What does a JavaScript developer do?

Millions of web pages are created on the internet with the help of JavaScript programming language. It is used to write code for programs, scripts, applications, services, and websites — connecting the front end (visual part) with the back end. As a rule, JS developers are supposed to connect with other front-end engineers specializing in layouts, CSS, and visual design. The main focus of JS coders, though, is user experience. They ensure an instant and consistent response to user actions, efficient getting of data from the servers, and dynamic page updating. JavaScript professionals work part-time and full-time, cooperating with international and local organizations — or choosing a remote, part-time path and seeking jobs on bidding and vetting platforms.

Is JavaScript a good choice for your career?

Everyone deciding which programming language to learn will inevitably ponder over a thousand questions. Shall I start with the easiest ones? With the most relevant to my fields of interest? Which languages have the best learning curve? Which of them is the most useful? Python or Java? Or maybe, JavaScript? With so many frameworks and libraries with ready-to-use code, is it necessary to spend time on JS? The recent Stackoverflow survey shows JS has been the most popular language for 10 years. Even though it was originally developed as a client-side language, now, thanks to Node.js, React Native, and Ionics, it has also made its way to the server side. So, even if you don’t plan to start a full-scale tech career, proficiency in JS never hurts (and helps build web pages from scratch, for that matter). In addition, JS is extremely versatile: with the help of Node.js, you can build the back end, and Angular will assist you in the front-end matters.

What every JavaScript developer should know?

According to the StackOverflow 2021 survey, JavaScript remains the #1 programming language in the world and is widely employed in 95% of all websites. You should know many things to blossom and flourish in the JS universe. We’re, of course, not going to list all of them — however, it would be nice and handy to elaborate on the main concepts that help both noob coders and apt engineers in their daily programming life. Scope . The concept of scope is linked to the variable access and the question of which variables you have access to while the code runs. The scope can be imagined as a virtual box with variables, functions, and objects. This box of scope has boundaries and restrictions that allow or block your access to the necessary elements. Local scope is everything within certain boundaries, and global scope is outside. So, if a variable is local, you don’t have access to it globally, and vice versa. IIFE — Immediately Invoked Function Expression. It’s a function evoked and executed right after it was defined. The main point of the use of IIFE is immediate execution and data privacy enhancement. Hoisting. In JS, one can call a function before its defining — precisely thanks to hoisting. By hoisting, we understand that the JS interpreter always moves the variables and functions to the top of the current scope before code execution. Closure . A closure is a function inside another function and has access to the variable used in the outer function. Watch the magic: the outer function has no access to the inner function variables, but thanks to closures, the inner one has access to the outer function's variables. Callback . It’s a function passed to another function as a parameter (the latter function must wait for the former to execute). Callbacks are used for maintaining synchronous capabilities. Promise . A promise is a salvation from the so-called callback hell occurring when the recursive callback structure (a callback inside a callback, etc.). A promise is an object that may produce a single value in the future — or a reason why the value isn’t resolved. Async&await . One more way to perform asynchronous operations more synchronously. It can be used to perform the Rest API request where you want data to be fully downloaded before transposing it to the view.

What are the basic data types of JavaScript?

Six main data types can be grouped into three categories. In the primitive (or primary) category, we have String, Number, and Boolean. The composite category consists of Object, Array, and Function types. Undefined and Null types belong to the Special category. The String type represents textual data (in single or double quotes). The Number data type represents positive and negative numbers with or without decimals (written with the help of decimal notation). The Boolean type holds only two values — True and False. The Undefined type consists of one value — Undefined (for declared and unassigned variables). The Null data type has only one value, and that’s null. It doesn’t mean empty string or zero, it means nothing. The Object type allows storing collections of data represented as key-value pairs. The Array type is used for storing many objects in a single variable. The Function type is a callable object for code block execution.

Is JavaScript coding?

To put it briefly for all who need the short answers — yes, it’s coding. JavaScript is a programming language that implements complex features on web pages, both on the front and back. When you see a non-static web page (i.e., a page not only showing you some pictures or text statically but also displaying animations, interactive elements, and video jukeboxes), there’s a 100% probability that JavaScript was somehow involved in its creation. Two other elements that were probably used are HTML (for structuring elements on the page) and CSS (for visuals and styling). In addition, JS can store values inside variables, perform textual operations, and run code chunks in response to some events on the page (and many more!)

JavaScript Developer Job Description Template

This comprehensive template of the job description for a JavaScript developer will help you compose job descriptions that will lure the most qualified and talented web engineers to your company, ensuring its flourishment and steady growth. You can use its elements for posting to career pages or online job boards where programmers with expert knowledge of JavaScript will see them and, hopefully, come to your startup.

hire a Javascript pro!

How to write a JavaScript developer job description

After defining your desired skill set for the JavaScript professional, write a clear job description. For you, a well-composed job description is a perfect way to move your needs to the front so that the relevant top talents can send you their CV with the speed of lightning.

What are the core elements of a JavaScript developer job description? To put it briefly, a concise yet comprehensive description consists of the following parts:

Summary

In this section, you should focus on covering the basic questions a potential candidate might have to begin with:

Why do you want a JS engineer in your company?
How does this role fit into your working team?
Why is your company unique?
What are the working conditions in your company?

Requirements

Next, you goal is to filter out candidates that don’t fit the portrait of a ideal hire for you by explaining in great detail your expectations. Try and answer the following question:

What tech skills do you require for this role?
Which soft skills are preferable for this role?
What are the beneficial experiences for this role?

Responsibilities

Clarify the key deliverables for the JavaScript developer role and describe the ideal candidate’s daily routine.

Benefits

The candidate should get all the available information about bonuses, compensations, possible training, and extra perks.

Company descriptionAdd a short description of your company, describe the work culture, and highlight the unique selling points of working with you. Pitch yourself to the potential candidates.

Example:

Lemon.io is a freelance marketplace with over 1000 vetted developers from 26 European countries looking for their next big project at Western startups. Before the COVID pandemic, it was based in Kyiv, Ukraine. As of now, its 60+ employees operate from all over the world.

The company was founded in 2015 in Kyiv by Anvar Azizov, Vasyl Dzesa, and Alexander Volodarsky as a small startup called Coding Ninjas. From the start, it began working as “Uber for developers”: a small pool of pre-vetted specialists closed minor, mainly WordPress-related tasks. Subsequently, more requests for full-time specialists appeared, and the company changed its working mode.

In 2020, Coding Ninjas went through radical changes and a complete rebranding. It emerged as Lemon.io, a full-fledged marketplace of vetted developers with Sales, Matching, Recruiting, Talent Acquisition, Marketing, and Customer Success departments.

What makes us different?

We’ll find you a team that respects you. No time-trackers or any micromanagement stuff.
Our engineers earn $5k — $10k / month. We’ve already paid out over $10M.
Choose your schedule. We have both full- and part-time projects.
No project managers in the middle — only direct communications with clients, most of whom have a technical background.
Our customer success team provides life support to help you resolve anything.
You don’t have to look for clients and negotiate anymore: just do what you do best and leave us the rest.

javascript experts here!

JavaScript developer job responsibilities

Here’s what a skilled JavaScript developer job responsibilities list can look like.

As a JavaScript specialist at our company, you will:

Design and develop JavaScript applications;
Write reusable and testable code components with the end users in mind;
Write high-performance code (performance is our key to success);
Cooperate with QA and UI/UX departments to ensure maximum user satisfaction and software reliability;
Compose a set of unit tests for your application to get convinced that everything is working;
Write extensive documentation on each element of the application;

JavaScript developer requirements and qualifications

Your list of JS developer requirements and qualifications can look like this sample here. However, remember that you should add, cut, or change the points on the list to meet your specific expectations:

3+ years of software development experience;
Strong knowledge of JavaScript (Core, DOM APIs);
3+ years of experience with Node.js;
Experience with front-end JavaScript frameworks and libraries (React.js preferably);
Understanding of and practical experience with SOLID principles and GOF patterns;
Understanding of CI principles;
Experience with Typescript and React Native would be a plus;
Familiarity with browser performance and behavior;
Understanding of the working principles of JavaScript module loaders like Require.js and AMD;
Basic knowledge in AJAX, partial page updates, and asynchronous request handling;
Professional certifications.

Benefits and perks for JavaScript developers

The brightest and most euphoric section of the job description. Describe all the benefits your company offers. Don’t forget anything (better ask the HR specialists for details). How will you make candidates happy?

Example:

Career&growth opportunities;
Proper and regular compensation;
Medical insurance;
Supportive team;
Free psychotherapy.

Looking for a JavaScript dev? Check these out:

Software Engineer with 10 years experience specializing in Javascript; usually prefers to build UI complex websites but also feels comfortable working on backend development.

Salih is an ideal middle developer - he can cope with a wide range of tasks and conduct research to dig to the root. He enjoys solving problems, boosting his dopamine level when finding solutions.

Started coding in 2017 and picked Node as his one and only; Nikita strives to achieve excellent results in any project he joins, while also being ready to grow rapidly in a startup environment.

Denys is a senior front-end developer with 8 years of experience who has completed a project through our platform. Proficient in React ecosystem, fluent in Javascript & Typescript.

Need some more? Read our FAQ!

What does a JavaScript developer do?
Millions of web pages are created on the internet with the help of JavaScript programming language. It is used to write code for programs, scripts, applications, services, and websites — connecting the front end (visual part) with the back end. As a rule, JS developers are supposed to connect with other front-end engineers specializing in layouts, CSS, and visual design. The main focus of JS coders, though, is user experience. They ensure an instant and consistent response to user actions, efficient getting of data from the servers, and dynamic page updating. JavaScript professionals work part-time and full-time, cooperating with international and local organizations — or choosing a remote, part-time path and seeking jobs on bidding and vetting platforms.
Is JavaScript a good choice for your career?
Everyone deciding which programming language to learn will inevitably ponder over a thousand questions. Shall I start with the easiest ones? With the most relevant to my fields of interest? Which languages have the best learning curve? Which of them is the most useful? Python or Java? Or maybe, JavaScript?
With so many frameworks and libraries with ready-to-use code, is it necessary to spend time on JS? The recent Stackoverflow survey shows JS has been the most popular language for 10 years. Even though it was originally developed as a client-side language, now, thanks to Node.js, React Native, and Ionics, it has also made its way to the server side. So, even if you don’t plan to start a full-scale tech career, proficiency in JS never hurts (and helps build web pages from scratch, for that matter). In addition, JS is extremely versatile: with the help of Node.js, you can build the back end, and Angular will assist you in the front-end matters.
What every JavaScript developer should know?
According to the StackOverflow 2021 survey, JavaScript remains the #1 programming language in the world and is widely employed in 95% of all websites. You should know many things to blossom and flourish in the JS universe. We’re, of course, not going to list all of them — however, it would be nice and handy to elaborate on the main concepts that help both noob coders and apt engineers in their daily programming life.
Scope. The concept of scope is linked to the variable access and the question of which variables you have access to while the code runs. The scope can be imagined as a virtual box with variables, functions, and objects. This box of scope has boundaries and restrictions that allow or block your access to the necessary elements. Local scope is everything within certain boundaries, and global scope is outside. So, if a variable is local, you don’t have access to it globally, and vice versa.
IIFE — Immediately Invoked Function Expression. It’s a function evoked and executed right after it was defined. The main point of the use of IIFE is immediate execution and data privacy enhancement.
Hoisting. In JS, one can call a function before its defining — precisely thanks to hoisting. By hoisting, we understand that the JS interpreter always moves the variables and functions to the top of the current scope before code execution.
Closure. A closure is a function inside another function and has access to the variable used in the outer function. Watch the magic: the outer function has no access to the inner function variables, but thanks to closures, the inner one has access to the outer function’s variables.
Callback. It’s a function passed to another function as a parameter (the latter function must wait for the former to execute). Callbacks are used for maintaining synchronous capabilities.
Promise. A promise is a salvation from the so-called callback hell occurring when the recursive callback structure (a callback inside a callback, etc.). A promise is an object that may produce a single value in the future — or a reason why the value isn’t resolved.
Async&await. One more way to perform asynchronous operations more synchronously. It can be used to perform the Rest API request where you want data to be fully downloaded before transposing it to the view.
What are the basic data types of JavaScript?
Six main data types can be grouped into three categories. In the primitive (or primary) category, we have String, Number, and Boolean. The composite category consists of Object, Array, and Function types. Undefined and Null types belong to the Special category.
The String type represents textual data (in single or double quotes).
The Number data type represents positive and negative numbers with or without decimals (written with the help of decimal notation).
The Boolean type holds only two values — True and False.
The Undefined type consists of one value — Undefined (for declared and unassigned variables).
The Null data type has only one value, and that’s null. It doesn’t mean empty string or zero, it means nothing.
The Object type allows storing collections of data represented as key-value pairs.
The Array type is used for storing many objects in a single variable.
The Function type is a callable object for code block execution.
Is JavaScript coding?
To put it briefly for all who need the short answers — yes, it’s coding.
JavaScript is a programming language that implements complex features on web pages, both on the front and back. When you see a non-static web page (i.e., a page not only showing you some pictures or text statically but also displaying animations, interactive elements, and video jukeboxes), there’s a 100% probability that JavaScript was somehow involved in its creation. Two other elements that were probably used are HTML (for structuring elements on the page) and CSS (for visuals and styling).
In addition, JS can store values inside variables, perform textual operations, and run code chunks in response to some events on the page (and many more!)

Explore our stacks and pages: Styled-components, Swinject, .NET + C#, NUnit, SignaIR