React Development

Role in This Project

React is used only for interactive islands — calculator forms, dynamic UI, and anything that needs client-side state. All static content is rendered by Astro.

Component Pattern

interface TileCalculatorProps {
  baseUrl?: string;
}

export default function TileCalculator({ baseUrl = '' }: TileCalculatorProps) {
  // component logic
  return (/* JSX */);
}

Do NOT use FC type. Use regular function declarations with typed props.

Rules

• •Functional components only. No class components.
• •Export as default from calculator component files (required for Astro island imports).
• •No business logic in components. Import calculator functions from src/calculators/. Components handle state and UI only.
• •Use controlled form inputs with useState for calculator forms.

State Management

• •Local state: useState for component-scoped state (form inputs, results).
• •Cross-island state: Use Nanostores if multiple islands need shared state. Nanostores works with both Astro and React.
• •Do NOT use Zustand, Redux, or Context — Nanostores is the standard for Astro multi-framework islands.

Calculator Component Structure

import { useState } from 'react';
import { calculateTiles } from '../../calculators/tiles';
import type { TileInput, TileResult } from '../../calculators/tiles';

export default function TileCalculator() {
  const [input, setInput] = useState<TileInput>(defaultInput);
  const [result, setResult] = useState<TileResult | null>(null);

  const handleCalculate = () => {
    setResult(calculateTiles(input));
  };

  return (
    <div>
      {/* Input form */}
      {/* Calculate button */}
      {/* Results display (conditional on result !== null) */}
    </div>
  );
}

Performance

• •Use useMemo for expensive derived calculations.
• •Use useCallback only when passing callbacks to memoised children.
• •Do NOT premature-optimise — profile first.