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Angular Accordion / FAQ Component

By FrontendAtlas Team · Updated Jan 30, 2026

Build a simple FAQ (accordion) component in Angular using inputs/outputs. Clicking a question should toggle its answer. By default, only one item can be open at a time, but the user can enable a mode where multiple items can stay open. Concepts: components, inputs, outputs.…

Use a standalone root component and at least one child component for…
Render a list of 3–4 FAQ items (question + answer) from an…

What you’ll build / What this tests

This premium angular coding focuses on Angular Accordion / FAQ Component. You’ll apply components and inputs thinking with intermediate level constraints. The prompt emphasizes Build a simple FAQ (accordion) component in Angular using inputs/outputs. Clicking a question should toggle its….

Learning goals

Translate the prompt into a clear angular API signature and return shape.
Apply components, inputs, outputs techniques to implement angular accordion / faq component.
Handle intermediate edge cases without sacrificing readability.
Reason about time/space complexity and trade-offs in angular.

Key decisions to discuss

Define the exact input/output contract before coding.
Prioritize predictable edge-case handling over micro-optimizations.

Evaluation rubric

Correctness: covers required behaviors and edge cases.
Clarity: readable structure and predictable control flow.
Complexity: avoids unnecessary work for large inputs.
API discipline: no mutation of inputs; returns expected shape.
Testability: solution is easy to unit test.

Constraints / Requirements

Use a standalone root component and at least one child component for a single FAQ item.
Render a list of 3–4 FAQ items (question + answer) from an in-memory array.
Clicking on a question toggles its answer open/closed.
In the default mode, only one FAQ item can be open at a time.
Add a simple control (e.g. a toggle or checkbox) to switch to 'allow multiple open' mode.
In 'allow multiple open' mode, the user should be able to open more than one FAQ item at…
Initially all FAQ items are closed.
Clicking a closed question opens its answer.
In single-open mode: opening one item automatically closes any other open item.
Switching to multi-open mode keeps already open items and allows opening others.

Mini snippet (usage only)

// Example usage
const input = /* angular accordion / faq component input */;
const result = solve(input);
console.log(result);

// Edge case check
const empty = input ?? null;
const fallback = solve(input);
console.log(fallback);

// Expected: describe output shape, not the implementation
// (no solution code in preview)

Common pitfalls

Mutating inputs instead of returning a new value.
Skipping edge cases like empty input, duplicates, or nulls.
Overlooking time complexity for large inputs.