to child components using props. There are custom attributes you can register on a component. When a value is passed to the prop attribute, it becomes a property on that component instance.

Q9. What are pseudo-elements in CSS?

There is a keyword added to the selector. By pseudo-elements you can create or define elements that are not on the DOM. They allow styling one specific part of an element. They have no element type as far as the document language is concerned because they simply don’t exist in the DOM and can only be created using CSS. For example, it can be used to style the first letter or line of the element. Another function is inserting content before or after the content of the specified element.
Top-notch talent is a gem that only good interviewers can source.

Q10. Describe what steps your browser takes to render a pixel on your screen.

The answer to this question may be very broad, but the absolute minimum you should hear is the following.
There are five layers that “pixel” has to go through, and these are JavaScript code evaluation, style interpretation, layout structuring, painting, and composition. One after another, the JS code is executed in the JavaScript layer and that affects visual changes. Later, CSS styles are resolved and recalculated.
Then, when the browser knows what dimensions the element will have, the layout is drawn. Then the visual elements can be applied to the structure as layers. The last element is a composition in which when the page elements are ready, they can change their position.
In order to maintain maximum efficiency when browsing the site, the developer must remember which layer will be used for re-rendering.
When an element animation will affect the layout elements, the process will start with a layout recalculation. Using CSS properties only affects the composition, and that lets us save time and make our animation smoother.

Conclusions

Now it should be a piece of cake for you to hire front-end developers. Awesome front-end developers will not only have high-quality skills, attitude, and commitment but they will also make sure to acquire the necessary knowledge in the field to successfully deliver the project, either working full-time or part-time. Passionate front-end developers exude confidence in what they do. They are focused, goal-oriented and quick on their feet. Having such front-end developers on your team is an asset. They will help bring in more clients and ensure your company’s success in the industry.
If you need help to hire front-end developers, or hire a professional web developer, or want to develop a technology project, reach out to us at DevsData.
DevsData LLC is an IT software development and recruitment agency based in New York City and Europe. Equipped with Google-level engineers, we have the skills, experience, and resources to build complex, personalized systems to grow your financial business. Contact us today.