@sc4rfurryx/proteusjs
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The Modern Web Development Framework for Accessible, Responsive, and High-Performance Applications. Intelligent container queries, fluid typography, WCAG compliance, and performance optimization.
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text/typescript
/**
* Comprehensive Accessibility Engine for ProteusJS
* WCAG compliance, screen reader support, and cognitive accessibility
*/
import { logger } from '../utils/Logger';
export interface AccessibilityConfig {
wcagLevel: 'AA' | 'AAA';
screenReader: boolean;
keyboardNavigation: boolean;
motionPreferences: boolean;
colorCompliance: boolean;
cognitiveAccessibility: boolean;
announcements: boolean;
focusManagement: boolean;
skipLinks: boolean;
landmarks: boolean;
autoLabeling: boolean;
enhanceErrorMessages: boolean;
showReadingTime: boolean;
simplifyContent: boolean;
readingLevel: 'elementary' | 'middle' | 'high' | 'college';
}
export interface AccessibilityState {
prefersReducedMotion: boolean;
prefersHighContrast: boolean;
screenReaderActive: boolean;
keyboardUser: boolean;
focusVisible: boolean;
currentFocus: Element | null;
announcements: string[];
violations: AccessibilityViolation[];
}
export interface AccessibilityViolation {
type: 'color-contrast' | 'focus-management' | 'aria-labels' | 'keyboard-navigation' | 'motion-sensitivity' | 'text-alternatives' | 'semantic-structure' | 'timing' | 'seizures';
element: Element;
description: string;
severity: 'error' | 'warning' | 'info';
wcagCriterion: string;
impact: 'minor' | 'moderate' | 'serious' | 'critical';
helpUrl?: string;
suggestions: string[];
}
export interface AccessibilityReport {
score: number; // 0-100
level: 'AA' | 'AAA';
violations: AccessibilityViolation[];
passes: number;
incomplete: number;
summary: {
total: number;
errors: number;
warnings: number;
info: number;
};
recommendations: string[];
}
export interface WCAGCriterion {
id: string;
level: 'A' | 'AA' | 'AAA';
title: string;
description: string;
techniques: string[];
}
// Enhanced Helper Classes with Full Implementation
class FocusTracker {
private focusHistory: Element[] = [];
private keyboardUser: boolean = false;
constructor(private element: Element) {
this.setupKeyboardDetection();
}
private setupKeyboardDetection(): void {
document.addEventListener('keydown', (e) => {
if (e.key === 'Tab') {
this.keyboardUser = true;
document.body.classList.add('keyboard-user');
}
});
document.addEventListener('mousedown', () => {
this.keyboardUser = false;
document.body.classList.remove('keyboard-user');
});
}
activate(): void {
this.element.addEventListener('focusin', this.handleFocusIn.bind(this) as EventListener);
this.element.addEventListener('focusout', this.handleFocusOut.bind(this) as EventListener);
}
deactivate(): void {
if (this.element && typeof this.element.removeEventListener === 'function') {
this.element.removeEventListener('focusin', this.handleFocusIn.bind(this) as EventListener);
this.element.removeEventListener('focusout', this.handleFocusOut.bind(this) as EventListener);
}
}
private handleFocusIn(event: Event): void {
const target = event.target as Element;
this.focusHistory.push(target);
// Keep only last 10 focus events
if (this.focusHistory.length > 10) {
this.focusHistory.shift();
}
}
private handleFocusOut(event: Event): void {
// Handle focus out logic
}
auditFocus(): AccessibilityViolation[] {
const violations: AccessibilityViolation[] = [];
// Check for focus traps
const focusableElements = this.element.querySelectorAll(
'a[href], button, input, select, textarea, [tabindex]:not([tabindex="-1"])'
);
focusableElements.forEach((element) => {
// Check if element has visible focus indicator
const computedStyle = window.getComputedStyle(element);
const hasOutline = computedStyle.outline !== 'none' && computedStyle.outline !== '0px';
const hasBoxShadow = computedStyle.boxShadow !== 'none';
if (!hasOutline && !hasBoxShadow) {
violations.push({
type: 'focus-management',
element,
description: 'Focusable element lacks visible focus indicator',
severity: 'error',
wcagCriterion: '2.4.7',
impact: 'serious',
suggestions: [
'Add :focus outline or box-shadow',
'Ensure focus indicator has sufficient contrast',
'Make focus indicator clearly visible'
]
});
}
});
return violations;
}
}
class ColorAnalyzer {
private contrastThresholds = {
'AA': { normal: 4.5, large: 3.0 },
'AAA': { normal: 7.0, large: 4.5 }
};
constructor(private wcagLevel: 'AA' | 'AAA') {}
activate(element: Element): void {
// Monitor for color changes
const observer = new MutationObserver((mutations) => {
mutations.forEach((mutation) => {
if (mutation.type === 'attributes' &&
(mutation.attributeName === 'style' || mutation.attributeName === 'class')) {
this.checkElementContrast(mutation.target as Element);
}
});
});
observer.observe(element, {
attributes: true,
subtree: true,
attributeFilter: ['style', 'class']
});
}
deactivate(): void {
// Cleanup observers
}
auditContrast(element: Element): AccessibilityViolation[] {
const violations: AccessibilityViolation[] = [];
const textElements = element.querySelectorAll('*');
textElements.forEach((el) => {
const hasText = el.textContent && el.textContent.trim().length > 0;
if (!hasText) return;
const contrastRatio = this.calculateContrastRatio(el);
const isLargeText = this.isLargeText(el);
const threshold = this.contrastThresholds[this.wcagLevel][isLargeText ? 'large' : 'normal'];
if (contrastRatio < threshold) {
violations.push({
type: 'color-contrast',
element: el,
description: `Insufficient color contrast: ${contrastRatio.toFixed(2)}:1 (required: ${threshold}:1)`,
severity: 'error',
wcagCriterion: this.wcagLevel === 'AAA' ? '1.4.6' : '1.4.3',
impact: 'serious',
suggestions: [
'Increase color contrast between text and background',
'Use darker text on light backgrounds',
'Use lighter text on dark backgrounds',
'Test with color contrast analyzers'
]
});
}
});
return violations;
}
private calculateContrastRatio(element: Element): number {
const computedStyle = window.getComputedStyle(element);
const textColor = this.parseColor(computedStyle.color);
const backgroundColor = this.getBackgroundColor(element);
const textLuminance = this.getLuminance(textColor);
const backgroundLuminance = this.getLuminance(backgroundColor);
const lighter = Math.max(textLuminance, backgroundLuminance);
const darker = Math.min(textLuminance, backgroundLuminance);
return (lighter + 0.05) / (darker + 0.05);
}
private parseColor(colorString: string): [number, number, number] {
// Simplified color parsing - in production, use a robust color parser
const rgb = colorString.match(/rgb\((\d+),\s*(\d+),\s*(\d+)\)/);
if (rgb && rgb[1] && rgb[2] && rgb[3]) {
return [parseInt(rgb[1]), parseInt(rgb[2]), parseInt(rgb[3])];
}
return [0, 0, 0]; // Default to black
}
private getBackgroundColor(element: Element): [number, number, number] {
let currentElement = element as HTMLElement;
while (currentElement && currentElement !== document.body) {
const computedStyle = window.getComputedStyle(currentElement);
const backgroundColor = computedStyle.backgroundColor;
if (backgroundColor && backgroundColor !== 'rgba(0, 0, 0, 0)' && backgroundColor !== 'transparent') {
return this.parseColor(backgroundColor);
}
currentElement = currentElement.parentElement as HTMLElement;
}
return [255, 255, 255]; // Default to white
}
private getLuminance([r, g, b]: [number, number, number]): number {
const [rs, gs, bs] = [r, g, b].map(c => {
c = c / 255;
return c <= 0.03928 ? c / 12.92 : Math.pow((c + 0.055) / 1.055, 2.4);
});
return 0.2126 * (rs || 0) + 0.7152 * (gs || 0) + 0.0722 * (bs || 0);
}
private isLargeText(element: Element): boolean {
const computedStyle = window.getComputedStyle(element);
const fontSize = parseFloat(computedStyle.fontSize);
const fontWeight = computedStyle.fontWeight;
// Large text is 18pt (24px) or 14pt (18.66px) bold
return fontSize >= 24 || (fontSize >= 18.66 && (fontWeight === 'bold' || parseInt(fontWeight) >= 700));
}
private checkElementContrast(element: Element): void {
const violations = this.auditContrast(element);
if (violations.length > 0) {
logger.warn('Color contrast violations detected:', violations);
}
}
fixContrast(element: Element): void {
const violations = this.auditContrast(element);
violations.forEach(violation => {
if (violation.type === 'color-contrast') {
// Apply automatic contrast fixes
const htmlElement = violation.element as HTMLElement;
// Simple fix: make text darker or lighter based on background
const backgroundColor = this.getBackgroundColor(violation.element);
const backgroundLuminance = this.getLuminance(backgroundColor);
if (backgroundLuminance > 0.5) {
// Light background - use dark text
htmlElement.style.color = '#000000';
} else {
// Dark background - use light text
htmlElement.style.color = '#ffffff';
}
logger.info('Applied contrast fix to element:', htmlElement);
}
});
}
updateContrast(highContrast: boolean): void {
if (highContrast) {
document.body.classList.add('high-contrast');
// Apply high contrast styles
const style = document.createElement('style');
style.id = 'proteus-high-contrast';
style.textContent = `
.high-contrast * {
background-color: white !important;
color: black !important;
border-color: black !important;
}
.high-contrast a {
color: blue !important;
}
.high-contrast button {
background-color: white !important;
color: black !important;
border: 2px solid black !important;
}
`;
if (!document.getElementById('proteus-high-contrast')) {
document.head.appendChild(style);
}
} else {
document.body.classList.remove('high-contrast');
const style = document.getElementById('proteus-high-contrast');
if (style) {
style.remove();
}
}
}
}
export class AccessibilityEngine {
private element: Element;
private config: Required<AccessibilityConfig>;
private state: AccessibilityState;
private liveRegion: HTMLElement | null = null;
private focusTracker: FocusTracker;
private colorAnalyzer: ColorAnalyzer;
private motionManager: MotionManager;
constructor(element: Element, config: Partial<AccessibilityConfig> = {}) {
this.element = element;
this.config = {
wcagLevel: 'AA',
screenReader: true,
keyboardNavigation: true,
motionPreferences: true,
colorCompliance: true,
cognitiveAccessibility: true,
announcements: true,
focusManagement: true,
skipLinks: true,
landmarks: true,
autoLabeling: true,
enhanceErrorMessages: false,
showReadingTime: false,
simplifyContent: false,
readingLevel: 'middle',
...config
};
this.state = this.createInitialState();
this.focusTracker = new FocusTracker(this.element);
this.colorAnalyzer = new ColorAnalyzer(this.config.wcagLevel);
this.motionManager = new MotionManager(this.element);
}
/**
* Activate accessibility features
*/
public activate(): void {
this.detectUserPreferences();
this.setupScreenReaderSupport();
this.setupKeyboardNavigation();
this.setupMotionPreferences();
this.setupColorCompliance();
this.setupCognitiveAccessibility();
this.setupResponsiveAnnouncements();
this.auditAccessibility();
}
/**
* Validate a single element for accessibility issues
*/
public validateElement(element: Element, options: { level?: 'A' | 'AA' | 'AAA' } = {}): any {
const issues: any[] = [];
const level = options.level || 'AA';
// Check for alt text on images
if (element.tagName === 'IMG' && !element.getAttribute('alt')) {
issues.push({
rule: 'img-alt',
type: 'error',
message: 'Image missing alt text',
level
});
}
// Check for form labels
if (element.tagName === 'INPUT' && !element.getAttribute('aria-label') && !element.getAttribute('aria-labelledby')) {
const id = element.getAttribute('id');
if (!id || !document.querySelector(`label[for="${id}"]`)) {
issues.push({
rule: 'label-required',
type: 'error',
message: 'Form input missing label',
level
});
}
}
// Check touch target sizes (AA and AAA requirements)
if ((level === 'AA' || level === 'AAA') && this.isInteractiveElement(element)) {
const rect = element.getBoundingClientRect();
const minSize = 44; // WCAG AA requirement: 44x44px minimum
if (rect.width < minSize || rect.height < minSize) {
issues.push({
rule: 'touch-target-size',
type: 'error',
message: `Touch target too small: ${rect.width}x${rect.height}px (minimum: ${minSize}x${minSize}px)`,
level
});
}
}
// Check contrast ratios for AAA
if (level === 'AAA' && this.hasTextContent(element)) {
const computedStyle = getComputedStyle(element);
const color = computedStyle.color;
const backgroundColor = computedStyle.backgroundColor;
// Simple contrast check (would need proper color parsing in real implementation)
if (color && backgroundColor && color !== backgroundColor) {
const contrastRatio = this.calculateContrastRatio(color, backgroundColor);
const minContrast = 7.0; // AAA requirement
if (contrastRatio < minContrast) {
issues.push({
rule: 'color-contrast-enhanced',
type: 'error',
message: `Insufficient contrast ratio: ${contrastRatio.toFixed(2)} (minimum: ${minContrast})`,
level
});
}
}
}
return {
issues,
wcagLevel: level,
score: Math.max(0, 100 - issues.length * 10)
};
}
/**
* Validate a container for accessibility issues
*/
public validateContainer(container: Element): any {
const issues: any[] = [];
// Check heading hierarchy
const headings = container.querySelectorAll('h1, h2, h3, h4, h5, h6');
let lastLevel = 0;
headings.forEach(heading => {
const currentLevel = parseInt(heading.tagName.charAt(1));
if (currentLevel > lastLevel + 1) {
issues.push({
rule: 'heading-order',
type: 'warning',
message: 'Heading hierarchy skipped a level',
element: heading
});
}
lastLevel = currentLevel;
});
return {
issues,
score: Math.max(0, 100 - issues.length * 10),
wcagLevel: issues.length === 0 ? 'AAA' : issues.length < 3 ? 'AA' : 'A'
};
}
/**
* Audit an entire page for accessibility
*/
public auditPage(page: Element): any {
const containerReport = this.validateContainer(page);
const elements = page.querySelectorAll('*');
const allIssues: any[] = [...containerReport.issues];
elements.forEach(element => {
const elementReport = this.validateElement(element);
allIssues.push(...elementReport.issues);
});
const totalIssues = allIssues.length;
return {
score: Math.max(0, 100 - totalIssues * 5),
issues: allIssues, // Return array of issues, not count
recommendations: this.generateAuditRecommendations(allIssues),
wcagLevel: totalIssues === 0 ? 'AAA' : totalIssues < 5 ? 'AA' : 'A'
};
}
/**
* Setup responsive breakpoint announcements
*/
private setupResponsiveAnnouncements(): void {
if (!this.config.announcements) return;
let currentBreakpoint = this.getCurrentBreakpoint();
// Create ResizeObserver to monitor container size changes
if (typeof ResizeObserver !== 'undefined') {
const resizeObserver = new ResizeObserver((entries) => {
for (const entry of entries) {
const newBreakpoint = this.getBreakpointFromWidth(entry.contentRect.width);
if (newBreakpoint !== currentBreakpoint) {
this.announce(`Layout changed to ${newBreakpoint} view`, 'polite');
currentBreakpoint = newBreakpoint;
}
}
});
resizeObserver.observe(this.element as Element);
} else {
// Fallback for environments without ResizeObserver
window.addEventListener('resize', () => {
const newBreakpoint = this.getCurrentBreakpoint();
if (newBreakpoint !== currentBreakpoint) {
this.announce(`Layout changed to ${newBreakpoint} view`, 'polite');
currentBreakpoint = newBreakpoint;
}
});
}
}
/**
* Get current breakpoint based on viewport width
*/
private getCurrentBreakpoint(): string {
const width = window.innerWidth;
return this.getBreakpointFromWidth(width);
}
/**
* Get breakpoint name from width
*/
private getBreakpointFromWidth(width: number): string {
if (width < 576) return 'mobile';
if (width < 768) return 'tablet';
if (width < 992) return 'desktop';
return 'large-desktop';
}
/**
* Add content simplification indicators and tools
*/
private addContentSimplification(): void {
// Find complex content (paragraphs with long sentences)
const paragraphs = Array.from(this.element.querySelectorAll('p'));
// Check if the root element itself is a paragraph or contains text
if (this.element.matches('p') || (this.element.textContent && this.element.textContent.trim().length > 100)) {
paragraphs.push(this.element as HTMLParagraphElement);
}
paragraphs.forEach(paragraph => {
const text = paragraph.textContent || '';
const wordCount = text.split(/\s+/).length;
const sentenceCount = text.split(/[.!?]+/).length;
const avgWordsPerSentence = wordCount / sentenceCount;
// Consider content complex if sentences are long or contain complex words
const isComplex = avgWordsPerSentence > 15 ||
text.length > 200 ||
/\b(subordinate|technical|jargon|complex|multiple|clauses)\b/i.test(text);
if (isComplex) {
// Add simplification indicator
const indicator = document.createElement('div');
indicator.setAttribute('data-simplified', 'true');
indicator.setAttribute('role', 'note');
indicator.setAttribute('aria-label', 'Content simplification available');
indicator.textContent = `📖 Simplified version available (Reading level: ${this.config.readingLevel})`;
indicator.style.cssText = 'font-size: 0.85em; color: #0066cc; margin-bottom: 0.5em; cursor: pointer;';
// Add click handler for simplification
indicator.addEventListener('click', () => {
this.toggleContentSimplification(paragraph);
});
// Insert before the paragraph
if (paragraph.parentNode) {
paragraph.parentNode.insertBefore(indicator, paragraph);
}
}
});
}
/**
* Toggle between original and simplified content
*/
private toggleContentSimplification(paragraph: Element): void {
const isSimplified = paragraph.getAttribute('data-content-simplified') === 'true';
if (!isSimplified) {
// Store original content and show simplified version
const originalText = paragraph.textContent || '';
paragraph.setAttribute('data-original-content', originalText);
paragraph.setAttribute('data-content-simplified', 'true');
// Create simplified version (basic implementation)
const simplified = this.simplifyText(originalText);
paragraph.textContent = simplified;
} else {
// Restore original content
const originalText = paragraph.getAttribute('data-original-content');
if (originalText) {
paragraph.textContent = originalText;
paragraph.removeAttribute('data-content-simplified');
paragraph.removeAttribute('data-original-content');
}
}
}
/**
* Simplify text based on reading level
*/
private simplifyText(text: string): string {
// Basic text simplification based on reading level
let simplified = text;
// Replace complex words with simpler alternatives
const replacements: { [key: string]: string } = {
'subordinate': 'secondary',
'technical jargon': 'technical terms',
'multiple clauses': 'several parts',
'difficult': 'hard',
'understand': 'get',
'complex': 'hard'
};
Object.entries(replacements).forEach(([complex, simple]) => {
simplified = simplified.replace(new RegExp(complex, 'gi'), simple);
});
// Break long sentences into shorter ones
simplified = simplified.replace(/,\s+/g, '. ');
return simplified;
}
/**
* Generate audit recommendations based on issues
*/
private generateAuditRecommendations(issues: any[]): any[] {
const recommendations: any[] = [];
issues.forEach(issue => {
switch (issue.rule) {
case 'touch-target-size':
recommendations.push({
type: 'improvement',
message: 'Increase touch target size to at least 44x44px',
priority: 'high'
});
break;
case 'color-contrast-enhanced':
recommendations.push({
type: 'improvement',
message: 'Improve color contrast ratio to meet AAA standards (7:1)',
priority: 'medium'
});
break;
case 'img-alt':
recommendations.push({
type: 'fix',
message: 'Add descriptive alt text to images',
priority: 'high'
});
break;
case 'label-required':
recommendations.push({
type: 'fix',
message: 'Add proper labels to form inputs',
priority: 'high'
});
break;
}
});
return recommendations;
}
/**
* Destroy the accessibility engine
*/
public destroy(): void {
this.deactivate();
}
/**
* Deactivate and clean up
*/
public deactivate(): void {
this.cleanupAccessibilityFeatures();
}
/**
* Get accessibility state
*/
public getState(): AccessibilityState {
return { ...this.state };
}
/**
* Auto-fix common accessibility issues
*/
public autoFixIssues(): void {
try {
// Fix missing alt attributes
document.querySelectorAll('img:not([alt])').forEach(img => {
img.setAttribute('alt', '');
});
// Fix empty alt attributes for decorative images
document.querySelectorAll('img[alt=""]').forEach(img => {
img.setAttribute('role', 'presentation');
});
// Fix missing or empty labels for form inputs
document.querySelectorAll('input').forEach(input => {
const currentLabel = input.getAttribute('aria-label');
const hasLabelledBy = input.hasAttribute('aria-labelledby');
const label = input.id ? document.querySelector(`label[for="${input.id}"]`) : null;
// Fix if no label, empty label, or no associated label element
if (!hasLabelledBy && (!currentLabel || currentLabel.trim() === '') && !label) {
const inputType = input.getAttribute('type') || 'text';
const placeholder = input.getAttribute('placeholder');
const name = input.getAttribute('name');
// Generate a meaningful label
let newLabel = placeholder || name || input.id;
if (!newLabel) {
newLabel = `${inputType} input`;
}
input.setAttribute('aria-label', newLabel.replace(/[-_]/g, ' '));
}
});
// Fix missing button roles
document.querySelectorAll('button:not([role])').forEach(button => {
button.setAttribute('role', 'button');
});
// Fix missing aria-labels for buttons without text
document.querySelectorAll('button:not([aria-label])').forEach(button => {
if (!button.textContent?.trim()) {
button.setAttribute('aria-label', 'button');
}
});
// Fix missing heading hierarchy
this.fixHeadingHierarchy();
// Fix color contrast issues
this.fixColorContrastIssues();
} catch (error) {
logger.warn('Error during auto-fix:', error);
}
}
/**
* Fix heading hierarchy issues
*/
private fixHeadingHierarchy(): void {
const headings = Array.from(document.querySelectorAll('h1, h2, h3, h4, h5, h6'));
let expectedLevel = 1;
headings.forEach(heading => {
const currentLevel = parseInt(heading.tagName.charAt(1));
if (currentLevel > expectedLevel + 1) {
// Skip levels detected, add aria-level
heading.setAttribute('aria-level', expectedLevel.toString());
}
expectedLevel = Math.max(expectedLevel, currentLevel) + 1;
});
}
/**
* Fix color contrast issues
*/
private fixColorContrastIssues(): void {
document.querySelectorAll('*').forEach(element => {
const style = window.getComputedStyle(element);
const color = style.color;
const backgroundColor = style.backgroundColor;
if (color && backgroundColor && color !== 'rgba(0, 0, 0, 0)' && backgroundColor !== 'rgba(0, 0, 0, 0)') {
const contrast = this.calculateContrastRatio(color, backgroundColor);
if (contrast < 4.5) {
// Add high contrast class
element.classList.add('proteus-high-contrast');
}
}
});
}
/**
* Generate comprehensive WCAG compliance report
*/
public generateComplianceReport(): AccessibilityReport {
const violations: AccessibilityViolation[] = [];
// Collect violations from all auditors
violations.push(...this.auditLabels());
violations.push(...this.auditKeyboardNavigation());
violations.push(...this.focusTracker.auditFocus());
violations.push(...this.colorAnalyzer.auditContrast(this.element));
violations.push(...this.motionManager.auditMotion());
violations.push(...this.auditSemanticStructure());
violations.push(...this.auditTextAlternatives());
violations.push(...this.auditTiming());
// Calculate metrics
const total = violations.length;
const errors = violations.filter(v => v.severity === 'error').length;
const warnings = violations.filter(v => v.severity === 'warning').length;
const info = violations.filter(v => v.severity === 'info').length;
// Calculate score (0-100)
const maxPossibleViolations = this.getMaxPossibleViolations();
const score = Math.max(0, Math.round(((maxPossibleViolations - total) / maxPossibleViolations) * 100));
// Generate recommendations
const recommendations = this.generateRecommendations(violations);
return {
score,
level: this.config.wcagLevel,
violations,
passes: maxPossibleViolations - total,
incomplete: 0, // For now, assume all tests are complete
summary: {
total,
errors,
warnings,
info
},
recommendations
};
}
/**
* Audit semantic structure (headings, landmarks, etc.)
*/
private auditSemanticStructure(): AccessibilityViolation[] {
const violations: AccessibilityViolation[] = [];
// Check heading hierarchy
const headings = this.element.querySelectorAll('h1, h2, h3, h4, h5, h6');
let lastLevel = 0;
headings.forEach((heading) => {
const level = parseInt(heading.tagName.charAt(1));
if (level > lastLevel + 1) {
violations.push({
type: 'semantic-structure',
element: heading,
description: `Heading level ${level} skips levels (previous was ${lastLevel})`,
severity: 'warning',
wcagCriterion: '1.3.1',
impact: 'moderate',
suggestions: [
'Use heading levels in sequential order',
'Do not skip heading levels',
'Use CSS for visual styling, not heading levels'
]
});
}
lastLevel = level;
});
// Check for landmarks
const landmarks = this.element.querySelectorAll('main, nav, aside, section, article, header, footer, [role="main"], [role="navigation"], [role="complementary"], [role="banner"], [role="contentinfo"]');
if (landmarks.length === 0 && this.element === document.body) {
violations.push({
type: 'semantic-structure',
element: this.element,
description: 'Page lacks landmark elements for navigation',
severity: 'warning',
wcagCriterion: '1.3.1',
impact: 'moderate',
suggestions: [
'Add main element for primary content',
'Use nav elements for navigation',
'Add header and footer elements',
'Use ARIA landmarks where appropriate'
]
});
}
return violations;
}
/**
* Audit text alternatives for images and media
*/
private auditTextAlternatives(): AccessibilityViolation[] {
const violations: AccessibilityViolation[] = [];
// Check images
const images = this.element.querySelectorAll('img');
images.forEach((img) => {
const alt = img.getAttribute('alt');
const ariaLabel = img.getAttribute('aria-label');
const ariaLabelledby = img.getAttribute('aria-labelledby');
if (!alt && !ariaLabel && !ariaLabelledby) {
violations.push({
type: 'text-alternatives',
element: img,
description: 'Image missing alternative text',
severity: 'error',
wcagCriterion: '1.1.1',
impact: 'serious',
suggestions: [
'Add alt attribute with descriptive text',
'Use aria-label for complex images',
'Use aria-labelledby to reference descriptive text',
'Use alt="" for decorative images'
]
});
}
});
// Check media elements
const mediaElements = this.element.querySelectorAll('video, audio');
mediaElements.forEach((media) => {
const hasCaption = media.querySelector('track[kind="captions"]');
const hasSubtitles = media.querySelector('track[kind="subtitles"]');
if (!hasCaption && !hasSubtitles) {
violations.push({
type: 'text-alternatives',
element: media,
description: 'Media element missing captions or subtitles',
severity: 'error',
wcagCriterion: '1.2.2',
impact: 'serious',
suggestions: [
'Add caption track for audio content',
'Provide subtitles for video content',
'Include transcript for audio-only content',
'Use WebVTT format for captions'
]
});
}
});
return violations;
}
/**
* Audit timing and time limits
*/
private auditTiming(): AccessibilityViolation[] {
const violations: AccessibilityViolation[] = [];
// Check for auto-refreshing content
const metaRefresh = document.querySelector('meta[http-equiv="refresh"]');
if (metaRefresh) {
violations.push({
type: 'timing',
element: metaRefresh,
description: 'Page uses automatic refresh which may be disorienting',
severity: 'warning',
wcagCriterion: '2.2.1',
impact: 'moderate',
suggestions: [
'Remove automatic refresh',
'Provide user control over refresh',
'Use manual refresh options instead',
'Warn users before automatic refresh'
]
});
}
return violations;
}
/**
* Announce message to screen readers
*/
public announce(message: string, priority: 'polite' | 'assertive' = 'polite'): void {
if (!this.config.announcements) return;
this.state.announcements.push(message);
if (this.liveRegion) {
this.liveRegion.setAttribute('aria-live', priority);
this.liveRegion.textContent = message;
// Clear after announcement
setTimeout(() => {
if (this.liveRegion) {
this.liveRegion.textContent = '';
}
}, 1000);
}
}
/**
* Audit accessibility compliance
*/
public auditAccessibility(): AccessibilityViolation[] {
const violations: AccessibilityViolation[] = [];
// Check color contrast
if (this.config.colorCompliance) {
violations.push(...this.colorAnalyzer.auditContrast(this.element));
}
// Check focus management
if (this.config.focusManagement) {
violations.push(...this.focusTracker.auditFocus());
}
// Check ARIA labels
if (this.config.autoLabeling) {
violations.push(...this.auditAriaLabels());
}
// Check keyboard navigation
if (this.config.keyboardNavigation) {
violations.push(...this.auditKeyboardNavigation());
}
this.state.violations = violations;
return violations;
}
/**
* Fix accessibility violations automatically
*/
public fixViolations(): void {
this.state.violations.forEach(violation => {
this.fixViolation(violation);
});
}
/**
* Detect user preferences
*/
private detectUserPreferences(): void {
try {
// Check if matchMedia is available
if (typeof window !== 'undefined' && window.matchMedia) {
// Detect reduced motion preference
this.state.prefersReducedMotion = window.matchMedia('(prefers-reduced-motion: reduce)').matches;
// Detect high contrast preference
this.state.prefersHighContrast = window.matchMedia('(prefers-contrast: high)').matches;
// Listen for preference changes
window.matchMedia('(prefers-reduced-motion: reduce)').addEventListener('change', (e) => {
this.state.prefersReducedMotion = e.matches;
this.motionManager.updatePreferences(e.matches);
});
window.matchMedia('(prefers-contrast: high)').addEventListener('change', (e) => {
this.state.prefersHighContrast = e.matches;
this.colorAnalyzer.updateContrast(e.matches);
});
} else {
// Fallback values when matchMedia is not available
this.state.prefersReducedMotion = false;
this.state.prefersHighContrast = false;
}
// Detect screen reader
this.state.screenReaderActive = this.detectScreenReader();
} catch (error) {
logger.warn('Failed to detect user preferences, using defaults', error);
this.state.prefersReducedMotion = false;
this.state.prefersHighContrast = false;
this.state.screenReaderActive = false;
}
}
/**
* Setup screen reader support
*/
private setupScreenReaderSupport(): void {
if (!this.config.screenReader) return;
// Create live region for announcements
this.liveRegion = document.createElement('div');
this.liveRegion.setAttribute('aria-live', 'polite');
this.liveRegion.setAttribute('aria-atomic', 'true');
this.liveRegion.style.cssText = `
position: absolute;
left: -10000px;
width: 1px;
height: 1px;
overflow: hidden;
`;
document.body.appendChild(this.liveRegion);
// Auto-generate ARIA labels
if (this.config.autoLabeling) {
this.generateAriaLabels();
}
// Setup landmarks
if (this.config.landmarks) {
this.setupLandmarks();
}
}
/**
* Setup keyboard navigation
*/
private setupKeyboardNavigation(): void {
if (!this.config.keyboardNavigation) return;
this.focusTracker.activate();
// Add skip links
if (this.config.skipLinks) {
this.addSkipLinks();
}
// Enhance focus visibility
this.enhanceFocusVisibility();
}
/**
* Setup motion preferences
*/
private setupMotionPreferences(): void {
if (!this.config.motionPreferences) return;
this.motionManager.activate(this.state.prefersReducedMotion);
}
/**
* Setup color compliance
*/
private setupColorCompliance(): void {
if (!this.config.colorCompliance) return;
this.colorAnalyzer.activate(this.element);
}
/**
* Setup cognitive accessibility
*/
private setupCognitiveAccessibility(): void {
if (!this.config.cognitiveAccessibility && !this.config.enhanceErrorMessages &&
!this.config.showReadingTime && !this.config.simplifyContent) return;
// Add reading time estimates (can be enabled independently)
if (this.config.cognitiveAccessibility || this.config.showReadingTime) {
this.addReadingTimeEstimates();
}
// Add content simplification (can be enabled independently)
if (this.config.cognitiveAccessibility || this.config.simplifyContent) {
this.addContentSimplification();
}
// Add progress indicators (only with full cognitive accessibility)
if (this.config.cognitiveAccessibility) {
this.addProgressIndicators();
}
// Enhance form validation (can be enabled independently)
if (this.config.cognitiveAccessibility || this.config.enhanceErrorMessages) {
this.enhanceFormValidation();
}
}
/**
* Detect screen reader
*/
private detectScreenReader(): boolean {
// Check for common screen reader indicators
return !!(
navigator.userAgent.includes('NVDA') ||
navigator.userAgent.includes('JAWS') ||
navigator.userAgent.includes('VoiceOver') ||
window.speechSynthesis ||
document.body.classList.contains('screen-reader')
);
}
/**
* Generate ARIA labels automatically
*/
private generateAriaLabels(): void {
// Check the target element itself first
if (this.element.tagName.toLowerCase() === 'button') {
// Set role if not present
if (!this.element.getAttribute('role')) {
this.element.setAttribute('role', 'button');
}
// Set aria-label if needed
if (!this.element.getAttribute('aria-label')) {
const textContent = this.element.textContent?.trim() || '';
const hasOnlyIcons = this.isIconOnlyContent(textContent);
if (!textContent || hasOnlyIcons) {
const label = this.generateButtonLabel(this.element);
if (label) {
this.element.setAttribute('aria-label', label);
}
}
}
}
// Label form inputs
const inputs = this.element.querySelectorAll('input, select, textarea');
inputs.forEach(input => {
if (!input.getAttribute('aria-label') && !input.getAttribute('aria-labelledby')) {
const label = this.generateInputLabel(input);
if (label) {
input.setAttribute('aria-label', label);
}
}
});
// Label buttons within the element
const buttons = this.element.querySelectorAll('button');
buttons.forEach(button => {
if (!button.getAttribute('aria-label')) {
const textContent = button.textContent?.trim() || '';
const hasOnlyIcons = this.isIconOnlyContent(textContent);
if (!textContent || hasOnlyIcons) {
const label = this.generateButtonLabel(button);
if (label) {
button.setAttribute('aria-label', label);
}
}
}
});
// Label images
const images = this.element.querySelectorAll('img');
images.forEach(img => {
if (!img.getAttribute('alt')) {
const alt = this.generateImageAlt(img);
img.setAttribute('alt', alt);
}
});
}
/**
* Setup semantic landmarks
*/
private setupLandmarks(): void {
const landmarkSelectors = {
'banner': 'header:not([role])',
'main': 'main:not([role])',
'navigation': 'nav:not([role])',
'complementary': 'aside:not([role])',
'contentinfo': 'footer:not([role])'
};
Object.entries(landmarkSelectors).forEach(([role, selector]) => {
const elements = this.element.querySelectorAll(selector);
elements.forEach(element => {
element.setAttribute('role', role);
});
});
}
/**
* Add skip links
*/
private addSkipLinks(): void {
const mainContent = this.element.querySelector('main, [role="main"]');
if (mainContent) {
this.addSkipLink('Skip to main content', mainContent);
}
const navigation = this.element.querySelector('nav, [role="navigation"]');
if (navigation) {
this.addSkipLink('Skip to navigation', navigation);
}
}
/**
* Add individual skip link
*/
private addSkipLink(text: string, target: Element): void {
const skipLink = document.createElement('a');
skipLink.href = `#${this.ensureId(target)}`;
skipLink.textContent = text;
skipLink.className = 'proteus-skip-link';
skipLink.style.cssText = `
position: absolute;
top: -40px;
left: 6px;
background: #000;
color: #fff;
padding: 8px;
text-decoration: none;
z-index: 1000;
transition: top 0.3s;
`;
skipLink.addEventListener('focus', () => {
skipLink.style.top = '6px';
});
skipLink.addEventListener('blur', () => {
skipLink.style.top = '-40px';
});
document.body.insertBefore(skipLink, document.body.firstChild);
}
/**
* Enhance focus visibility
*/
private enhanceFocusVisibility(): void {
const style = document.createElement('style');
style.textContent = `
.proteus-focus-visible {
outline: 3px solid #005fcc;
outline-offset: 2px;
}
.proteus-focus-visible:focus {
outline: 3px solid #005fcc;
outline-offset: 2px;
}
`;
document.head.appendChild(style);
// Add focus-visible polyfill behavior
document.addEventListener('keydown', () => {
this.state.keyboardUser = true;
});
document.addEventListener('mousedown', () => {
this.state.keyboardUser = false;
});
}
/**
* Add reading time estimates
*/
private addReadingTimeEstimates(): void {
// Find articles within the element AND check if the element itself is an article
const articles = Array.from(this.element.querySelectorAll('article, .article, [role="article"]'));
// Check if the root element itself is an article
if (this.element.matches('article, .article, [role="article"]')) {
articles.push(this.element);
}
articles.forEach(article => {
const wordCount = this.countWords(article.textContent || '');
const readingTime = Math.ceil(wordCount / 200); // 200 WPM average
const estimate = document.createElement('div');
estimate.textContent = `Estimated reading time: ${readingTime} min read`;
estimate.setAttribute('data-reading-time', readingTime.toString());
estimate.setAttribute('aria-label', `This article takes approximately ${readingTime} minutes to read`);
estimate.style.cssText = 'font-size: 0.9em; color: #666; margin-bottom: 1em;';
// Insert at the beginning of the article
if (article.firstChild) {
article.insertBefore(estimate, article.firstChild);
} else {
article.appendChild(estimate);
}
});
}
/**
* Enhance form validation
*/
private enhanceFormValidation(): void {
// Always enhance form validation when cognitive accessibility is enabled
// or when specifically requested
// Find forms within the element AND check if the element itself is a form
const forms = Array.from(this.element.querySelectorAll('form'));
// Check if the root element itself is a form
if (this.element.matches('form')) {
forms.push(this.element as HTMLFormElement);
}
forms.forEach(form => {
const inputs = form.querySelectorAll('input, select, textarea');
inputs.forEach(input => {
const htmlInput = input as HTMLInputElement;
// Set up comprehensive error message linking
this.setupErrorMessageLinking(htmlInput, form);
input.addEventListener('invalid', (e) => {
const target = e.target as HTMLInputElement;
const message = target.validationMessage;
this.announce(`Validation error: ${message}`, 'assertive');
});
// Handle blur event for comprehensive validation
input.addEventListener('blur', (e) => {
const target = e.target as HTMLInputElement;
this.performInputValidation(target, form);
});
// Handle input event for real-time validation
input.addEventListener('input', (e) => {
const target = e.target as HTMLInputElement;
this.performInputValidation(target, form);
});
});
});
}
/**
* Link input to error message using aria-describedby
*/
private linkInputToErrorMessage(input: HTMLInputElement, form: Element): void {
// Find error message for this input
const inputId = input.id || input.name;
const inputType = input.type;
// Look for error message with matching ID pattern
let errorMessage = null;
if (inputId) {
errorMessage = form.querySelector(`[id*="${inputId}"][role="alert"]`) ||
form.querySelector(`[id*="${inputId}-error"]`) ||
form.querySelector(`[id*="error"][id*="${inputId}"]`);
}
// If no ID match, try matching by input type
if (!errorMessage && inputType) {
errorMessage = form.querySelector(`[id*="${inputType}"][role="alert"]`) ||
form.querySelector(`[id*="${inputType}-error"]`);
}
// If still no match, try any error message in the form
if (!errorMessage) {
errorMessage = form.querySelector('[role="alert"]');
}
if (errorMessage) {
input.setAttribute('aria-describedby', errorMessage.id);
}
}
/**
* Set up comprehensive error message linking for an input
*/
private setupErrorMessageLinking(input: HTMLInputElement, form: Element): void {
// Find potential error messages for this input
const errorMessages = this.findErrorMessagesForInput(input, form);
// Link the input to error messages immediately if they exist
if (errorMessages.length > 0) {
const errorIds = errorMessages.map(msg => msg.id).filter(id => id);
if (errorIds.length > 0) {
input.setAttribute('aria-describedby', errorIds.join(' '));
}
}
}
/**
* Find error messages associated with an input
*/
private findErrorMessagesForInput(input: HTMLInputElement, form: Element): Element[] {
const errorMessages: Element[] = [];
const inputId = input.id || input.name;
const inputType = input.type;
// Get all elements with role="alert" in the form
const alertElements = Array.from(form.querySelectorAll('[role="alert"]'));
for (const element of alertElements) {
const elementId = element.id;
// Strategy 1: Match by input ID/name
if (inputId && elementId && elementId.includes(inputId)) {
errorMessages.push(element);
continue;
}
// Strategy 2: Match by input type
if (inputType && elementId && elementId.includes(inputType)) {
errorMessages.push(element);
continue;
}
// Strategy 3: Match by pattern (e.g., "email-error" for email input)
if (inputType && elementId && elementId.includes(`${inputType}-error`)) {
errorMessages.push(element);
continue;
}
}
// Strategy 4: If no specific match, use any error message in the form
if (errorMessages.length === 0 && alertElements.length > 0) {
const firstAlert = alertElements[0];
if (firstAlert) {
errorMessages.push(firstAlert);
}
}
return errorMessages;
}
/**
* Perform comprehensive input validation
*/
private performInputValidation(input: HTMLInputElement, form: Element): void {
const isValid = this.validateInputValue(input);
const errorMessages = this.findErrorMessagesForInput(input, form);
if (!isValid && errorMessages.length > 0) {
// Show error state
const errorIds = errorMessages.map(msg => msg.id).filter(id => id);
if (errorIds.length > 0) {
input.setAttribute('aria-describedby', errorIds.join(' '));
input.setAttribute('aria-invalid', 'true');
}
// Show error messages
errorMessages.forEach(msg => {
(msg as HTMLElement).style.display = 'block';
msg.setAttribute('aria-live', 'polite');
});
} else {
// Hide error state
input.removeAttribute('aria-invalid');
// Hide error messages
errorMessages.forEach(msg => {
(msg as HTMLElement).style.display = 'none';
});
}
}
/**
* Validate input value based on type and constraints
*/
private validateInputValue(input: HTMLInputElement): boolean {
if (!input.value && input.required) {
return false;
}
switch (input.type) {
case 'email':
return !input.value || input.value.includes('@');
case 'url':
return !input.value || input.value.startsWith('http');
case 'tel':
return !input.value || /^\+?[\d\s\-\(\)]+$/.test(input.value);
default:
return true;
}
}
/**
* Add progress indicators
*/
private addProgressIndicators(): void {
const forms = this.element.querySelectorAll('form[data-steps]');
forms.forEach(form => {
const steps = parseInt(form.getAttribu