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Angular Star Rating Widget

By FrontendAtlas Team · Updated Jan 30, 2026

Implement a reusable star-rating widget as an Angular standalone component. It should render a row of clickable stars, allow the user to select a rating, and notify the parent when the rating changes. Concepts: components, inputs-outputs, event-binding. Angular focus: use @Input/@Output for a controlled rating…

Create a standalone StarRatingComponent that renders a row of stars.
Support a configurable maximum number of stars via an @Input() (e.g. default…

What you’ll build / What this tests

This premium angular coding focuses on Angular Star Rating Widget. You’ll apply components and inputs-outputs thinking with easy level constraints. The prompt emphasizes Implement a reusable star-rating widget as an Angular standalone component. It should render a row of….

Learning goals

Translate the prompt into a clear angular API signature and return shape.
Apply components, inputs-outputs, event-binding techniques to implement angular star rating widget.
Handle easy 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.
Decide on concurrency and error propagation behavior.
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

Create a standalone StarRatingComponent that renders a row of stars.
Support a configurable maximum number of stars via an @Input() (e.g. default to 5).
Expose the current rating as an @Input() so the parent can control the value.
Emit an event when the user selects a rating so the parent can react (e.g. two-way binding).
Use the widget from a simple AppComponent and show the current rating below it.
Stars render from 1 up to the configured max (e.g. 5).
Clicking a star sets the rating to that star index (e.g. clicking the 4th star sets rating to…
All stars with index less than or equal to the rating appear visually "filled".
The parent component sees the updated rating value (e.g. via [(rating)] or an output event).
Use *ngFor in the star-rating template to loop over an array of star indices.

Mini snippet (usage only)

// Example usage
const input = /* angular star rating widget 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.