Complete hiring guide for JavaScript developers

Make sure the hiring of a JavaScript developer is foolproof with ourdetailed and completed hiring guide below. We explain every step of the hiring process with tips, relevant facts, and information for hiring managers and recruiters.

Marija Neshkoska

Marija Neshkoska

Complete hiring guide for JavaScript developers

JavaScript has always been popular in the IT industry because it allows developers to quickly and easily make websites that resemble apps, all with the help of one technology set and not too much hassle or time spent.

It is not the most straightforward task to choose a candidate out of many that applied.

Before continuing with the hiring process, you initially need to determine the type of JavaScript developer you need for your project. We will cover this, interviewing questions, and tips to avoid challenges and obstacles during the process—technical and non-technical skills, screening phases of the interview, and much more.

We also include helpful information directly from recruiters and developers, benefits and stats about JavaScript, and everything valuable to you to shorten the hiring period without sacrificing quality.

About JavaScript

JavaScript is an object-oriented, lightweight, dynamic programming language (scripting language) commonly used for creating web apps, web browser interactive effects, game development, and more.

Previously known as LiveScript, this programming language was first released back in 1995 as an integrated part within Netscape Navigator 2.0 (web browser), but later named LiveScript.

Despite being a programming language for web page use, JavaScript can also be perfectly intended and used for non-browser environments and uses. This dynamic language offers support for object construction based on prototypes, and its syntax resembles both Java and C++.

Stats about JavaScript

The salary of a JavaScript developer is, on average, $94,260 annually, with the highest pay being $109,796—a full stack position starts around $109K and above annually. Despite this fact, JavaScript is ranked lower than the most paid technologies.

The good thing about this programming language is that it is in high demand, but this fact does not correspond to the experts available. 75% of companies and employers actively need to find and hire a JavaScript developer.

The popularity of this language is outstanding, with 68.62% of surveyed developers preferring it the most for their work. This fact secures JS with first place on the popularity rank list, and a smaller percentage of 14.59% claimed they want to use JavaScript or implement it in their work.

JavaScript is a popular language with the following brands/companies:

  1. Microsoft
  2. Uber
  3. Netflix
  4. PayPal
  5. Groupon
  6. Google
  7. Facebook
  8. LinkedIn
  9. eBay
  10. Walmart
  11. IMDB
  12. Twitter
  13. Trello
  14. BBC

Interviewing a JavaScript developer

Helpful tips for a pre-screening interview

A critical segment of the whole finding and hiring process is to have a talent acquisition specialist conduct the pre-screening of the developers. These specialists have specific questions and assessment tasks that help evaluate a candidate's expertise.

Recruiters and talent acquisition specialists always inquire about past work experiences, in terms of years of working with JavaScript because this helps in determining the seniority level of the developer.

Another thing they check is the linguistic aspect or proficiency in English to check if there will be potential challenges in the daily communication between the client and developer.

Also, soft skills are crucial too, such as communicativeness, punctuality of the developer for the call, and the environment around the developer. Professional experience combined with appropriate appearance and attitude always bode well.

Technical skills of a JavaScript developer

The experienced JavaScript developer should have the following skills or extensive knowledge:

  • JavaScript
  • CSS
  • HTML
  • jQuery (JavaScript framework)
  • Asynchronous programming (Prototypes, Scope, Hosting, Coercion, etc.)
  • Cross-browser code writing
  • React JS (library)
  • Node JS (tool)
  • TypeScript

For this, we also asked Diamant Isufi, a software engineer in Proxify, to describe more about what else does the developer need to know, and he said:

“Besides the problem-solving skills, the developer must master all JS basics. Starting from how it works, when it is used and why, but also accurately describing simple data types, variables, functions, classes, constructor functions, and modularity.”

Non-technical skills of a JavaScript developer

The non-technical skills are a big chunk of the overall interview impression.

The recruiters know that not everything is solely expertise, technical knowledge, and experience. The essential minimum expectation is, of course, English language proficiency and being on time for the interview. Punctuality is a good indicator of the level of responsibility and respect the developer has for the recruiter, company, or client.

But, it doesn’t stop here. It is good, even strongly recommended, that the developer attends the call in a suitable environment/space. The environment needs to be neat, with enough lighting, good quality camera, and a headset (for a clear sound) if possible. The candidate should follow an appropriate dress code and be in a room without loudness or distractions.

Another thing for recruiters to focus on is the conversational skills of the candidate or how they handle the conversation flow. Listening without interruptions, talking clearly, or politely asking to repeat a question are plus points for the developer and add ‘points’ to their communicativeness aspect.

JavaScript interview questions to consider

Many questions are relevant for testing the expertise of the JS developer, but here are some suggestions that you could use during the interview:

  1. What is isNaN, and how is it used?
  2. Explain what is ‘negative infinity.’
  3. What are ‘global variables’?
  4. Explain the difference between SessionState and ViewState
  5. What are ‘looping structures’?
  6. Explain the meaning of ‘NULL’ in JS
  7. How is ‘Void (0)’ used?
  8. What is the ‘pop()’ method?
  9. State the difference between ‘.call()’ and ‘.apply()’
  10. How do ‘deferred scripts’ in JS work?

Essentials and assessment of a JavaScript developer

We mentioned above the skills and technical knowledge of a JavaScript developer; however, it’s good to sum up the overall essentials to look for:

  • Expertise in JavaScript, HTML, CSS and jquery
  • Knowledge of React JS, Node JS, and TypeScript
  • Knowledge of React and Redux
  • Good cross-browser coding skills
  • Asynchronous programming

But, also:

  • An analytical mindset that keeps up with fast-paced novelties
  • Knowledge of how various browsers or platforms function
  • Knowledge of Meteor (JS platform)
  • Version control experience
  • ES6 language features - (ECMAScript 6 - for standardizing JavaScript)

Diamant here further added:

“The developer also needs to know about ES7 (exponentiation generator). In general, I would also assess the problem-solving skills and ask about the frameworks and libraries of JS. After this, I would ask about their experience with Angular, Vue, and React. But, also overall, the technologies they need to know well are DOM (document object model), Node.js, NPM and Yarn, and NVM (node version manager), too.”

What distinguishes a great JavaScript developer from a good one?

There is always a fine line between excellent and (very) good developers, but once you see something that makes a difference, it can be crucial. In this case, the experienced and ideal JavaScript developer candidate must have substantial knowledge and experience with this programming language.

Also, they need to be able to work on desktop apps, hybrid mobile apps, games development, backend web apps, microservices, network services, as well as embedded apps with specific tools.

Additionally, a great developer candidate needs to know about ECMAScript frameworks and versions and use the best IDE (integrated development environment).

Possible challenges during the hiring of a JavaScript developer

There are challenges and certain obstacles during hiring processes, but it is important to recognize or anticipate them to avoid or resolve them as they appear.

One possible challenge is a scarcity of experts that genuinely have extensive in-depth knowledge and fit the criteria and requirements of the job position. Then further, there is the challenge of miscommunication regarding salaries or financial expectations that would correspond to the volume and complexity of the obligations.

In this context, if the demand for JavaScript devs on the market is high, there will always be competitors trying to ‘get’ the best developers for themselves. With this in mind, the whole recruiting process becomes more urgent and incredibly dynamic.

And of course, the recruitment process is costly by itself, so ideally, you’d need it to result in the best dev ‘ending up’ working for your company.

Why and when do you need to hire a JavaScript developer?

You can expect improvements in your business through the following aspects once you decide to hire a JavaScript dev:

  • ‘Bang for a buck’—JS is a fundamental programming language, and if the dev knows it, they probably also master other languages and technologies too.
  • Creating sable web servers and apps
  • Dynamically updated content
  • Easy control of videos, images, and multimedia elements
  • Emphasizing easily through animation
  • Game creation and development
  • Utilizing powerful frameworks—library of many structures for project particulars, with numerous features for quick and good quality development
  • Fullstack development—both frontend and backend are written easily
  • Simplicity of debugging and testing—identifying bugs quickly, codes are reviewed simple line by line
  • Creating cross-platform mobile and web apps
  • Excellent interfaces—creating captivating and visually gorgeous interfaces for the users, with drag and drop and more interesting and valuable features.
  • Concurrency—running more tasks at the same time, handling different operations, thus saving time overall
  • Cybersecurity

Diamant sums up the beneficial aspects of JS as:

“A JavaScript dev will be able to write codes for multiple platforms, and they are likely highly flexible to adapt to new frameworks and libraries that use JS, such as Angular, React, and Vue. Writing mobile and desktop apps is another notable benefit. Expertise in JavaScript is beneficial when a business is scaling, and demand for other platforms is raising.’

Benefits of JavaScript

  • Popularity—JavaScript is a popular programming language with many uses and implementations. As mentioned, a skilled dev can do related and other tasks not strictly confined to just JS.
  • Speed—JavaScript allows for fast work and development within the client-side browser, often without the need for external resources
  • Simplicity—Easy to learn and implement in the work
  • Creation of excellent interfaces
  • Multiple actions—JavaScript matches nicely with other programming languages and offers quality usage in other apps.
  • Open source projects access—the developer that needs to find assistance or guidance can easily do so
  • Simple syntax
  • Versatility
  • Not depending on a platform
  • Reduced server interactions

For the overall benefits and perks of working with JavaScript, Diamant also commented:

“I like this language's speed since it is not a compiling language but an interpreted one. It is prevalent on the web among all devs, so a massive community of experts offers quality information and access to needed resources, articles, courses, and more. And, the server-side rendering is another major benefit with JavaScript.”

Three steps to your perfect JavaScript developer

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    Tell us about your needs

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  • Step 2

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  • Step 3

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Find a JavaScript developer

7 things to know about JavaScript

JavaScript is a general-purpose programming (scripting) language. Together with HTML and CSS, JavaScript forms the backbone of frontend web development. It defines the behavior of dynamic web page elements done automatically in response to user actions. The JS code can be executed by JavaScript engines built into browsers or server-side JavaScript runtime environments.

  • What is JavaScript used for?

    JavaScript is used to create reactive web pages and dynamic web apps. Being run in the browser, JavaScript code enables web page interactivity, animated UI elements, data validation, and dynamic content. Being run on the backend, it powers real-time apps with event-driven architecture able to process millions of simultaneous connections.

  • What is Vanilla JavaScript?

    Plain JavaScript without any additional libraries or frameworks has jokingly been called ‘Vanilla JavaScript’. This term aims to attract developers’ attention to two common problems. Firstly, it reminds them that JS is powerful and self-sufficient in order to stop them from using heavy-weight frameworks for simple projects. Secondly, it encourages aspiring developers to learn the core of the language before they jump on learning any trendy frameworks to help them avoid knowledge gaps.

  • What are JavaScript frameworks?

    Unlike JavaScript libraries providing solutions to separate coding problems, JS frameworks predefine web application design as a whole. In addition to time-saving ready-made solutions, using frameworks brings structure and standardization to your project. The two most popular JS frameworks are Angular and Vue.js.

  • What is full-stack JavaScript?

    Full-stack development implies writing both frontend and backend parts of a web app with JavaScript. You can use JS full-stack development for fast prototyping to improve the speed and cost-efficiency of your MVP development cycle. In production, you can use full-stack JavaScript for creating isomorphic (universal) single-page apps that benefit from SEO-friendliness and UX fluidity.

  • What are the main features of JavaScript libraries?

    JavaScript has libraries which provide specific lines of code that can save time, improve performance, and reduce the number of potential vulnerabilities in the source code. The main features of JavaScript libraries complement the features of JavaScript itself. Since JS is predominantly considered a scripting language (apart from being a programming language), some of the features include: dynamic typing (as opposed to static typing), client-side validation, and asynchronous processing. In web development, JS frameworks can be used for building web pages, improving and adding new web components, and building user interfaces. For example, repetitive tasks such as animations or recurring interactive forms that appear in different places on your website could be automated by using a JS code snippet—without having to resort to writing the code from scratch for each of the interactive elements on the page.

  • JavaScript libraries you must know

    Some of the most popular JavaScript libraries you must be familiar with include: jQuery, React.js, and D3.js. JQuery is a JS library created to optimize HTML code, simplify DOM (Document Object Model) manipulation, and improve event handling. A shorter syntax, simpler code, and increased productivity are just a few of the benefits that come with using jQuery. React.js is a web component-based JS library that allows you to reuse, recycle and optimize the code across all of your web applications. It’s mostly used to create user interfaces or UI components, including nav bars, forms, page sections, buttons, and more. D3.js (Data Driven Documents) is another popular JS library with extremely robust and performance-reliant features. Some of these features include data visualization, HTML, CSS and SVG support, overhead reduction for enabling wider graphic complexity and dynamic behavior and multiple datasets for animation and interactivity—among others.

  • Compatible languages with JavaScript

    In functional programming, compatibility between different languages usually means whether or not one of the languages can compile to the other language. In our case, it refers to languages that can compile to JavaScript. Some of these languages are as follows: Scala.js, Typescript, and CoffeeScript. Scala.js is a compiler that translates Scala to JavaScript. Scala is a programming language created to bridge the gap between some of the concepts behind object-oriented languages and functional programming languages. Using Scala.js, you can start with an object-oriented approach and move toward a more functional approach depending on your project’s preferences and needs. TypeScript is considered a superset of JavaScript. All JavaScript programs are also valid TypeScript programs, but with static typing added into the fray. On a high level, TypeScript keeps the paradigm behind JavaScript intact, only introducing features to improve the robustness of the code. These features make coding in JavaScript more intuitive and pleasant. CoffeeScript highlights the good parts of JavaScript while introducing a cleaner syntax and preserving the semantics (logic) in place. This compiler has the distinctive feature of processing code written in the iterative style, where you primarily write comments and the code closely follows after the comments. You can run the compiler in any JavaScript framework (or environment), or in the web browser itself.

  • Is JavaScript still widely used?

    JavaScript is one of the most commonly used scripting languages today, both on the client-side and server-side of things. The popularity of JavaScript has significantly increased since the release of Node.js in 2009. Node.js is a JavaScript framework that empowers developers to use a single programming language for the entirety of their development process, instead of relying on multiple languages. In simple terms, you can leverage your preferred JavaScript frameworks to send HTTP requests, create dynamic user experiences and generate interactive content.

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  • How does the vetting process work?

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