Premium

Autocomplete Search Bar (Standalone Component)

By FrontendAtlas Team · Updated Jan 30, 2026

Build an autocomplete search bar in Angular. As the user types, show a dropdown of suggestions filtered from a dataset. Add debounced searching, mouse selection, and keyboard navigation (↑/↓/Enter/Escape). Framework focus: Angular templates + standalone components, @Input/@Output, and RxJS/async pipe patterns.

Use a standalone Angular component as the root component.
Use ReactiveFormsModule and a FormControl for the input binding.

What you’ll build / What this tests

This premium angular coding focuses on Autocomplete Search Bar (Standalone Component). You’ll apply components and forms thinking with medium level constraints. The prompt emphasizes Build an autocomplete search bar in Angular. As the user types, show a dropdown of suggestions….

Learning goals

Translate the prompt into a clear angular API signature and return shape.
Apply components, forms, reactive-forms techniques to implement autocomplete search bar (standalone component).
Handle medium 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

Use a standalone Angular component as the root component.
Use ReactiveFormsModule and a FormControl for the input binding.
Show a dropdown of suggestions filtered by the current query (case-insensitive, substring match).
Debounce input changes (e.g. 250–400ms) before searching.
Support mouse selection (mousedown on a suggestion sets the input value and closes dropdown).
Support keyboard navigation: ArrowDown/ArrowUp moves active option, Enter selects, Escape closes.
Close the dropdown when clicking outside the component.
Basic accessibility: use role="combobox", role="listbox", role="option", plus aria-expanded and aria-activedescendant.
Typing updates suggestions after the debounce delay.
If query is empty/whitespace, dropdown is closed and no suggestions are shown.

Mini snippet (usage only)

// Example usage
const input = /* autocomplete search bar (standalone 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.