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Nested Checkbox Tree (Standalone Component)

By FrontendAtlas Team · Updated Jan 30, 2026

Build a standalone Angular component that renders a parent checkbox with multiple child checkboxes. Toggling the parent should check/uncheck all children. Toggling children should update the parent to checked, unchecked, or indeterminate depending on the child states. Concepts: components, dom, forms. Framework focus: Angular templates…

Render one parent checkbox and several child checkboxes.
Checking the parent selects all children.

What you’ll build / What this tests

This premium angular coding focuses on Nested Checkbox Tree (Standalone Component). You’ll apply components and dom thinking with intermediate level constraints. The prompt emphasizes Build a standalone Angular component that renders a parent checkbox with multiple child checkboxes. Toggling the….

Learning goals

Translate the prompt into a clear angular API signature and return shape.
Apply components, dom, forms techniques to implement nested checkbox tree (standalone 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.
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

Render one parent checkbox and several child checkboxes.
Checking the parent selects all children.
Unchecking the parent clears all children.
When children are toggled manually:
- If all are checked → parent becomes checked.
- If none are checked → parent becomes unchecked.
- If some are checked → parent becomes indeterminate.
Use a standalone Angular component.
Use simple arrays or booleans for state (no signals needed).
Parent reflects the state of the children.

Mini snippet (usage only)

// Example usage
const input = /* nested checkbox tree (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.