Why would you choose Vue.js over React or Angular for a medium-sized project?

Vue offers a balance between React's flexibility and Angular's structure with a more accessible learning curve. It is ideal when the team is small or medium, productivity from day one is needed, and Angular's architectural rigidity is not required.

What is the difference between the Options API and the Composition API in Vue 3?

The Options API organizes code by option type like data, methods, and computed, being more intuitive for beginners. The Composition API organizes code by related logic with setup(), facilitating reuse through composables and being more suitable for complex components and TypeScript.

When would you use Vue with Nuxt.js instead of pure Vue as a SPA?

When the project requires SEO, good initial load performance, static page generation, or a more opinionated project structure. Pure Vue as a SPA is suitable for internal applications or dashboards where SEO is not relevant.

What advantage does Vue's reactivity system offer compared to React?

Vue automatically tracks reactive dependencies without needing to manually declare dependency arrays like in useEffect. Computed values and watchers update automatically when their dependencies change, reducing synchronization errors.

When would you extract logic from a Vue component into a composable?

When stateful logic needs to be reused across multiple components, when a component mixes too many responsibilities, or when you want to test the logic independently from the presentation. Composables are the equivalent of React's custom hooks in Vue 3.

What is Pinia and why did it replace Vuex as the official state solution?

Pinia is the official state management library for Vue 3. It replaced Vuex due to its simpler API without mutations, native TypeScript support, integrated DevTools, and an architecture based on independent stores that scales better in large projects.

How does Vue handle communication between parent and child components?

From parent to child through props that flow in one direction. From child to parent through events emitted with emit. For communication between components not hierarchically related, Pinia is used for global state or provide/inject for dependencies in the component tree.

For what projects does Vue have a clear advantage over using vanilla JavaScript?

In applications with interfaces that change frequently in response to data, multiple views with navigation, shared state between components, or reusable UI logic. Vue's reactivity system adds special value in forms and views that reflect changing data.

How does Vue 3's reactivity system work internally?

Vue 3 uses JavaScript Proxies to intercept accesses and mutations on reactive objects created with reactive() or ref(). When a reactive property is accessed inside an effect like computed or watchEffect, Vue registers the dependency and re-executes the effect automatically when the value changes.

What is the difference between ref and reactive in Vue 3?

ref creates a reactive value of any type accessible with .value, suitable for primitives and when the complete reference needs to be reassigned. reactive creates a reactive object without needing .value, more ergonomic for objects with multiple properties but doesn't work with primitives nor allows reassignment.

What is the difference between computed and watch in Vue?

computed defines derived values that are automatically recalculated when their dependencies change and are cached until a dependency changes. watch observes changes in reactive sources to execute side effects like API calls or logging. computed is preferable when the result can be expressed as a transformation.

How would you implement authentication and route protection in Vue with Vue Router?

Using navigation guards with router.beforeEach() that check if the user is authenticated by querying a Pinia store before each navigation. If not authenticated, they redirect to login. Meta fields on routes allow marking which routes require authentication.

How would you handle data fetching in a modern Vue application?

With VueUse composables like useFetch for simple cases, or with TanStack Query for Vue which manages cache, loading and error states, revalidation, and synchronization. It avoids reinventing this logic with ref and watch manually, which generates code prone to race conditions.

When would you use provide and inject in Vue and what are their limitations?

To pass data or services to descendant components without prop drilling, especially in component libraries or when the hierarchy is deep. Their limitation is that dependencies are implicit and hard to trace, so for complex global state Pinia is preferable.

How would you optimize the performance of a long list of components in Vue?

Using the v-memo directive to memoize subtrees that rarely change, virtual scrolling with vue-virtual-scroller for lists of thousands of elements, and avoiding expensive watchers on components that are instantiated many times.

How would you structure a Pinia store for a complex domain?

Creating one store per business domain with state, getters for derived values, and actions for mutations and asynchronous operations. Stores can compose by importing each other. A single global store that mixes unrelated domains is avoided.

How would you structure a large Vue application with multiple business domains?

By organizing code by feature with each domain containing its own components, composables, Pinia stores, and tests. A service layer centralizes API communication. Barrel exports are used for clean imports and lazy loading of routes to optimize the initial bundle.

How would you design a reusable Vue component library for multiple projects?

By creating highly configurable components with well-typed props in TypeScript, using slots for maximum content flexibility, documenting with Histoire or Storybook, publishing with Vite Library Mode, and ensuring accessibility in each component from its initial design.

When would you consider migrating from pure Vue to Nuxt.js in an existing project?

When SEO becomes a priority, when initial load times affect user retention, when static content generation is needed, or when the team wants to leverage Nuxt's automatic routing and conventions to reduce configuration.

How would you implement SSR with Vue and what considerations does it have in production?

With Nuxt.js which manages client hydration and server-side rendering. The main considerations are avoiding access to browser APIs on the server, managing state between server and client without duplicating requests, and correctly configuring response caching on the server.

How would you approach testing complex composables with reactive state in Vue?

Using @vue/test-utils with mountComposable or withSetup to create a component context, Jest for assertions, and Vitest as a faster alternative integrated with Vite. Pure composables without side effects are tested directly by instantiating them in the test context.

How would you ensure architectural consistency in a large team working with Vue?

By defining documented conventions on when to use Composition API vs Options API, folder structure by feature, composable and store naming conventions, ESLint with vue/recommended and custom rules, and code reviews with an architectural checklist.

Not knowing the Composition API in Vue 3 projects

Working exclusively with Options API in Vue 3 without knowing the Composition API reflects being out of date. In interviews for mid and senior positions with Vue 3, mastery of the Composition API and its advantages for reusable logic is expected.

Confusing ref and reactive or not knowing when to use each one

Not being clear on the difference between ref and reactive or applying them without criteria reflects a superficial understanding of Vue 3's reactivity system. It is one of the most frequent technical questions in Vue 3 interviews.

Not knowing Pinia as a replacement for Vuex

Proposing Vuex for a new Vue 3 project without mentioning Pinia reflects being out of date. Pinia is the official recommended solution since Vue 3 and its lack of knowledge in current interviews is a sign of not following the ecosystem.

Not justifying Vue over React with technical criteria

Not being able to articulate the real differences between Vue and React beyond syntax reflects a lack of judgment for recommending technologies. Being able to explain when Vue adds value over React and vice versa is expected.

Overusing watchers when computed would be sufficient

Using watch to calculate derived values when computed is the right tool generates more complex and less efficient code. It is a frequent mistake among developers coming from React who don't understand the difference between both.

Not knowing Nuxt.js when the project requires SSR or SEO

Proposing pure Vue for an application with SEO requirements without evaluating Nuxt reflects a lack of ecosystem knowledge. In interviews, knowing when pure Vue is sufficient and when Nuxt adds real value is expected.

Vue.js

The progressive JavaScript framework for user interfaces

Vue.js is a progressive framework for building user interfaces that can be adopted incrementally. It combines the best of React and Angular with an accessible syntax, declarative reactivity, and a flexible component architecture. Its modern Composition API makes it competitive for projects of any scale.

JavaScriptTypeScriptComponentsComposition API

Market demand

Vue.js has high adoption in Asia, Europe, and Latin America, especially in startups and medium-sized companies. It is the preferred framework in teams that seek productivity without Angular's complexity or React's unstructured freedom.

High adoption in startups and SMEsVery popular in Asia and EuropeStrong growth with Vue 3

Technical requirements

Intermediate

Requires mastery of modern JavaScript and reactive programming concepts. Vue 3's Composition API benefits from TypeScript knowledge. Familiarity with the component lifecycle and the reactivity system is essential for real projects.

Use cases

Real Projects

Vue.js is used to develop:

Medium and high complexity SPA web applications
Dashboards and administrative interfaces
Platforms with Nuxt.js for SSR and static generation
Progressive applications integrated into existing systems

Types of Company

Vue.js is adopted by:

Tech startups with small or medium frontend teams
Product companies with JavaScript stack
Digital agencies with varied projects
Companies migrating from jQuery or legacy frameworks

Production Scenarios

Vue.js is widely used in production environments such as:

SPAs with routing and moderately complex global state
Applications with forms and dynamic validations
Interfaces with real-time data integration
Applications with SSR using Nuxt.js for SEO

Scalability

Vue.js offers multiple mechanisms to scale applications:

Lazy loading of components and routes with Vue Router
Scalable state management with Pinia
Server-side rendering with Nuxt.js
Optimization with Composition API and reactive computed properties

Advantages and Disadvantages

Advantages

Smoother learning curve than Angular with more structure than React.

Modern Composition API that facilitates logic reuse with composables.

Excellent official documentation considered a reference in the industry.

Disadvantages

Lower adoption than React in the global job market.

Smaller ecosystem compared to React.

The flexibility between Options API and Composition API can generate inconsistencies in teams without clear conventions.

Comparison

Advantages of React

Greater global job demand
Larger ecosystem
Greater adoption in American tech companies

Considerations

React has a greater market presence but Vue offers a more integrated development experience with fewer decisions about the stack. Vue is preferable when team productivity is prioritized over market demand.