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React Dynamic Counter Buttons (Grow-on-Click)

By FrontendAtlas Team · Updated Jan 30, 2026

In React, let users add or remove step buttons dynamically, and have each button update the counter by its own step value. Use state arrays and event handlers to keep the UI in sync. Concepts: react, state, arrays, event handlers, dynamic ui. React focus: store…

Render the dynamic counter buttons UI as the main screen.
Initially render exactly 1 counter button with value 0.

What you’ll build / What this tests

This premium react coding focuses on React Dynamic Counter Buttons (Grow-on-Click). You’ll apply react and state thinking with medium level constraints. The prompt emphasizes In React, let users add or remove step buttons dynamically, and have each button update the….

Learning goals

Translate the prompt into a clear react API signature and return shape.
Apply react, state, arrays techniques to implement react dynamic counter buttons (grow-on-click).
Handle medium edge cases without sacrificing readability.
Reason about time/space complexity and trade-offs in react.

Key decisions to discuss

Define the exact input/output contract before coding.
Choose iteration vs higher-order methods for readability.
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 the dynamic counter buttons UI as the main screen.
Initially render exactly 1 counter button with value 0.
Clicking any button increments ONLY that button’s value by 1.
After each click, append a NEW button at the bottom with value 0.
All buttons keep their own values independently.
Initial UI: one button showing 0.
Click first button once → first becomes 1, and a second button (0) appears below.
Click second button twice → second becomes 2, and two more new buttons (0, 0) are appended over…
Existing button values never reset when new buttons appear.
Use React state with an array like counts: number[].

Mini snippet (usage only)

// Example usage
const input = /* react dynamic counter buttons (grow-on-click) 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.