Front End Developer Interview Questions And Answers 2023
In the world of technology, a developer should be passionate about coding and efficient enough to convert the client’s needs into the application. In the front end developer interview questions, this type of eagerness is something the interviewer is looking into the candidates.
As we all are aware that the topmost IT companies are looking to hire front-end developers who are responsible to create and manage responsive and interactive applications for all the devices by keeping simplicity and customer convenience in mind.
Generally, many of the developers got confused and worried about which type of front end interview questions, they might be asked for. Here we have listed a few common questions which are going to help you in your interview.
Skillset Expected from a Front end Developer
- HTML and HTML5
- JavaScript
- JQuery
- Ajax
- CSS2 and CSS3 etc
Most Frequently Asked Front end Interview Questions
A promise means to the object which is responsible for producing a single value as the result in the upcoming future whether it is resolved or not.
Promises are used to manage asynchronous operations.
How to use the promise:
Let promise = new Promise(function(resolve, reject) {
// asynchronous call
});
Promise uses a callback function as the argument and that callback function takes 2 arguments: the first one is the resolve function or the other one is the reject function.
| Resetting | Normalizing |
|---|---|
| Resetting means to reset all styling from every element | Normalizing makes the built-in browser style more consistent. |
| Elements have the same font-size, same height, and no spacing at all. | Elements will appear bold, larger, etc in a consistent way. |
| In the end, elements will look similar. | Elements will look different in the end. |
NOTE: Normalizing is way much better than Resetting as there is no point in resetting all elements and styling them again.
| nth-of-type() | nth-child() |
|---|---|
| This is the selector that matches all the nth-child elements, of its parent in a particular type. | This is the selector that matches all the nth-child elements, of its parent in all the types. |
| It takes multiple elements that are used to describe the pattern for element matching. | It takes only one element that is used to describe the pattern for element matching. |
CDN is a Content Delivery Network and is a series of servers that are distributed all over the world and all are linked together.
Benefits Of Using CDN
- CDN files are placed on different domains. Apart from that, a single Content Delivery Network allows the browser to download four files at a single time.
- It boosts performance and saves money.
- It decreases the load on the server.
- CDN increases the number of concurrent users.
Domain prefetching is a process of resolving a website’s IP address before a user clicks on it.
Types of prefetching
- Link Prefetching
- DNS Prefetching
- Prerendering
This process allows the browser to perform the DNS lookups on a page in the background and at the same time the user can browse the current page. This minimizes latency as when the user clicks on the links they don't have to wait for DNS lookup.
| Unit Test | Functional Test |
|---|---|
| It tests the structure | It tests the functionality |
| This is performed by the developer when he codes. | This is performed by the Functional Tester. |
| The test happens at the time of coding. | The test happens after the development is complete. |
| This is a white box testing method. | This is a black-box testing method. |
Every HTML document consists of the following building blocks-
- Attribute: In HTML an attribute provides extra information about an element and that is applied within Start TAG. It contains two fields i.e. Name and Value
- Tags: Tags in HTML surround the content and add meaning to it and they are written between < and > brackets.
- Elements: In HTML file, everything written within tags are termed as HTML elements.
| S.no | Inline scripts | External scripts |
|---|---|---|
| 1. | It loaded in the same page so not necessary to trigger another request. | It gives better separation of concerns and maintainability. |
| 2. | These scripts executed immediately | External script is downloaded by the browser & stores it in the cache. |
| 3. | async and defer attributes did not use | async and defer attributes can be use |
| 4. | It is helpful when we are using a server side dynamic rendering | It can be used to load browser side code on demand & reduce overall download time and size. |
This method is used to converts JavaScript objects into strings. When sending data to a web server the data should be like string.
// Stringify a JavaScript object
var nObj = { "fname":"best", "mname":"interview", "lname":"question"};
var myJSONData = JSON.stringify(nObj);
document.getElementById("MyID").innerHTML = myJSONData ;
Three.js having various features that are given below:
- Effects and Animations
- Scenes and Cameras
- Data loaders and Shaders
- Geometry and Objects
- Debugging and Virtual reality
- Utilities and Materials
- Support etc
That’s it, hope you will find these front end engineer interview questions helpful. Though we are sure that these questions and answers are going to assist you in your interview since this list has been prepared by our experts. If you think we have missed out on anything important, please feel free to share your inputs in the comment section.