Programming Languages & Core Development Topics
Programming languages, development fundamentals, coding concepts, and core data structures. Includes syntax, algorithms, memory management at a programming level, asynchronous patterns, and concurrency primitives. Also covers core data manipulation concepts like hashing, collections, error handling, and DOM manipulation for web development. Excludes tool-specific proficiency (see 'Tools, Frameworks & Implementation Proficiency').
Modern JavaScript/TypeScript Fundamentals
ES6+ features (arrow functions, destructuring, spread operator, async/await, promises), closures, prototypes, and this binding. TypeScript basics including interfaces, generics, and type narrowing. Understanding of functional vs object-oriented paradigms.
Browser APIs and Web Platform
Practical knowledge of core browser platform features and their performance, security, and reliability trade offs. Topics include the Document Object Model for traversal and manipulation, event handling and delegation, storage APIs such as local storage and IndexedDB, the Fetch API and XMLHttpRequest, IntersectionObserver and ResizeObserver for efficient rendering, Web Workers and service workers for background tasks, and considerations around serialization, thread boundaries, and resource limits. Candidates should also be able to measure and debug platform interactions and reason about when to use a particular web platform primitive.
Whiteboard Coding and Communication
Ability to produce clear, correct solutions in an interview setting without executing code while narrating your thought process effectively. This includes problem decomposition, selecting appropriate data structures and algorithms, writing readable pseudocode or code on a whiteboard or shared editor, explaining assumptions and trade offs, walking through example inputs and edge cases, and iterating on solutions in response to feedback. Candidates should demonstrate clarity of communication, time management, and the ability to translate a high level approach into implementable, testable steps while keeping stakeholders aligned.
Modern JavaScript Fundamentals
Focuses on modern JavaScript language features, semantics, and runtime behavior used in frontend and general JavaScript development. Topics include ES2015 and newer syntax and constructs such as arrow functions, destructuring, spread and rest operators, template literals, let and const scoping, classes, and modules. Also include asynchronous programming patterns and runtime concepts such as Promises, async and await, the event loop, callback queue and microtask queue, closure, scope and hoisting, prototypal inheritance and the this keyword, and common browser concerns such as event handling, basic DOM manipulation, and interaction with browser APIs. Interviewers assess both conceptual understanding and practical usage, including debugging and choosing idiomatic patterns.
JavaScript Fundamentals and Design Patterns
Assess deep understanding of the JavaScript language and how to architect maintainable modular code without relying solely on frameworks. Topics include closures the prototype chain this binding scoping and the event loop including microtask and macrotask behavior. Expect questions on asynchronous patterns such as callbacks promises and async await error propagation and cancellation and on DOM event delegation and manipulation. Candidates should also explain common design patterns such as Observer Module Singleton Factory and when to apply them to build testable performant vanilla JavaScript solutions.
Concurrency Bugs and Debugging Techniques
Understand common concurrency bugs: race conditions, deadlock, data corruption, and priority inversion. Discuss how to reproduce, diagnose, and fix concurrency issues. Understand challenges of debugging concurrent systems. Discuss defensive programming practices that prevent concurrency bugs.
Error Handling and Code Quality
Focuses on writing production quality code and scripts that are defensive, maintainable, and fail gracefully. Covers anticipating and handling failures such as exceptions, missing files, network errors, and process exit codes; using language specific constructs for error control for example try except blocks in Python or set minus e patterns in shell scripts; validating inputs; producing clear error messages and logs; and avoiding common pitfalls that lead to silent failures. Also includes code quality best practices such as readable naming and code structure, using standard libraries instead of reinventing functionality, writing testable code and unit tests, and designing for maintainability and observability.
Error Handling and Defensive Programming
Covers designing and implementing defensive, fault tolerant code and system behaviors to prevent and mitigate production failures. Topics include input validation and sanitization, null and missing data handling, overflow and boundary protections, exception handling and propagation patterns, clear error reporting and structured logging for observability, graceful degradation and fallback strategies, retry and backoff policies and idempotency for safe retries. Also address concurrency and synchronization concerns, resource and memory management to avoid exhaustion, security related input checks, and how to document and escalate residual risks. Candidates should discuss pragmatic trade offs between robustness and complexity, show concrete defensive checks and assertions, and describe test strategies for error paths including unit tests and integration tests and how monitoring and operational responses tie into robustness.
Core Fullstack Technologies
Brief overview of your proficiency with frontend technologies (HTML, CSS, JavaScript frameworks), backend technologies (server-side languages, APIs), and databases. Be honest about depth vs breadth at junior level.