# greatfrontend/top-javascript-interview-questions

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8,743 stars · 462 forks · MDX

## Links

- GitHub: https://github.com/greatfrontend/top-javascript-interview-questions
- Homepage: https://www.greatfrontend.com/questions/javascript-interview-questions/quiz?gnrs=github
- awesome-repositories: https://awesome-repositories.com/repository/greatfrontend-top-javascript-interview-questions.md

## Topics

`front-end-development` `interviews` `javascript` `javascript-interview-questions` `react` `reactjs` `web-development`

## Description

This project is a technical interview preparation resource focused on JavaScript. It provides a collection of common technical questions, detailed answers, and conceptual quizzes designed to help users master core language fundamentals and browser APIs.

The resource utilizes an interactive infrastructure that includes a coding workspace with in-browser runtime execution and an automated test suite to validate code correctness. It organizes content through curated learning paths and modular concept mapping to decompose complex language fundamentals into searchable study modules.

The curriculum covers extensive technical domains, including language fundamentals like prototypal inheritance and execution context, asynchronous programming and event loop management, and DOM event handling. It also includes materials on web performance optimization, data manipulation utilities, network integration, and client-side storage strategies.

## Tags

### Education & Learning Resources

- [Technical Interview Preparation](https://awesome-repositories.com/f/education-learning-resources/professional-development-career/career-development/career-advancement-resources/technical-interview-preparation.md) — Provides curated technical questions and detailed answers specifically designed for JavaScript interview preparation.
- [Curated Learning Paths](https://awesome-repositories.com/f/education-learning-resources/educational-resources/courses-training-certifications/technical-learning-roadmaps/curated-learning-paths.md) — Organizes technical JavaScript topics into sequential, curated learning paths for structured interview preparation.
- [Object Oriented Patterns](https://awesome-repositories.com/f/education-learning-resources/educational-resources/languages-and-programming-concepts/software-engineering-languages/language-fundamentals/object-oriented-patterns.md) — Provides in-depth lessons on prototypal inheritance, classes, and object-oriented patterns in JavaScript. ([source](https://cdn.jsdelivr.net/gh/greatfrontend/top-javascript-interview-questions@main/README.md))
- [Frontend Engineering Studies](https://awesome-repositories.com/f/education-learning-resources/frontend-engineering-studies.md) — Provides structured study plans and quizzes for mastering advanced JavaScript patterns and DOM manipulation.
- [Interview Preparation Guides](https://awesome-repositories.com/f/education-learning-resources/interview-preparation-guides.md) — Provides a comprehensive collection of common technical interview questions and detailed answers for JavaScript.
- [JavaScript Coding Exercises](https://awesome-repositories.com/f/education-learning-resources/javascript-coding-exercises.md) — Features an interactive environment for solving JavaScript data structure and algorithm challenges with automated tests.
- [Technical Case Studies](https://awesome-repositories.com/f/education-learning-resources/technical-case-studies.md) — Offers a knowledge base of technical interview questions and case studies based on company-specific surveys.
- [Web API Implementation Patterns](https://awesome-repositories.com/f/education-learning-resources/web-api-implementation-patterns.md) — Offers practical patterns for implementing network requests, client-side storage, and complex DOM event propagation.
- [Interactive Coding Environments](https://awesome-repositories.com/f/education-learning-resources/interactive-coding-environments.md) — Provides an interactive web-based coding workspace with syntax highlighting and real-time execution previews.
- [Technical Quiz Databases](https://awesome-repositories.com/f/education-learning-resources/technical-quiz-databases.md) — Includes a series of conceptual quizzes designed to test knowledge of the JavaScript runtime and engine.

### Part of an Awesome List

- [Coding Challenges](https://awesome-repositories.com/f/awesome-lists/learning/coding-challenges.md) — Ships an interactive coding workspace with a set of challenges and automated test validation.

### Data & Databases

- [Array Manipulation Utilities](https://awesome-repositories.com/f/data-databases/array-manipulation-utilities.md) — Teaches array and object manipulation using modern JavaScript features like spread and rest syntax. ([source](https://cdn.jsdelivr.net/gh/greatfrontend/top-javascript-interview-questions@main/README.md))
- [Object Property Accessors](https://awesome-repositories.com/f/data-databases/object-property-accessors.md) — Teaches safe property retrieval from deep object paths using optional chaining and other accessors. ([source](https://www.greatfrontend.com/blog/50-must-know-javascript-interview-questions-by-ex-interviewers))
- [Computational Result Caching](https://awesome-repositories.com/f/data-databases/key-value-stores/response-caching/computational-result-caching.md) — Teaches strategies for caching expensive function outputs to avoid redundant computations. ([source](https://www.greatfrontend.com/blog/50-must-know-javascript-interview-questions-by-ex-interviewers))
- [Deep Object Manipulations](https://awesome-repositories.com/f/data-databases/object-property-accessors/deep-object-manipulations.md) — Provides implementations for recursively merging nested objects to combine data without overwriting structures. ([source](https://www.greatfrontend.com/blog/50-must-know-javascript-interview-questions-by-ex-interviewers))

### Programming Languages & Runtimes

- [Advanced Logic Implementation](https://awesome-repositories.com/f/programming-languages-runtimes/advanced-logic-implementation.md) — Covers core language fundamentals like closures, higher-order functions, and generators. ([source](https://cdn.jsdelivr.net/gh/greatfrontend/top-javascript-interview-questions@main/README.md))
- [Asynchronous Flow Control](https://awesome-repositories.com/f/programming-languages-runtimes/asynchronous-flow-control.md) — Teaches asynchronous flow control in JavaScript using promises and async/await syntax. ([source](https://www.greatfrontend.com/blog/50-must-know-javascript-interview-questions-by-ex-interviewers))
- [Class Instantiation](https://awesome-repositories.com/f/programming-languages-runtimes/class-instantiation.md) — Provides guidance on instantiating objects from classes to define shared behaviors. ([source](https://www.greatfrontend.com/blog/50-must-know-javascript-interview-questions-by-ex-interviewers))
- [Class State Encapsulation](https://awesome-repositories.com/f/programming-languages-runtimes/class-state-encapsulation.md) — Explains the use of private fields to prevent external modification of class state. ([source](https://www.greatfrontend.com/blog/50-must-know-javascript-interview-questions-by-ex-interviewers))
- [Function Context Binding](https://awesome-repositories.com/f/programming-languages-runtimes/function-context-binding.md) — Explains how to preserve the correct object context during function execution using binding. ([source](https://www.greatfrontend.com/questions/quiz/explain-function-prototype-bind))
- [Function Context Management](https://awesome-repositories.com/f/programming-languages-runtimes/function-context-management.md) — Covers the use of call, apply, and bind for explicit this value management. ([source](https://www.greatfrontend.com/questions/quiz/explain-how-this-works-in-javascript))
- [Module Systems](https://awesome-repositories.com/f/programming-languages-runtimes/language-ecosystems-tooling/module-management/module-systems.md) — Provides instruction on JavaScript module systems and the encapsulation of reusable code. ([source](https://cdn.jsdelivr.net/gh/greatfrontend/top-javascript-interview-questions@main/README.md))
- [Execution Contexts](https://awesome-repositories.com/f/programming-languages-runtimes/language-features-paradigms/language-features/function-invocation-mechanics/execution-contexts.md) — Analyzes how execution contexts determine the behavior of the this keyword across different scopes. ([source](https://www.greatfrontend.com/questions/quiz/explain-how-this-works-in-javascript))
- [Object Creation Strategies](https://awesome-repositories.com/f/programming-languages-runtimes/object-creation-strategies.md) — Teaches different methods for object instantiation, from literals to prototype-based constructors. ([source](https://www.greatfrontend.com/questions/quiz/what-are-the-various-ways-to-create-objects-in-javascript))
- [Prototype-Based Inheritance](https://awesome-repositories.com/f/programming-languages-runtimes/programming-language-varieties/programming-languages/language-specific-resources/web-and-scripting-environments/prototype-based-inheritance.md) — Explains the implementation of property inheritance via the JavaScript prototype chain. ([source](https://www.greatfrontend.com/questions/quiz/explain-how-prototypal-inheritance-works))
- [Custom Context Invocation](https://awesome-repositories.com/f/programming-languages-runtimes/runtime-execution-environments/runtime-environments/language-runtimes/function-invocation-mechanisms/custom-context-invocation.md) — Teaches how to execute functions with explicitly defined this contexts and arguments. ([source](https://www.greatfrontend.com/questions/quiz/whats-the-difference-between-call-and-apply))
- [Timer Schedulers](https://awesome-repositories.com/f/programming-languages-runtimes/runtime-execution-environments/timer-schedulers.md) — Teaches the fundamentals of the JavaScript event loop and the scheduling of macrotasks via timers. ([source](https://www.greatfrontend.com/questions/quiz/what-is-event-loop-what-is-the-difference-between-call-stack-and-task-queue))
- [Array Flattening Utilities](https://awesome-repositories.com/f/programming-languages-runtimes/array-flattening-utilities.md) — Implements and explains utilities for flattening multi-dimensional arrays into single-level structures. ([source](https://www.greatfrontend.com/blog/50-must-know-javascript-interview-questions-by-ex-interviewers))
- [Function Argument Pre-setting](https://awesome-repositories.com/f/programming-languages-runtimes/function-argument-passing/function-argument-pre-setting.md) — Provides utilities for generating functions with pre-defined arguments via partial application. ([source](https://www.greatfrontend.com/questions/quiz/explain-function-prototype-bind))
- [Partial Application](https://awesome-repositories.com/f/programming-languages-runtimes/function-argument-passing/partial-application.md) — Implements techniques for creating continuation functions by pre-filling subset arguments. ([source](https://www.greatfrontend.com/questions/quiz/what-is-a-closure-and-how-why-would-you-use-one))
- [Object Property Descriptors](https://awesome-repositories.com/f/programming-languages-runtimes/language-features-paradigms/language-features/object-property-descriptors.md) — Demonstrates the use of property descriptors and proxies to intercept object operations. ([source](https://cdn.jsdelivr.net/gh/greatfrontend/top-javascript-interview-questions@main/README.md))
- [Object Method Borrowing](https://awesome-repositories.com/f/programming-languages-runtimes/object-method-borrowing.md) — Explains how to apply a method from one object to another using context binding. ([source](https://www.greatfrontend.com/questions/quiz/explain-function-prototype-bind))
- [Deep Equality Checking](https://awesome-repositories.com/f/programming-languages-runtimes/programming-utilities/data-structure-type-helpers/data-structure-utilities/deep-equality-checking.md) — Implements structural data comparison to determine if two nested objects or arrays are identical. ([source](https://www.greatfrontend.com/blog/50-must-know-javascript-interview-questions-by-ex-interviewers))
- [Browser-Based Runtimes](https://awesome-repositories.com/f/programming-languages-runtimes/runtime-execution-environments/runtime-environments/runtimes/javascript-and-web-standard/browser-based-runtimes.md) — Implements a browser-based runtime environment to execute JavaScript code and preview results in real time.
- [Runtime Resource Optimizations](https://awesome-repositories.com/f/programming-languages-runtimes/runtime-resource-optimizations.md) — Provides guidance on optimizing memory usage and offloading CPU-intensive tasks to background workers. ([source](https://cdn.jsdelivr.net/gh/greatfrontend/top-javascript-interview-questions@main/README.md))
- [Strict Mode Enforcement](https://awesome-repositories.com/f/programming-languages-runtimes/strict-mode-enforcement.md) — Covers the use of strict mode to prevent accidental global variables and improve error handling. ([source](https://www.greatfrontend.com/questions/quiz/what-is-use-strict-what-are-the-advantages-and-disadvantages-to-using-it))
- [Value Identity Determination](https://awesome-repositories.com/f/programming-languages-runtimes/value-identity-determination.md) — Provides methods to check if two values are the same, specifically handling NaN identity. ([source](https://www.greatfrontend.com/questions/quiz/what-is-the-difference-between-double-equal-and-triple-equal))
- [Web Worker Parallelism](https://awesome-repositories.com/f/programming-languages-runtimes/web-worker-parallelism.md) — Teaches how to use Web Workers to perform heavy computations in parallel without blocking the UI. ([source](https://www.greatfrontend.com/questions/quiz/explain-the-difference-between-synchronous-and-asynchronous-functions))

### Software Engineering & Architecture

- [Asynchronous Task Queueing](https://awesome-repositories.com/f/software-engineering-architecture/execution-control/asynchronous-task-queueing.md) — Explains the runtime management of asynchronous tasks, including timers and priority queues. ([source](https://www.greatfrontend.com/questions/quiz/what-is-event-loop-what-is-the-difference-between-call-stack-and-task-queue))
- [Microtask Queues](https://awesome-repositories.com/f/software-engineering-architecture/execution-control/concurrency-controlled-schedulers/execution-schedulers/microtask-queues.md) — Explains the microtask queue and its role in high-priority asynchronous execution within the event loop. ([source](https://www.greatfrontend.com/questions/quiz/what-is-event-loop-what-is-the-difference-between-call-stack-and-task-queue))
- [Equality Operators](https://awesome-repositories.com/f/software-engineering-architecture/execution-control/equality-validators/equality-operators.md) — Explains the difference between abstract and strict equality operators to avoid type coercion bugs. ([source](https://cdn.jsdelivr.net/gh/greatfrontend/top-javascript-interview-questions@main/README.md))
- [Performance Study Guides](https://awesome-repositories.com/f/software-engineering-architecture/performance-reliability/performance-optimization/application-performance-tuning/javascript-optimization/performance-study-guides.md) — Provides detailed guides on optimizing execution through event loop and memory management analysis.
- [Asynchronous Task Managers](https://awesome-repositories.com/f/software-engineering-architecture/asynchronous-task-managers.md) — Provides utilities for coordinating concurrent asynchronous operations and managing their resolution. ([source](https://www.greatfrontend.com/blog/50-must-know-javascript-interview-questions-by-ex-interviewers))
- [DOM Event Propagation Control](https://awesome-repositories.com/f/software-engineering-architecture/event-flow-control/dom-event-propagation-control.md) — Covers the use of bubbling and capturing to manage DOM event listeners efficiently. ([source](https://cdn.jsdelivr.net/gh/greatfrontend/top-javascript-interview-questions@main/README.md))
- [Educational Concept Mapping](https://awesome-repositories.com/f/software-engineering-architecture/hierarchical-data-structures/concept-mapping-tools/educational-concept-mapping.md) — Decomposes complex language fundamentals into modular, searchable units consisting of quizzes and detailed explanations.
- [Caching and Memoization](https://awesome-repositories.com/f/software-engineering-architecture/performance-reliability/performance-optimization/caching-memoization.md) — Provides comprehensive guides on implementing memoization to optimize repetitive complex calculations. ([source](https://www.greatfrontend.com/questions/quiz/what-is-a-closure-and-how-why-would-you-use-one))
- [Deep Copy Utilities](https://awesome-repositories.com/f/software-engineering-architecture/performance-reliability/performance-optimization/data-handling-throughput/zero-copy-mechanisms/deep-copy-utilities.md) — Provides utilities and explanations for creating deep, independent copies of complex JavaScript objects. ([source](https://www.greatfrontend.com/blog/50-must-know-javascript-interview-questions-by-ex-interviewers))
- [Closure-Based State Encapsulations](https://awesome-repositories.com/f/software-engineering-architecture/software-architecture/architectural-patterns/layering-presentation/application-layer-architectures/state-management-architectures/scope-and-hierarchy-management/closure-based-state-encapsulations.md) — Explains how to protect internal implementation details using closure-based state encapsulation. ([source](https://www.greatfrontend.com/questions/quiz/what-is-a-closure-and-how-why-would-you-use-one))
- [Value-Based Equality Checking](https://awesome-repositories.com/f/software-engineering-architecture/value-based-equality-checking.md) — Evaluates equality between values using structural and abstract comparison strategies. ([source](https://www.greatfrontend.com/questions/quiz/what-is-the-difference-between-double-equal-and-triple-equal))

### Web Development

- [Event Capturing](https://awesome-repositories.com/f/web-development/event-capturing.md) — Teaches the DOM event capturing phase to intercept events on ancestor elements before they reach the target. ([source](https://www.greatfrontend.com/questions/quiz/describe-event-capturing))
- [Event Loop Managers](https://awesome-repositories.com/f/web-development/event-loop-managers.md) — Explains the JavaScript event loop and how it coordinates synchronous and asynchronous task execution. ([source](https://cdn.jsdelivr.net/gh/greatfrontend/top-javascript-interview-questions@main/README.md))
- [Web Performance Optimizations](https://awesome-repositories.com/f/web-development/web-performance-optimizations.md) — Teaches techniques for memory management, event loop coordination, and execution scheduling to prevent UI freezing.
- [Asynchronous Content Updates](https://awesome-repositories.com/f/web-development/asynchronous-content-updates.md) — Teaches how to fetch server data in the background to refresh page content dynamically. ([source](https://www.greatfrontend.com/questions/quiz/explain-ajax-in-as-much-detail-as-possible))
- [Dynamic Element Event Handling](https://awesome-repositories.com/f/web-development/browser-integration-utilities/dom-event-handling/dynamic-element-event-handling.md) — Provides educational content on managing event listeners for elements dynamically added to the DOM. ([source](https://www.greatfrontend.com/questions/quiz/explain-event-delegation))
- [Event Context Resolution](https://awesome-repositories.com/f/web-development/browser-integration-utilities/dom-event-handling/event-context-resolution.md) — Explains how to resolve the this reference to the triggering DOM element based on function type. ([source](https://www.greatfrontend.com/questions/quiz/explain-how-this-works-in-javascript))
- [Event-Driven Observers](https://awesome-repositories.com/f/web-development/browser-integration-utilities/dom-event-handling/event-driven-observers.md) — Demonstrates the implementation of the observer pattern for decoupled communication between components. ([source](https://www.greatfrontend.com/blog/50-must-know-javascript-interview-questions-by-ex-interviewers))
- [Event Delegation](https://awesome-repositories.com/f/web-development/event-delegation.md) — Provides detailed explanations and practice for implementing event delegation to optimize memory usage. ([source](https://www.greatfrontend.com/blog/50-must-know-javascript-interview-questions-by-ex-interviewers))
- [Non-Bubbling Event Capture](https://awesome-repositories.com/f/web-development/event-delegation-systems/non-bubbling-event-capture.md) — Explains how to use the capture phase to delegate actions for events that do not naturally bubble. ([source](https://www.greatfrontend.com/questions/quiz/explain-event-delegation))
- [Main Thread Offloading](https://awesome-repositories.com/f/web-development/main-thread-offloading.md) — Covers patterns for breaking up long-running synchronous tasks to prevent main thread blocking and UI freezing. ([source](https://www.greatfrontend.com/questions/quiz/what-is-event-loop-what-is-the-difference-between-call-stack-and-task-queue))
- [Function Execution Throttling](https://awesome-repositories.com/f/web-development/rate-limiting/function-execution-throttling.md) — Includes detailed lessons on implementing debouncing and throttling to optimize high-frequency event handling. ([source](https://www.greatfrontend.com/blog/50-must-know-javascript-interview-questions-by-ex-interviewers))
- [Visual Update Coordination](https://awesome-repositories.com/f/web-development/visual-update-coordination.md) — Explains how to schedule callbacks before the browser paint step to synchronize animations with the display. ([source](https://www.greatfrontend.com/questions/quiz/what-is-event-loop-what-is-the-difference-between-call-stack-and-task-queue))

### Testing & Quality Assurance

- [Automated Test Suites](https://awesome-repositories.com/f/testing-quality-assurance/automated-test-suites.md) — Provides an automated test suite to validate the correctness of user-submitted JavaScript code snippets.
- [Precise Element Entry Detection](https://awesome-repositories.com/f/testing-quality-assurance/automation-interaction-tools/ui-automation/hybrid-element-detection/precise-element-entry-detection.md) — Teaches how to trigger callbacks specifically when a pointer enters an element, ignoring internal child movement. ([source](https://www.greatfrontend.com/questions/quiz/what-is-the-difference-between-mouseenter-and-mouseover-event))

### User Interface & Experience

- [Event Propagation Halting](https://awesome-repositories.com/f/user-interface-experience/event-propagation-systems/event-propagation-halting.md) — Teaches how to stop event movement through the DOM tree to prevent unwanted handler execution. ([source](https://www.greatfrontend.com/questions/quiz/describe-event-capturing))
- [Pointer Entry Detection](https://awesome-repositories.com/f/user-interface-experience/pointer-event-handlers/pointer-entry-detection.md) — Provides guidance on triggering callbacks when a pointer enters an element via bubbling. ([source](https://www.greatfrontend.com/questions/quiz/what-is-the-difference-between-mouseenter-and-mouseover-event))
- [Tagged Template Literals](https://awesome-repositories.com/f/user-interface-experience/tagged-template-literals.md) — Provides examples of using tagged template literals to transform strings for escaping or styling. ([source](https://www.greatfrontend.com/blog/50-must-know-javascript-interview-questions-by-ex-interviewers))