Question 1

What is a Design System and what value does it bring to an organization?

Accepted Answer

A Design System is a coherent collection of principles, guidelines, and reusable components that enable building user interfaces consistently and efficiently across an organization.

The components of a Design System include design principles first. These are fundamental values that guide design decisions. For example, accessibility first, or clarity before aesthetics.

Second are design tokens. These are the atomic values of the system including colors, typography, spacing, shadows, and animations. They are the shared source of truth between designers and developers.

Third is the compo

Question 2

Explain the Atomic Design methodology and how it structures components in a Design System.

Accepted Answer

Atomic Design is a methodology created by Brad Frost that structures user interfaces into five distinct levels, from the smallest unit to the complete page.

The five levels of Atomic Design start with Atoms at the first level. These are the indivisible base elements of the interface. For example, a button, a label, an input, an icon, or an avatar. They cannot be broken down further without losing functionality. Each atom is styled via design tokens.

Second level is Molecules. These are groups of atoms that work together as a unit. For example, a form field combining a label, an input, an

Question 3

What are the core principles of a well-designed frontend architecture?

Accepted Answer

A well-designed frontend architecture follows several core principles that enable scalability, maintainability, and team productivity.

Separation of Concerns is fundamental. The architecture should clearly separate UI components from business logic, data fetching from rendering, and state management from presentation. This separation makes code easier to test, modify, and understand.

Modularity means organizing code into self-contained, reusable modules. Each module should have a single responsibility and expose a clear public API. Modules can be composed to build complex features withou

Question 4

How do you approach folder structure in a large frontend application?

Accepted Answer

Folder structure significantly impacts developer productivity and code discoverability. There are two main approaches, each with distinct trade-offs.

Feature-based structure groups all code related to a feature together. For a user profile feature, you would have a folder containing the components, hooks, utilities, tests, and types specific to that feature. This approach excels in large applications because developers work primarily within a single folder when building or modifying features. It also makes code deletion safer since feature boundaries are clear.

Layer-based structure grou

Question 5

What is the role of a JavaScript bundler, and why do we need one in modern frontend development?

Accepted Answer

A JavaScript bundler takes your source code, composed of many files and modules, and transforms it into one or more optimized files for the browser.

Why we need bundlers in modern development.

First, module management. Modern code is organized into modules with imports and exports. Historically, browsers did not support ES modules. Even today, loading hundreds of small files via HTTP would be inefficient. The bundler combines modules into larger files.

Second, code transformation. Modern JavaScript uses syntax like JSX, TypeScript, or the latest ES features. Older browsers do not unde

Question 6

How does Vite work, and why is it so fast in development compared to webpack?

Accepted Answer

Vite, created by Evan You, the creator of Vue.js, revolutionizes the frontend development experience through a fundamentally different approach to bundling.

The traditional webpack approach.

webpack analyzes all your code, resolves all dependencies, and creates a complete bundle before starting the development server. The larger your application grows, the slower this cold start becomes. For a large application, this can take several seconds or even minutes.

The Vite approach in development.

First, no initial bundling. Vite starts the server immediately without bundling the applica

Question 7

Au-delà des Core Web Vitals, quelles métriques de performance surveillez-vous et comment les mesurez-vous en production ?

Accepted Answer

Les Core Web Vitals, LCP, FID remplacé par INP, et CLS, sont essentiels mais ne racontent pas toute l''histoire. Un monitoring de performance complet inclut des métriques supplémentaires.

**Métriques de chargement :**

**TTFB, Time To First Byte.** Le temps entre la requête et le premier octet de la réponse. Il mesure la latence réseau et la performance du serveur. Un bon TTFB est inférieur à huit cents millisecondes.

**FCP, First Contentful Paint.** Le moment où le premier contenu, texte ou image, apparaît. Un bon FCP est inférieur à une virgule huit secondes.

**TTI, Time To Intera

Question 8

Comment fonctionne la gestion de la mémoire en JavaScript et quelles sont les causes courantes de fuites de mémoire dans les applications frontend ?

Accepted Answer

JavaScript utilise un garbage collector automatique pour gérer la mémoire. Comprendre son fonctionnement aide à éviter les fuites de mémoire qui dégradent progressivement les performances.

**Comment fonctionne le Garbage Collector :**

**L''algorithme Mark and Sweep.** Le GC identifie les objets atteignables à partir des racines, qui sont les variables globales et la stack d''exécution. Tout objet qui ne peut pas être atteint depuis une racine est considéré comme garbage et sa mémoire est libérée.

**Les générations.** Les moteurs modernes utilisent un GC générationnel. Les objets récen

Question 9

What are the responsibilities of a Senior Frontend Developer beyond writing code?

Accepted Answer

A Senior Frontend Developer has responsibilities that extend well beyond producing code. The role evolves toward being an impact multiplier who elevates the entire team.

Technical responsibilities expand significantly.

First, architecture decisions. The senior guides technical choices: which library to adopt, which project structure to follow, which patterns to use. These decisions impact the team long-term.

Second, code quality. The senior defines and maintains quality standards. They set up linters, tests, and best practices. They ensure code is maintainable and performant.

Third

Question 10

What are the best practices for conducting effective and constructive code reviews?

Accepted Answer

Code reviews are a pillar of code quality and knowledge sharing. Done well, they elevate the entire team. Done poorly, they become a source of friction.

Objectives of a code review.

First, ensure quality. Find bugs, performance issues, and security flaws before they reach production.

Second, maintain consistency. Ensure code follows team conventions and patterns.

Third, share knowledge. At least two people know each part of the code. Reviewers learn too.

Principles for the reviewer.

Be constructive, not destructive. Criticize the code, not the person. Instead of saying this i

Frontend Developer

Topics

Design Systems

Architecture Patterns

Build Tools & Bundlers

Performance Deep Dive

Team Leadership

Mock Interview

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