Vue, Angular &amp; Svelte

Explain two-way data binding and provide input binding syntax

Tests whether you see two-way binding as sugar for value binding plus an input event. Strong answer: show one syntax, then explain the prop-out, event-in pattern. Red flag: syntax only with no mention of change detection or unidirectional flow.

How do you conditionally render Login/Logout with isLoggedIn in Vue or Angular?

This tests DOM lifecycle awareness versus CSS toggling. A strong answer uses v-if/*ngIf for infrequent changes that need cleanup, and v-show/[hidden] for frequent toggles that should stay mounted. A red flag is treating them as interchangeable.

How do Vue and Angular detect nested object mutations?

Tests deep reactivity vs reference-based detection. Vue 3 Proxies catch nested mutations; Angular Default checks on zone ticks and OnPush misses same-reference changes. Fix via immutability, deep watchers, or ngDoCheck.

Architect a headless Toggle with scoped slots

This tests decoupling logic from markup via scoped slots. A strong answer exposes on and toggle through a single default scoped slot, renders no DOM, and cites UI flexibility. A red flag is using config props or CSS classes to control layout.

Implement a scoped slot pattern in a reusable DataList

It tests delegating rendering while keeping data ownership in the child. A strong answer covers a DataList that fetches internally and exposes rows via slot props, plus Angular TemplateRef via let-item. Red flag: parent loops or slots inheriting child scope.

Compare multiple boolean props versus a single status string prop

Booleans let callers pass conflicting flags like isLoading plus isError, leaking implementation priority; a single status enum makes invalid states unrepresentable.

What bindings do v-model and ngModel sugar, and why?

V-model sugars value and input; ngModel sugars [value] and (ngModelChange). This enforces one-way data flow for predictable state.

How do you emit events from a child to parent component?

This probes unidirectional data flow and child-to-parent event emission. In Vue, call $emit with a named event and payload; in Angular, use @Output with EventEmitter and emit the query. A red flag is suggesting two-way binding or direct parent mutation.

Primary mechanism for passing data from parent to child component

Tests unidirectional parent-to-child data flow and explicit component contracts. A strong answer names props or inputs, explains one-way binding, and warns against direct child mutation. Red flag: confusing props with global state or events.

Design the public API for a reusable Button component

Variant, size, disabled, type props; forward click; slots for content/icons; no router/form coupling.

How do you configure Vite Library Mode for ESM and UMD outputs?

Tests Vite Library Mode multi-format packaging. Strong answer: build.lib entry, formats es and umd, fileName function, and rollupOptions.output.globals for Vue. Red flag: multiple configs or omitting UMD global name.

How would you implement lazy loading for an Angular feature module?

This tests route-level code splitting and CLI workflows. A great answer hits: ng generate module, loadChildren in the route config, and excluding the feature from AppModule. A red flag is suggesting manual chunking instead of router-driven lazy loading.

What is a SvelteKit adapter and how do adapter-static and adapter-node differ?

Tests your grasp of SvelteKit's deployment abstraction. A strong answer outlines how adapters compile the app for a target platform, contrasting adapter-static's CDN-ready HTML with adapter-node's server-side request handler for Node environments.

Describe two key Angular CLI production build optimizations

Tests whether you know architect targets and concrete production optimizations. Strong answers name two of: dead code elimination and minification, hashed filenames for cache busting, or disabled source maps.

Explain Vite dependency pre-bundling, startup speed, and CommonJS handling

This tests whether you understand Vite's ESM-first dev server constraints. Pre-bundling converts CJS/UMD to ESM and collapses multi-file ESM deps into single modules to stop 600+ request waterfalls.

How do you configure Angular CLI dev server proxying?

Tests Angular CLI proxying to bypass CORS locally. Good answer: create proxy.conf.json with target and path, register it in angular.json serve options as proxyConfig, then restart ng serve.

How does src/routes determine routing in SvelteKit?

Src/routes mirrors URLs, folders become paths, [slug] creates dynamic params, and +page.svelte renders pages.

Why does create-vue ask about Pinia and Vitest during scaffolding?

Tests knowledge of Vue's lean core and modular tooling. Good answers note that create-vue conditionally installs deps, scaffolds folders like src/stores or tests/, and pre-configures Vite so you skip manual wiring.

ng serve purpose and fundamental difference from ng build

Ng serve compiles in memory and serves via a dev server with live reload, while ng build writes output to dist/.