207 docs tagged with "interview questions"

The abstract factory pattern is a creational design pattern that produces families of related objects without specifying their concrete classes.

Adapter is a structural design pattern that facilitates the collaboration of objects having conflicting interfaces.

Alternation is the term in regular expression that is a simple “OR”. In a regular expression an “OR” is denoted with a vertical line character. Questions

Anchors in regex are used to match the start and end of a string. They are used to match the start and end of a string.

ArrayBuffer, Binary Arrays are used to store binary data. They are used in the browser to store images, videos, sounds, etc. They are also used in the browser to store binary data.

What is the definition of an arrow function? Arrow functions are a concise way to write functions in JavaScript. Frontend developer interview questions answers.

Async Iteration and Generators are a way to create iterators in JavaScript. What are some popular applications for asynchronous iteration in JavaScript?

Async/Await is a way to handle asynchronous operations in a synchronous manner. An async function is a function declared with the async keyword. Questions

Attributes / Properties are properties of an HTML tag. They are used to add information to the tag and to control the behavior of the tag. Interview Questions

Automated testing is a key part of the JavaScript ecosystem. It is a process that allows you to test your code without having to write a lot of code.

A backreference in a regular expression identifies a previously matched group and looks for the same text again. Regular Expressions Interview Questions

Basic JavaScript Questions | Frontend Developer Interview Questions - What is JavaScript? JavaScript is an interpreted language, V8 compiles it to machine code.

Bezier Curve is used to draw curves in JavaScript. Bezier curves are used in computer graphics to draw shapes. - JavaScript Interview Questions and Answers.

BigInt is a new type of number in JavaScript. They are used to represent integers that are bigger than the max safe integer. - Frontend Interview Questions

Binary Data / Files - The binary data files are used to store the data in the form of bytes.

Blob Data is a built-in object that allows you to create a Blob object. It is used in the browser to create a Blob object from an array of bytes.

The bridge pattern is a structural pattern used in web development to decouple an abstraction from its implementation so that the two can vary independently.

Several events automatically cause the browser to do particular actions by default. These are called default browser actions. Interview Questions

Browser Environment Specification is a set of specifications that describe the environment in which a web browser runs. - JavaScript Interview Questions

Browser Events are the events that occur in the browser. They are used to interact with the browser. - JavaScript Interview Questions & Answers

How to interact with the browser window. How does the alert function work? How many arguments does the prompt function accept? Frontend Interview Questions

Bubbling and Capturing Events in JavaScript - The bubbling-up principle is self-explanatory based on its name. - JavaScript Interview Questions & Answers

It lets you build complex objects step by step. The builder pattern allows you to produce different object types and representations using the same builder code.

Callbacks are a way to pass functions as arguments to other functions, and to return them as the result of the function. Pass your next frontend phone interview

A capturing group is a pattern enclosed in parentheses. It two affects consisting of getting part of match as a separate or isolated item in an array of items.

Catastrophic backtracking is a condition that can occur if you are checking a (usually long) string against a complex regular expression.

The chain of responsibility pattern allows a client request to be received by multiple objects. JavaScript Frontend Phone Interview Question

Character Classes are used to match text against regular expressions. A character class is a special notation that matches any symbol from a set. Questions

Class Checking instanceof is the syntax for checking if an object is an instance of a class. The instanceof allows us to check if an object belongs to a class.

Class Inheritance in JavaScript is a syntax for creating a class in JavaScript. What is the extends keyword used in JavaScript classes? Interview Questions

Clickjacking Attacks is the process of a malicious site trying to trick a user into clicking on a link that is on another site.

The key to reducing unnecessary comments in your code is to write self-descriptive code. The way to achieve this is to replace a chunk of code with a function.

Define what a statement is in JavaScript code structure? Can semi-colons be omitted in JavaScript? | Frontend Developer Interview Questions & Answers

Coding style is a set of rules for writing code. This guide helps you to understand coding styles and how to follow them in JavaScript. - Interview Responses

Command Pattern is a behavioral JS design pattern that aims to encapsulate actions or operations as objects. JavaScript Frontend Phone Interview Questions

Learn how to compare values in JavaScript. All JavaScript comparisons return a true or false Boolean value. | Frontend Developer Interview Questions & Answers

The composite is a structural pattern that composes objects into trees and then works with these structures as if they were individual objects.

Learn how to use conditional branching in JavaScript. Can you execute more than one statement in an if statement? | Frontend Interview Questions & Answers

The constructor pattern is a class or function-based pattern used in the creation of specific types of objects. JavaScript interview questions and answers.

Cookies - document.cookie - JavaScript Interview Questions and Answers Cookies are tiny data strings saved directly in the browser. Frontend Developer Questions

Cross-Origin Requests uses the CORS (Cross-Origin Resource Sharing) protocol to allow web applications to access resources from other domains.

Cross-Window Communication in JavaScript is a way to communicate between different windows. - JavaScript Interview Questions & Answers

CSS-Animations is used to animate elements. CSS animations make it possible to do simple animations without JavaScript. - JavaScript Interview Questions

Currying is a technique that allows us to create functions that take multiple arguments. JavaScript Interview Questions & Answers

Custom Elements in JavaScript web development are used to create reusable components. - JavaScript Interview Questions and Answers

Custom Error Handling in JavaScript is a good way to handle errors in your code. How would you extend beyond the initial inheritance of the Error object?

There are eight basic data types in JavaScript including Number, String, Boolean, BigInt, Null, Undefined, Object, and Symbol. JS Frontend Interview Questions

JavaScript dates and times are represented by the Date object. Date objects represent a single moment in time in a platform-independent format. Interview Answer

Explain what debugging is in JavaScript development? Debugging is finding and fixing errors within a script, module, or application with tools in Chrome.

The decorator pattern is a JS structural pattern that promotes code reusability. They, like Mixins, can be viewed as a replacement for object sub-classing.

The difference of call and apply is what they accept as args; call expects all parameters to passed individually, whereas apply expects an array of parameters.

Pattern-ity Testing, Proto-Patterns & The Rule Of Three - A pattern that has not yet passed "pattern"-ity tests is called a proto-pattern.

Destructuring assignment is a JavaScript expression that allows us to extract data from arrays, or object properties, and assign them to variables. Interviewer

What is the developer console used for in JavaScript development? A developer console is a tool that allows you to interact with the JavaScript engine.

Dispatching Custom Events in JavaScript - The Event() constructor creates a new Event. - JavaScript Interview Questions & Answers

DOM Tree is a tree structure that represents the structure of the HTML DOM. - JavaScript Interview Questions & Answers

Dynamic Imports in JavaScript ES6 Modules - We can implement dynamic imports by using the import expression. Frontend Developer Interview Questions

Element Size / Scrolling in the DOM is a topic that is covered in this article. - JavaScript Interview Questions & Answers

Error Handling in JavaScript is a very important part of any web application. The try…catch construct has two main blocks, try and then catch blocks. Questions

Promises Chaining is a way to chain promises together. How is error handling achieved with promises in JavaScript? Pass Your Next Frontend Interview

To match a character having special meaning in regex, you need to use a escape sequence prefix with a backslash (\). Regular Expressions Interview Questions

Event Delegation is a technique that allows you to listen for events on a parent element; then delegate the event to its children. Interview Questions & Answers

Event loop - Microtasks / Macrotasks in JavaScript is a way to run code asynchronously. The event loop is a programming construct - Interview Questions & Answer

JavaScript Export and Import Modules interview questions and answers. We can label any declaration as exported by placing export before it. Interview Answers

Extending built-in classes is a process of creating a new class that inherits from an existing class. Frontend Developer Phone Interview Questions

Learn how to use External Scripts in JavaScript. How do you access external script files in JavaScript development? | Frontend Developer Interview Questions

The Façade design pattern creates an interface that protects clients from complex functionality in one or more subsystems.

The factory pattern offers an interface for producing objects in a superclass while allowing subclasses to change the type of objects created.

Fetch - Abort is used to abort a fetch request. In JavaScript, we can use the fetch method to abort a request.

Fetch - Download Progress is used to track the progress of a download. How can we track download progress in JavaScript? JavaScript Interview Questions

Fetch API is used to make network requests. It is used to make GET, POST, PUT, DELETE, and PATCH network requests. JavaScript Frontend Phone Interview Questions

Fetch Requests are used to make requests to the server. Fetch is a modern browser-based alternative to XMLHttpRequest. JavaScript Interview Questions and Answer

JavaScript File and FileReader objects are used to read and write files. FileReader objects are used to read the contents of files.

Can you explain the flyweight design pattern? The Flyweight pattern gets classified as a Structural design pattern. JavaScript interview questions.

Focusing - focus/blur in JavaScript is an event that occurs when a user focuses on an element. - JavaScript Interview Questions & Answers

Form Events in JavaScript are events that occur when a user interacts with a form. The change event triggers when the element has finished changing. - JavaScript Interview Questions & Answers

Form Properties / Methods in JavaScript are properties and methods that are associated with a form element. - JavaScript Interview Questions & Answers

Form Submit / Events in JavaScript are events that occur when a user interacts with a form. - JavaScript Interview Questions & Answers

FormData Object is used to send data to a server. It is used to send the data in the form of key-value pairs. JavaScript Frontend Phone Interview Questions

Forms / Controls

Frames / Windows

Function Binding is a very common interview question. Binding is a process in which a function is bound to a value.

Function expressions are a way to create a function on the fly. Describe a function expression’s code structure and behavior? Frontend Interview Questions

All functions in JavaScript are objects. The concept of functions as callable "action objects" is an excellent approach to thinking about them.

Function Prototype in JavaScript is a property of the function object. It is used to store the function's properties and methods. Interview Answers

The 7 types of functions include the function declaration, expressions, arrow function, shorthand methods, generators, constructors, and JS built-in methods.

Garbage collection is a process that removes unused objects from memory. The central concept of memory management in JavaScript is reachability. Interview

JavaScript generators are a way to create iterators. What is the distinction between a generator and a regular function? Frontend Developer Interview Answers

By default, quantifiers are Greedy. Greedy quantifiers try to match the longest text that matches given pattern. Regular Expressions Interview Questions

The Script tag is used to load JavaScript files. We can use the script tag to insert JS into HTML or import scripts from external sources. Interview Questions

IndexedDB is a database that is stored in the browser. It is used to store data in the browser. | JavaScript Frontend Phone Interview Questions

The interpreter pattern offers a scripting language that allows end users (developers) to customize their solutions.

A design pattern is reusable code that acts as a solution to recurring problems. The three groups are creational, structural, and behavioral design patterns.

What are iterables in JavaScript? Iterable Types are objects that can be iterated over. Iterable objects are a subset of arrays. Interview Answers

An iterator is a behavioral design pattern that allows you to traverse elements of a collection without revealing its underlying representation.

JavaScript Animations are used to animate elements in JavaScript. The requestAnimationFrame delivers higher-quality animation. - JavaScript Interview Answers

Explain the function and syntax of the array splice() method? How do negative array indexes work? Why can’t you use a return statement in a forEach loop?

What is an array? Arrays are a collection of indexed values that can be accessed by a numerical index. We use arrays to store an collection of values. Frontend

Arrow Functions are a very common interview question. Arrow functions are a concise way to write anonymous functions.

Basic Class Syntax in JavaScript is a syntax for creating a class in JavaScript. Classes are a template for creating objects.

An IDE is a development environment (code editor) that allows developers to load, save, edit, manage, and delete projects or files written in JavaScript.

Professional JavaScript developers typically refer to ECMA-262 specifications, MDN JavaScript references, and compatibility tables like CanIUse.com.

JavaScript Mixins is a syntax for creating a mixin in JavaScript. A mixin is a class that is designed to be used as a mixin. Frontend Interview Questions

Object Methods are methods that are attached to objects. They can be called on objects. Frontend Phone Interview Questions and Answers

JavaScript Objects are a collection of key-value pairs. They are used to store data. String, Symbol, BigInt, Boolean, undefined, number, and null data types.

Explain what is JSON? What are the methods available in JSON? What are the differences between JSON and JavaScript? How can we use JSON methods in JavaScript?

Keyboard Events in JavaScript are events that occur when a user interacts with a keyboard. They are triggered by the user's keyboard. - JavaScript Interview Questions & Answers

LocalStorage / sessionStorage in JavaScript is used to store data in the browser. It is used to store data in the browser. JavaScript Frontend Questions

Logical operators are used to combine conditional statements. Logical operators can be applied to values of any type; they are not limited to a Boolean type.

Long Polling in JavaScript is used to check for changes in the server. Long polling is the simplest way of having a persistent connection with the server.

The lookahead approach involves in catching a match based on a proceeding character or digit.

What is the difference between Map and Object in JavaScript? Map and Set are not primitive data types in JavaScript. They are objects. Interview Answers

How to use basic mathematical operators in JavaScript. The basic mathematical operations include addition, subtraction, multiplication, division, remainder or modulo, and exponentiation.

The mediator pattern is a structural pattern that enables one item to alert another group of objects when an event or action occurs. Interview Questions

The memento pattern is a behavioral pattern that allows you to save and restore an object's previous state without revealing its implementation details.

Methods of Primitives are functions that are attached to primitive values. What are the 7 primitive data types? Interview Questions and Answers for developers.

The Microtask Queue is a queue of tasks that are executed as soon as possible after the current task has finished. Can you explain Microtasks

A mixin is a JavaScript object that contains methods that other classes can use without inheriting from it. JavaScript Frontend Phone Interview Questions

Modern Markup in JavaScript - When working with modules, we use the script type attribute in Modern JavaScript. Frontend Developer Interview Questions n Answers

JavaScript allows us to modify the HTML document by using the Document Object Model (DOM). - JavaScript Interview Questions & Answers

Another popular JavaScript design pattern for keeping our code tidy, segregated, and organized is the Module Pattern.

JavaScript Modules are a way to organize code into logical units. Modules are used to break down large projects into smaller pieces. Interview Questions

Mouse Events in JavaScript are events that occur when a user interacts with a mouse. They are triggered by the user. - JavaScript Interview Questions & Answers

Moving the Mouse in JavaScript is a technique that allows you to move the mouse pointer. This is useful for interacting with the mouse. - JavaScript Interview Questions & Answers

The m flag is used to specify that a multiline input string should be treated as multiple lines. Regular Expressions Interview Questions

Mutation Observer in JavaScript is a JavaScript API that allows you to observe changes in the DOM. - JavaScript Interview Questions & Answers

Native Prototypes in JavaScript are a property of the Object.prototype object. It is used to store the Object's properties and methods.

Ninja Code - Are one-letter variables a practical idea to use in programming? No, they can confuse a team and make it harder to debug. Don't be a Coding Ninja!

Node Properties are properties of the Node object. They are used to access the Node object. - JavaScript Interview Questions & Answers

Learn how to use the nullish coalescing operator in JavaScript. Explain how the nullish coalescing operator works? Frontend Developer Interview Questions

What are the two primitive number data types in JavaScript? In JavaScript, the two number data types include numbers and BigInts. Frontend Developer Interview

Object References and Copying | JavaScript Frontend Phone Interview

The object to primitive conversion is a JavaScript operator that converts an object to a primitive value. All objects are true in a Boolean context. Interview

Object.keys, values, entries are used to get the keys, values, and entries from an object. They are used to iterate over the object. Frontend Interview Answers

Objects the Basics

The observer pattern allows you to define a subscription mechanism that will notify multiple objects about any events on the object we attempt to observe.

The optional chaining operator (?.) is a JavaScript operator that is used to access properties and methods of an object. Pass your next frontend phone interview

Page Lifecycle in JavaScript is a set of events that occur when a page is loaded. They are triggered by the browser. - JavaScript Interview Questions & Answers

Patterns and Flags are used to match text against regular expressions. They are used to match text against regular expressions. Interview Questions

Pointer Events in JavaScript are events that occur when a user interacts with a pointer. They are triggered by the user's pointer. - JavaScript Interview Questions & Answers

Popups / Window Methods in JavaScript is a way to open a new window or a new tab. - JavaScript Interview Questions & Answers

Private, Protected Props / Methods are a way to create properties and methods that are only accessible within the class. Frontend Developer Interview Questions

Promise API is the standard API for promises in JavaScript. What are the Promise class's six static methods? Pass Your Next Frontend Phone Interview Questions

JavaScript Promises are a way to handle asynchronous operations in JavaScript.

Promises Chaining is a way to chain promises together. Chaining promises is a process of chaining subscribers of the initial promise. Interview Questions

Promisification is a way to convert a callback-based function into a promise-based function. Promisification is a long word for a simple transformation.

Property Flags / Descriptors interview questions. Object property attributes/flags include writeable, enumerable, and configurable flags. Interview Answers

Property Getters & Setters is a very common interview question. Property Getters & Setters is a process in which a property is defined as a getter and setter.

Prototypal Inheritance is a very common interview question. Prototypal Inheritance is a process in which an object inherits properties from another object.

The prototype is a creational design pattern that allows you to replicate existing objects without relying on their classes. Interview Questions and Answers

Prototype Methods in JavaScript are a property of the prototype object. It is used to store the function's properties and methods. Interview Questions

JavaScript Proxy and Reflect is a way to create a proxy object that can be used to intercept and change the behavior of an object. Frontend Interview Questions.

A proxy is a structural pattern that lets you provide a substitute for another object. The Proxy Pattern acts as a placeholder for another object.

A quantifier is used to find the exact count in a sequence of digits. JavasScript Interview Questions and Answers

Recursion & Stack is a very common interview question.

Reference Type is an internal type of the language in JavaScript. They are used to store data. - JavaScript Interview Questions & Answers

Regex / String Methods - The following are the methods available in the regular expression and string objects. Regular Expressions Interview Questions

In simple terms, a range in a regular is denoted or expression inside of square brackets. For instance, [a-z] denotes a range of lowercase letters.

Regex Sticky Flag - The flag y allows us to perform the search at the given position in the source string. There is a performance gain when using flag y.

Resource Loading in JavaScript is a way to load external resources asynchronously. - JavaScript Interview Questions & Answers

Rest Parameters / Spread Syntax is a very common interview question.

Resumable File Uploads is used to upload large files in chunks. We may use XMLHttpRequest instead of fetch. Frontend Developer JavaScript Interview Questions

The basic tenet of the Revealing Module pattern is that all functions and variables should be hidden unless explicitly revealed.

Scheduling / Timing - setTimeout / setInterval is a very common interview question. There are two commonly used methods for scheduling calls in JavaScript.

Scripts - Async/Defer in JavaScript is a way to load JavaScript files asynchronously. - JavaScript Interview Questions & Answers

Scrolling Events in JavaScript are events that occur when a user interacts with a scrollbar. They are triggered by the user's scrollbar. - JavaScript Interview Questions & Answers

Searching the DOM is the process of finding an element in the DOM tree. - JavaScript interview questions & answers

Selection and Range in JavaScript is a JavaScript API that allows you to select text in a document. - JavaScript Interview Questions & Answers

Server Sent Events is used to send data to the client. The Server-Sent Events specification describes the built-in class EventSource. - Interview Questions

Shadow DOM is used to create a virtual DOM tree that is not connected to the real DOM tree. Encapsulation gets provided via the Shadow DOM.

Shadow DOM / Events are used to add event listeners to elements in Shadow DOM. They are used to add event listeners to elements in Shadow DOM.

Shadow DOM Slots is used to compose elements in Shadow DOM. It is used to compose elements in Shadow DOM. JavaScript Frontend Phone Interview Questions

Shadow DOM Styling is used to style elements in Shadow DOM. It is used to style elements in Shadow DOM. It is used to style elements in Shadow DOM.

Singleton is a creational design pattern that lets you ensure that a class has only one instance, while providing a global access point to this instance.

State is a behavioral design pattern that lets an object alter its behavior when its internal state changes. It appears as if the object changed its class.

Static Properties / Methods are a way to create properties and methods that are shared by all instances of a class. JavaScript Frontend Interview Questions

The strategy is a behavioral pattern that allows an object to shift its way of responding to changes in its internal state.

Learn how to use strict mode in JavaScript. Strict mode is enabled by placing “use strict” at the top of your script. Frontend Developer Interview Questions

The string data type is a primitive data type that is used to represent text. In JavaScript, is there a data type for a single character? Interview Answers

String Evaluation in JavaScript works in a similar way to how it works in Python. You should never use eval in your applications.

Modifying styles and classes in JavaScript is easy. - JavaScript Interview Questions & Answers

The symbol type in JavaScript is a primitive type that is used to create unique identifiers for objects.

A built-in template element serves as a storage for HTML markup templates. It is used to create custom elements. JavaScript Frontend Phone Interview Questions

The Template Method pattern recommends breaking down an algorithm into a series of steps and then turning these steps into methods.

TextDecoder / TextEncoder is a built-in object that allows you to convert between UTF-8 and UTF-16. It is used in the browser to convert the text.

The "new" Function Syntax is a very common interview question.

The "new" operator is used to create a new object instance. What is the difference between a regular function and a constructor function? Interview Question

What are the advantages of using a Switch statement? A switch statement can replace multiple if checks, it is more descriptive, and easier to read.

The global object is the root of the JavaScript object hierarchy.

The Var Declaration is a very common interview question.

Learn how to convert data types in JavaScript. There are two types of type conversion - implicit and explicit. Frontend Developer Interview Questions

An anti-pattern is an imperfect solution to a particular problem that results in an unintended result. An anti-pattern is a lousy design worthy of documenting.

Unicode Regex is used to match text against regular expressions. It is used to match text against regular expressions. Regular Expressions Interview Questions

URL Objects are used to parse and create URLs in JavaScript. Proper implementation of URL Objects is important for security and performance reasons.

Variable Scope / Closures is a very common interview question. A closure is a function that remembers its outer variables and can access them.

JavaScript variables are used to store data. A variable is named storage for data in JavaScript. They include let, const, and var variables. Interview Questions

A visitor pattern is a behavioral pattern that enables you to decouple algorithms from the objects on which they operate.

Walking the DOM is a process of traversing the DOM tree. What does it mean in JavaScript to walk the DOM? - JavaScript interview questions and answers.

WeakMap and WeakSet are a data structure that are used to store key-value pairs. What are some use cases in applications for a WeakMap? Interview Questions

Web Components in JavaScript is used to create reusable components. Their function is encapsulated away from the rest of your code and used in your web apps.

WebSockets are used to connect to a server and exchange data. It is a standard protocol for real-time communication. JavaScript Interview Questions and Answers

A design pattern is reusable code that acts as a solution to recurring problems in JavaScript. A design pattern can be a template for solving a problem.

Learn how to use while loops and for loops in JavaScript. Loops are a way to repeat the same code multiple times in a iteration. Frontend Interview Questions.

Window Coordinates are the coordinates of the browser window. They are relative to the top left corner of the browser window. - JavaScript Interview Questions & Answers

Window Sizes / Scrolling / Resizing - Browsers also support properties like window.innerWidth/innerHeight. - JavaScript Interview Questions & Answers

A word boundary \b is a test, just like ^ and $. When the regexp engine comes across \b, it checks that the position in the string is a word boundary.

XMLHttpRequest is an older API that allows us to send and receive data from a server. XMLHttpRequest is a object that allows JavaScript to make HTTP requests.