Add interactive Color Palette Generator web app

[Copilot]

Implements a single-page color palette generator with palette management and color locking capabilities.

Implementation

Core Features

• Random 5-color palette generation with hex display
• Individual color locking to preserve colors across regenerations
• Click-to-copy hex codes with fallback for non-HTTPS contexts
• LocalStorage persistence for saved palettes
• Keyboard shortcut (SPACE) for generation

Technical Details

• Self-contained HTML (no dependencies, no build)
• Proper hex color range (0x000000 to 0xFFFFFF)
• Clipboard API with execCommand fallback
• CSS Grid layout with staggered animations
• Fixed saved palette indexing after display reversal

Files

webapp/
├── index.html    # 477 lines - complete SPA
└── README.md     # Usage documentation

Demo

Palette generation with locked color retention:

Saved palette management:

Run by opening webapp/index.html directly in browser or via local server.

Original prompt

Create a simple, interesting, fun web app

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💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.

[austenstone]

📋 Review Summary

This PR introduces a well-designed Color Palette Generator web application with strong visual appeal and good user experience. The implementation is functional and includes modern features like local storage persistence and keyboard shortcuts. However, there are several areas that need attention related to accessibility, error handling, and code maintainability.

🔍 General Feedback

• Positive Highlights: The UI design is polished with smooth animations, the fallback clipboard implementation shows good cross-browser compatibility awareness, and the locked colors feature is a nice touch.
• Key Concerns: Missing accessibility features (ARIA labels, keyboard navigation for interactive elements), potential XSS vulnerability through innerHTML usage, and missing input validation for localStorage data.
• Architectural Notes: The single-file HTML approach is acceptable for a simple demo, but consider separating concerns (CSS/JS into separate files) if this grows in complexity.

[austenstone]

🟠 High: Random color generation comment could be clearer

The comment is accurate, but adding clarity about the hex range helps maintainability.

Suggested change

	'Teal', 'Violet', 'Crimson', 'Azure', 'Jade',
	function randomColor() {
	// Generate random hex color (0x000000 to 0xFFFFFF)
	const randomInt = Math.floor(Math.random() * 0x1000000);
	return '#' + randomInt.toString(16).padStart(6, '0');
	}

[austenstone]

🟠 High: Missing ARIA labels for accessibility

Interactive elements should have proper ARIA attributes for screen reader users to understand their purpose and state.

Suggested change

	currentPalette.forEach((color, index) => {
	card.innerHTML = `
	<div class="color-preview" style="background-color: ${color.hex}">
	<button class="lock-icon ${isLocked ? 'locked' : ''}" onclick="toggleLock(${index}, event)" aria-label="${isLocked ? 'Unlock' : 'Lock'} color ${color.hex}" aria-pressed="${isLocked}">
	${isLocked ? '🔒' : '🔓'}
	</button>
	</div>
	<div class="color-info">
	<div class="color-code">${color.hex.toUpperCase()}</div>
	<div class="color-name">${color.name}</div>
	</div>
	`;

[austenstone]

🟡 Medium: Click event handler may not work correctly

The check e.target.classList.contains('lock-icon') won't work if the user clicks on the emoji inside the button. The event target would be the emoji text node, not the button.

Suggested change

	<button class="lock-icon ${isLocked ? 'locked' : ''}" onclick="toggleLock(${index}, event)">
	card.onclick = (e) => {
	if (!e.target.closest('.lock-icon')) {
	copyToClipboard(color.hex);
	}
	};

[austenstone]

🟢 Low: Consider using try-catch for JSON.parse

While unlikely, localStorage data could be corrupted. Adding error handling would make the code more robust.

Suggested change

	textArea.style.left = '-999999px';
	function savePalette() {
	let saved = [];
	try {
	saved = JSON.parse(localStorage.getItem('savedPalettes') || '[]');
	} catch (e) {
	console.error('Failed to parse saved palettes:', e);
	saved = [];
	}
	const paletteData = currentPalette.map(c => c.hex);

[austenstone]

🟡 Medium: Missing input validation for localStorage data

The code doesn't validate that the parsed localStorage data has the expected structure. Corrupted or malicious data could cause runtime errors.

Suggested change

	// Show confirmation
	function displaySavedPalettes() {
	let saved = [];
	try {
	saved = JSON.parse(localStorage.getItem('savedPalettes') || '[]');
	if (!Array.isArray(saved)) saved = [];
	} catch (e) {
	console.error('Failed to parse saved palettes:', e);
	saved = [];
	}
	const container = document.getElementById('savedPalettes');
	const list = document.getElementById('savedPalettesList');

[austenstone]

🟡 Medium: Missing validation for loaded palette data

The function doesn't validate that the palette structure is correct before using it. This could cause errors if the data is corrupted.

Suggested change

	currentPalette = palette.colors.map(hex => ({
	function loadPalette(index) {
	const saved = JSON.parse(localStorage.getItem('savedPalettes') || '[]');
	const palette = saved[index];
	if (!palette || !Array.isArray(palette.colors)) {
	console.error('Invalid palette data');
	return;
	}
	currentPalette = palette.colors.map(hex => ({
	hex: hex,
	name: randomColorName()
	}));

[austenstone]

/copilot fetch this PR and changes made in it. Create a separate PR with tests that test the functionality.

[austenstone]

✅ Task completed! Created PR #35 with comprehensive test suite (20 automated tests) for the Color Palette Generator. Tests cover color generation, locking, storage, and UI interactions. View: #35