Debugging and Troubleshooting Polyfills

// devtools-helpers.js
var PolyfillDebugger = {
    // Check if polyfill is loaded
    isPolyfillLoaded: function(featureName) {
        var polyfillMarkers = {
            'Promise': function() {
                return window.Promise && Promise.toString().indexOf('[native code]') === -1;
            },
            'fetch': function() {
                return window.fetch && fetch.polyfill === true;
            },
            'IntersectionObserver': function() {
                return window.IntersectionObserver && 
                       IntersectionObserver.toString().indexOf('[native code]') === -1;
            }
        };
        
        var checker = polyfillMarkers[featureName];
        return checker ? checker() : false;
    },
    
    // List all loaded polyfills
    listLoadedPolyfills: function() {
        var polyfills = [];
        var features = [
            'Promise', 'fetch', 'Map', 'Set', 'WeakMap', 'WeakSet',
            'Symbol', 'Array.from', 'Object.assign', 'IntersectionObserver',
            'ResizeObserver', 'requestAnimationFrame', 'CustomEvent'
        ];
        
        features.forEach(function(feature) {
            if (this.isPolyfillLoaded(feature)) {
                polyfills.push(feature);
            }
        }.bind(this));
        
        console.table(polyfills.map(function(name) {
            return { Feature: name, Polyfilled: '✓' };
        }));
        
        return polyfills;
    },
    
    // Set breakpoint on polyfill
    breakOnPolyfill: function(methodName) {
        var original = window[methodName];
        
        if (!original) {
            console.error('Method not found:', methodName);
            return;
        }
        
        window[methodName] = function() {
            debugger; // Breakpoint here
            return original.apply(this, arguments);
        };
        
        console.log('Breakpoint set on:', methodName);
    },
    
    // Trace polyfill calls
    tracePolyfill: function(obj, methodName) {
        var original = obj[methodName];
        
        if (!original) {
            console.error('Method not found:', methodName);
            return;
        }
        
        obj[methodName] = function() {
            console.group('Polyfill Call: ' + methodName);
            console.log('Arguments:', arguments);
            console.trace('Call Stack');
            
            var result = original.apply(this, arguments);
            
            console.log('Return Value:', result);
            console.groupEnd();
            
            return result;
        };
        
        console.log('Tracing enabled for:', methodName);
    },
    
    // Inspect polyfill source
    inspectPolyfill: function(featureName) {
        var feature = window[featureName];
        
        if (!feature) {
            console.error('Feature not found:', featureName);
            return;
        }
        
        console.group('Polyfill Inspection: ' + featureName);
        console.log('Type:', typeof feature);
        console.log('Source:', feature.toString());
        console.log('Properties:', Object.getOwnPropertyNames(feature));
        
        // Check if native or polyfilled
        var isNative = feature.toString().indexOf('[native code]') !== -1;
        console.log('Native:', isNative);
        console.log('Polyfilled:', !isNative);
        
        console.groupEnd();
    },
    
    // Monitor polyfill performance
    monitorPerformance: function(obj, methodName, iterations) {
        iterations = iterations || 1000;
        
        var original = obj[methodName];
        if (!original) {
            console.error('Method not found:', methodName);
            return;
        }
        
        console.log('Benchmarking ' + methodName + ' (' + iterations + ' iterations)...');
        
        var start = performance.now();
        for (var i = 0; i < iterations; i++) {
            original.call(obj);
        }
        var end = performance.now();
        
        var duration = end - start;
        var avgTime = duration / iterations;
        
        console.log('Total Time: ' + duration.toFixed(2) + 'ms');
        console.log('Average Time: ' + avgTime.toFixed(4) + 'ms');
        console.log('Ops/Second: ' + (1000 / avgTime).toFixed(0));
    },
    
    // Check code coverage for polyfills
    checkCoverage: function() {
        console.log('Run this in Chrome DevTools:');
        console.log('1. Open Coverage tab (Cmd+Shift+P > "Show Coverage")');
        console.log('2. Click record button');
        console.log('3. Interact with your app');
        console.log('4. Click stop to see unused polyfills');
        console.log('5. Filter by "polyfill" to see polyfill coverage');
    },
    
    // Debug feature detection
    debugFeatureDetection: function() {
        var features = {
            'Promise': typeof Promise !== 'undefined',
            'fetch': typeof fetch !== 'undefined',
            'Map': typeof Map !== 'undefined',
            'Set': typeof Set !== 'undefined',
            'Symbol': typeof Symbol !== 'undefined',
            'Proxy': typeof Proxy !== 'undefined',
            'WeakMap': typeof WeakMap !== 'undefined',
            'IntersectionObserver': typeof IntersectionObserver !== 'undefined',
            'ResizeObserver': typeof ResizeObserver !== 'undefined',
            'CustomElements': typeof customElements !== 'undefined',
            'ShadowDOM': 'attachShadow' in Element.prototype,
            'ES6 Classes': (function() {
                try {
                    eval('class Test {}');
                    return true;
                } catch (e) {
                    return false;
                }
            })()
        };
        
        console.table(features);
        return features;
    }
};

// Console helpers - add to global scope for easy access
window.polyfillDebug = PolyfillDebugger;

// Usage examples:
// polyfillDebug.listLoadedPolyfills();
// polyfillDebug.breakOnPolyfill('fetch');
// polyfillDebug.tracePolyfill(Array.prototype, 'find');
// polyfillDebug.inspectPolyfill('Promise');
// polyfillDebug.monitorPerformance(Array.prototype, 'map', 10000);
// polyfillDebug.debugFeatureDetection();

// polyfill-troubleshooter.js
var PolyfillTroubleshooter = {
    // Diagnose polyfill issues
    diagnose: function() {
        var issues = [];
        
        // Check 1: Are polyfills loading?
        if (!this.checkPolyfillsLoaded()) {
            issues.push({
                severity: 'error',
                issue: 'Polyfills not loading',
                solution: 'Check network tab for failed requests'
            });
        }
        
        // Check 2: Are there conflicts?
        var conflicts = this.detectConflicts();
        if (conflicts.length > 0) {
            issues.push({
                severity: 'warning',
                issue: 'Polyfill conflicts detected',
                conflicts: conflicts,
                solution: 'Remove duplicate polyfills or adjust load order'
            });
        }
        
        // Check 3: Performance issues?
        var perfIssues = this.checkPerformance();
        if (perfIssues.length > 0) {
            issues.push({
                severity: 'warning',
                issue: 'Performance issues detected',
                details: perfIssues,
                solution: 'Consider lazy loading or optimizing polyfills'
            });
        }
        
        // Check 4: Memory leaks?
        this.checkMemoryLeaks().then(function(hasLeaks) {
            if (hasLeaks) {
                issues.push({
                    severity: 'error',
                    issue: 'Potential memory leak detected',
                    solution: 'Use Chrome DevTools Memory profiler'
                });
            }
        });
        
        // Check 5: CSP violations?
        if (this.checkCSPViolations()) {
            issues.push({
                severity: 'error',
                issue: 'CSP violations detected',
                solution: 'Use CSP-safe polyfills or adjust CSP headers'
            });
        }
        
        this.reportIssues(issues);
        return issues;
    },
    
    // Check if polyfills are loaded
    checkPolyfillsLoaded: function() {
        var scripts = document.querySelectorAll('script[src*="polyfill"]');
        
        if (scripts.length === 0) {
            console.warn('No polyfill scripts found');
            return false;
        }
        
        var allLoaded = true;
        scripts.forEach(function(script) {
            if (!script.complete || script.readyState === 'loading') {
                console.error('Polyfill not loaded:', script.src);
                allLoaded = false;
            }
        });
        
        return allLoaded;
    },
    
    // Detect polyfill conflicts
    detectConflicts: function() {
        var conflicts = [];
        
        // Check for duplicate polyfills
        var methods = [
            { obj: Array.prototype, name: 'find' },
            { obj: Array.prototype, name: 'includes' },
            { obj: Object, name: 'assign' },
            { obj: String.prototype, name: 'includes' }
        ];
        
        methods.forEach(function(method) {
            var descriptor = Object.getOwnPropertyDescriptor(method.obj, method.name);
            
            if (descriptor && descriptor.configurable === false) {
                // Check if it was polyfilled after being native
                var source = method.obj[method.name].toString();
                var isNative = source.indexOf('[native code]') !== -1;
                
                if (!isNative && !descriptor.configurable) {
                    conflicts.push({
                        method: method.name,
                        issue: 'Non-configurable polyfill override',
                        recommendation: 'Check polyfill load order'
                    });
                }
            }
        });
        
        return conflicts;
    },
    
    // Check performance issues
    checkPerformance: function() {
        var issues = [];
        
        // Check load time
        var resources = performance.getEntriesByType('resource');
        resources.forEach(function(resource) {
            if (resource.name.indexOf('polyfill') !== -1) {
                if (resource.duration > 500) {
                    issues.push({
                        file: resource.name,
                        issue: 'Slow loading (>500ms)',
                        duration: resource.duration.toFixed(2) + 'ms'
                    });
                }
                
                if (resource.transferSize > 100 * 1024) {
                    issues.push({
                        file: resource.name,
                        issue: 'Large file size (>100KB)',
                        size: (resource.transferSize / 1024).toFixed(2) + 'KB'
                    });
                }
            }
        });
        
        return issues;
    },
    
    // Check for memory leaks
    checkMemoryLeaks: function() {
        if (!performance.memory) {
            console.warn('performance.memory not available');
            return Promise.resolve(false);
        }
        
        var initialHeap = performance.memory.usedJSHeapSize;
        
        return new Promise(function(resolve) {
            setTimeout(function() {
                var currentHeap = performance.memory.usedJSHeapSize;
                var growth = currentHeap - initialHeap;
                var growthMB = growth / 1024 / 1024;
                
                if (growthMB > 10) {
                    console.warn('Significant memory growth detected: ' + 
                               growthMB.toFixed(2) + 'MB');
                    resolve(true);
                } else {
                    resolve(false);
                }
            }, 5000);
        });
    },
    
    // Check for CSP violations
    checkCSPViolations: function() {
        var hasViolations = false;
        
        // Listen for CSP violations
        document.addEventListener('securitypolicyviolation', function(e) {
            console.error('CSP Violation:', e.violatedDirective);
            hasViolations = true;
        });
        
        return hasViolations;
    },
    
    // Report all issues
    reportIssues: function(issues) {
        if (issues.length === 0) {
            console.log('✓ No polyfill issues detected');
            return;
        }
        
        console.group('Polyfill Issues Detected (' + issues.length + ')');
        
        issues.forEach(function(issue, index) {
            var icon = issue.severity === 'error' ? '❌' : '⚠️';
            console.group(icon + ' Issue ' + (index + 1) + ': ' + issue.issue);
            console.log('Severity:', issue.severity);
            console.log('Solution:', issue.solution);
            
            if (issue.conflicts) {
                console.log('Conflicts:', issue.conflicts);
            }
            if (issue.details) {
                console.table(issue.details);
            }
            
            console.groupEnd();
        });
        
        console.groupEnd();
    },
    
    // Fix common issues automatically
    autoFix: function() {
        console.log('Attempting automatic fixes...');
        
        // Fix 1: Remove duplicate polyfills
        this.removeDuplicatePolyfills();
        
        // Fix 2: Optimize polyfill loading
        this.optimizeLoading();
        
        console.log('Auto-fix complete. Run diagnose() to verify.');
    },
    
    // Remove duplicate polyfills
    removeDuplicatePolyfills: function() {
        var scripts = document.querySelectorAll('script[src*="polyfill"]');
        var seen = {};
        
        scripts.forEach(function(script) {
            var src = script.src;
            if (seen[src]) {
                console.log('Removing duplicate polyfill:', src);
                script.remove();
            } else {
                seen[src] = true;
            }
        });
    },
    
    // Optimize polyfill loading
    optimizeLoading: function() {
        // Add async/defer to non-critical polyfills
        var scripts = document.querySelectorAll('script[src*="polyfill"]');
        
        scripts.forEach(function(script) {
            if (!script.async && !script.defer) {
                // Check if polyfill is critical
                var isCritical = script.src.includes('critical') || 
                                script.src.includes('core');
                
                if (!isCritical) {
                    script.defer = true;
                    console.log('Added defer to:', script.src);
                }
            }
        });
    }
};

// Quick diagnostic command
window.polyfillCheck = function() {
    return PolyfillTroubleshooter.diagnose();
};

// Usage:
// polyfillCheck(); // Run diagnostics
// PolyfillTroubleshooter.autoFix(); // Attempt automatic fixes

// performance-profiler.js
var PolyfillProfiler = {
    profiles: [],
    
    // Profile polyfill loading
    profileLoading: function(polyfillName, loadFn) {
        var startMark = 'polyfill-load-start-' + polyfillName;
        var endMark = 'polyfill-load-end-' + polyfillName;
        var measureName = 'polyfill-load-' + polyfillName;
        
        performance.mark(startMark);
        
        return Promise.resolve(loadFn()).then(function() {
            performance.mark(endMark);
            performance.measure(measureName, startMark, endMark);
            
            var measure = performance.getEntriesByName(measureName)[0];
            
            var profile = {
                name: polyfillName,
                type: 'loading',
                duration: measure.duration,
                timestamp: Date.now()
            };
            
            this.profiles.push(profile);
            
            console.log('Polyfill ' + polyfillName + ' loaded in ' + 
                       measure.duration.toFixed(2) + 'ms');
            
            return profile;
        }.bind(this));
    },
    
    // Profile method execution
    profileMethod: function(obj, methodName, iterations) {
        iterations = iterations || 10000;
        
        var method = obj[methodName];
        if (!method) {
            console.error('Method not found:', methodName);
            return;
        }
        
        // Warm up
        for (var i = 0; i < 100; i++) {
            method.call(obj, i);
        }
        
        // Profile
        var start = performance.now();
        
        for (var i = 0; i < iterations; i++) {
            method.call(obj, i);
        }
        
        var end = performance.now();
        var duration = end - start;
        var avgTime = duration / iterations;
        
        var profile = {
            name: methodName,
            type: 'execution',
            totalTime: duration,
            avgTime: avgTime,
            iterations: iterations,
            opsPerSecond: Math.round(1000 / avgTime)
        };
        
        this.profiles.push(profile);
        
        console.log('Method: ' + methodName);
        console.log('  Total: ' + duration.toFixed(2) + 'ms');
        console.log('  Average: ' + avgTime.toFixed(4) + 'ms');
        console.log('  Ops/sec: ' + profile.opsPerSecond.toLocaleString());
        
        return profile;
    },
    
    // Compare native vs polyfill performance
    comparePerformance: function(nativeFn, polyfillFn, testName, iterations) {
        iterations = iterations || 10000;
        
        console.group('Performance Comparison: ' + testName);
        
        // Profile native
        var nativeStart = performance.now();
        for (var i = 0; i < iterations; i++) {
            nativeFn();
        }
        var nativeDuration = performance.now() - nativeStart;
        
        // Profile polyfill
        var polyfillStart = performance.now();
        for (var i = 0; i < iterations; i++) {
            polyfillFn();
        }
        var polyfillDuration = performance.now() - polyfillStart;
        
        var slowdown = polyfillDuration / nativeDuration;
        var acceptable = slowdown < 2;
        
        console.log('Native: ' + nativeDuration.toFixed(2) + 'ms');
        console.log('Polyfill: ' + polyfillDuration.toFixed(2) + 'ms');
        console.log('Slowdown: ' + slowdown.toFixed(2) + 'x');
        console.log('Acceptable: ' + (acceptable ? '✓' : '✗'));
        
        console.groupEnd();
        
        return {
            test: testName,
            native: nativeDuration,
            polyfill: polyfillDuration,
            slowdown: slowdown,
            acceptable: acceptable
        };
    },
    
    // Profile FCP impact
    profileFCPImpact: function() {
        if (!PerformanceObserver) {
            console.warn('PerformanceObserver not available');
            return;
        }
        
        var observer = new PerformanceObserver(function(list) {
            list.getEntries().forEach(function(entry) {
                if (entry.name === 'first-contentful-paint') {
                    var fcp = entry.startTime;
                    
                    // Calculate polyfill impact
                    var polyfillMarks = performance.getEntriesByType('mark')
                        .filter(function(m) { return m.name.includes('polyfill'); });
                    
                    var polyfillTime = 0;
                    polyfillMarks.forEach(function(mark) {
                        var measure = performance.getEntriesByName(mark.name)[0];
                        if (measure && measure.startTime < fcp) {
                            polyfillTime += measure.duration || 0;
                        }
                    });
                    
                    var impact = (polyfillTime / fcp) * 100;
                    
                    console.log('FCP: ' + fcp.toFixed(2) + 'ms');
                    console.log('Polyfill Time: ' + polyfillTime.toFixed(2) + 'ms');
                    console.log('Impact: ' + impact.toFixed(1) + '%');
                    
                    this.profiles.push({
                        type: 'fcp-impact',
                        fcp: fcp,
                        polyfillTime: polyfillTime,
                        impact: impact
                    });
                }
            }.bind(this));
        }.bind(this));
        
        observer.observe({ entryTypes: ['paint'] });
    },
    
    // Generate comprehensive report
    generateReport: function() {
        console.group('📊 Polyfill Performance Report');
        
        // Group by type
        var byType = {};
        this.profiles.forEach(function(profile) {
            if (!byType[profile.type]) {
                byType[profile.type] = [];
            }
            byType[profile.type].push(profile);
        });
        
        // Loading performance
        if (byType.loading) {
            console.group('Loading Performance');
            var totalLoadTime = byType.loading.reduce(function(sum, p) {
                return sum + p.duration;
            }, 0);
            
            console.log('Total Load Time: ' + totalLoadTime.toFixed(2) + 'ms');
            console.table(byType.loading);
            console.groupEnd();
        }
        
        // Execution performance
        if (byType.execution) {
            console.group('Execution Performance');
            console.table(byType.execution.map(function(p) {
                return {
                    Method: p.name,
                    'Avg Time': p.avgTime.toFixed(4) + 'ms',
                    'Ops/sec': p.opsPerSecond.toLocaleString()
                };
            }));
            console.groupEnd();
        }
        
        // FCP impact
        if (byType['fcp-impact']) {
            console.group('FCP Impact');
            byType['fcp-impact'].forEach(function(p) {
                console.log('FCP: ' + p.fcp.toFixed(2) + 'ms');
                console.log('Polyfill Impact: ' + p.impact.toFixed(1) + '%');
            });
            console.groupEnd();
        }
        
        // Recommendations
        console.group('Recommendations');
        var recommendations = this.generateRecommendations(byType);
        recommendations.forEach(function(rec) {
            console.log(rec.icon + ' ' + rec.message);
        });
        console.groupEnd();
        
        console.groupEnd();
        
        return {
            profiles: this.profiles,
            summary: byType,
            recommendations: recommendations
        };
    },
    
    // Generate recommendations
    generateRecommendations: function(byType) {
        var recommendations = [];
        
        // Check loading time
        if (byType.loading) {
            var totalLoadTime = byType.loading.reduce(function(sum, p) {
                return sum + p.duration;
            }, 0);
            
            if (totalLoadTime > 100) {
                recommendations.push({
                    icon: '⚠️',
                    message: 'Total polyfill load time exceeds 100ms (' + 
                            totalLoadTime.toFixed(2) + 'ms). Consider lazy loading.'
                });
            }
        }
        
        // Check execution performance
        if (byType.execution) {
            byType.execution.forEach(function(profile) {
                if (profile.avgTime > 1) {
                    recommendations.push({
                        icon: '⚠️',
                        message: profile.name + ' is slow (>1ms). Optimize implementation.'
                    });
                }
            });
        }
        
        // Check FCP impact
        if (byType['fcp-impact']) {
            byType['fcp-impact'].forEach(function(profile) {
                if (profile.impact > 20) {
                    recommendations.push({
                        icon: '❌',
                        message: 'Polyfills delay FCP by ' + profile.impact.toFixed(1) + 
                                '%. Use differential serving.'
                    });
                }
            });
        }
        
        if (recommendations.length === 0) {
            recommendations.push({
                icon: '✓',
                message: 'All metrics within acceptable ranges'
            });
        }
        
        return recommendations;
    }
};

// Usage examples:
// Profile polyfill loading
PolyfillProfiler.profileLoading('Promise', function() {
    return import('es6-promise/auto');
});

// Profile method execution
PolyfillProfiler.profileMethod(Array.prototype, 'find', 10000);

// Compare native vs polyfill
if (Array.prototype.map) {
    var nativeMap = Array.prototype.map;
    var polyfillMap = function() { /* polyfill implementation */ };
    
    PolyfillProfiler.comparePerformance(
        function() { [1,2,3].map(function(x) { return x * 2; }); },
        function() { [1,2,3].map(function(x) { return x * 2; }); },
        'Array.map',
        10000
    );
}

// Monitor FCP impact
PolyfillProfiler.profileFCPImpact();

// Generate report after page load
window.addEventListener('load', function() {
    setTimeout(function() {
        PolyfillProfiler.generateReport();
    }, 2000);
});

// feature-detection-debugger.js
var FeatureDetector = {
    // Comprehensive feature check
    detectFeature: function(featureName) {
        var detectors = {
            'Promise': this.detectPromise.bind(this),
            'fetch': this.detectFetch.bind(this),
            'Map': this.detectMap.bind(this),
            'Set': this.detectSet.bind(this),
            'Symbol': this.detectSymbol.bind(this),
            'Proxy': this.detectProxy.bind(this),
            'IntersectionObserver': this.detectIntersectionObserver.bind(this),
            'CustomElements': this.detectCustomElements.bind(this)
        };
        
        var detector = detectors[featureName];
        
        if (!detector) {
            console.error('No detector for feature:', featureName);
            return null;
        }
        
        var result = detector();
        
        console.group('Feature Detection: ' + featureName);
        console.log('Exists:', result.exists);
        console.log('Native:', result.isNative);
        console.log('Working:', result.isWorking);
        console.log('Details:', result.details);
        console.groupEnd();
        
        return result;
    },
    
    // Detect Promise support
    detectPromise: function() {
        var exists = typeof Promise !== 'undefined';
        var isNative = exists && Promise.toString().indexOf('[native code]') !== -1;
        var isWorking = false;
        var details = {};
        
        if (exists) {
            try {
                var promise = new Promise(function(resolve) {
                    resolve('test');
                });
                
                isWorking = promise instanceof Promise;
                
                // Test Promise.all
                details.hasAll = typeof Promise.all === 'function';
                details.hasRace = typeof Promise.race === 'function';
                details.hasAllSettled = typeof Promise.allSettled === 'function';
                details.hasAny = typeof Promise.any === 'function';
            } catch (e) {
                details.error = e.message;
            }
        }
        
        return { exists: exists, isNative: isNative, isWorking: isWorking, details: details };
    },
    
    // Detect fetch support
    detectFetch: function() {
        var exists = typeof fetch !== 'undefined';
        var isNative = exists && fetch.toString().indexOf('[native code]') !== -1;
        var isWorking = false;
        var details = {};
        
        if (exists) {
            try {
                // Check if fetch returns a Promise
                var result = fetch('data:text/plain,test');
                isWorking = result instanceof Promise;
                result.catch(function() {}); // Prevent unhandled rejection
                
                details.hasAbortController = typeof AbortController !== 'undefined';
                details.hasHeaders = typeof Headers !== 'undefined';
                details.hasRequest = typeof Request !== 'undefined';
                details.hasResponse = typeof Response !== 'undefined';
            } catch (e) {
                details.error = e.message;
            }
        }
        
        return { exists: exists, isNative: isNative, isWorking: isWorking, details: details };
    },
    
    // Detect Map support
    detectMap: function() {
        var exists = typeof Map !== 'undefined';
        var isNative = exists && Map.toString().indexOf('[native code]') !== -1;
        var isWorking = false;
        var details = {};
        
        if (exists) {
            try {
                var map = new Map();
                map.set('key', 'value');
                
                isWorking = map.get('key') === 'value' && map.size === 1;
                
                // Test iterator
                details.hasIterator = typeof map[Symbol.iterator] === 'function';
                details.hasForEach = typeof map.forEach === 'function';
            } catch (e) {
                details.error = e.message;
            }
        }
        
        return { exists: exists, isNative: isNative, isWorking: isWorking, details: details };
    },
    
    // Detect Set support
    detectSet: function() {
        var exists = typeof Set !== 'undefined';
        var isNative = exists && Set.toString().indexOf('[native code]') !== -1;
        var isWorking = false;
        var details = {};
        
        if (exists) {
            try {
                var set = new Set();
                set.add('value');
                
                isWorking = set.has('value') && set.size === 1;
                
                details.hasIterator = typeof set[Symbol.iterator] === 'function';
                details.hasForEach = typeof set.forEach === 'function';
            } catch (e) {
                details.error = e.message;
            }
        }
        
        return { exists: exists, isNative: isNative, isWorking: isWorking, details: details };
    },
    
    // Detect Symbol support
    detectSymbol: function() {
        var exists = typeof Symbol !== 'undefined';
        var isNative = exists && Symbol.toString().indexOf('[native code]') !== -1;
        var isWorking = false;
        var details = {};
        
        if (exists) {
            try {
                var sym = Symbol('test');
                isWorking = typeof sym === 'symbol';
                
                details.hasFor = typeof Symbol.for === 'function';
                details.hasKeyFor = typeof Symbol.keyFor === 'function';
                details.hasIterator = typeof Symbol.iterator !== 'undefined';
            } catch (e) {
                details.error = e.message;
            }
        }
        
        return { exists: exists, isNative: isNative, isWorking: isWorking, details: details };
    },
    
    // Detect Proxy support
    detectProxy: function() {
        var exists = typeof Proxy !== 'undefined';
        var isNative = exists && Proxy.toString().indexOf('[native code]') !== -1;
        var isWorking = false;
        var details = {};
        
        if (exists) {
            try {
                var target = {};
                var handler = {
                    get: function(obj, prop) {
                        return prop in obj ? obj[prop] : 'proxy';
                    }
                };
                
                var proxy = new Proxy(target, handler);
                isWorking = proxy.test === 'proxy';
                
                details.hasRevocable = typeof Proxy.revocable === 'function';
            } catch (e) {
                details.error = e.message;
            }
        }
        
        return { exists: exists, isNative: isNative, isWorking: isWorking, details: details };
    },
    
    // Detect IntersectionObserver support
    detectIntersectionObserver: function() {
        var exists = typeof IntersectionObserver !== 'undefined';
        var isNative = exists && IntersectionObserver.toString().indexOf('[native code]') !== -1;
        var isWorking = false;
        var details = {};
        
        if (exists) {
            try {
                var observer = new IntersectionObserver(function() {});
                isWorking = typeof observer.observe === 'function';
                observer.disconnect();
            } catch (e) {
                details.error = e.message;
            }
        }
        
        return { exists: exists, isNative: isNative, isWorking: isWorking, details: details };
    },
    
    // Detect Custom Elements support
    detectCustomElements: function() {
        var exists = typeof customElements !== 'undefined';
        var isNative = exists && customElements.define.toString().indexOf('[native code]') !== -1;
        var isWorking = false;
        var details = {};
        
        if (exists) {
            try {
                isWorking = typeof customElements.define === 'function';
                details.hasGet = typeof customElements.get === 'function';
                details.hasWhenDefined = typeof customElements.whenDefined === 'function';
            } catch (e) {
                details.error = e.message;
            }
        }
        
        return { exists: exists, isNative: isNative, isWorking: isWorking, details: details };
    },
    
    // Batch detection
    detectAll: function() {
        var features = [
            'Promise', 'fetch', 'Map', 'Set', 'Symbol', 'Proxy',
            'IntersectionObserver', 'CustomElements'
        ];
        
        var results = {};
        
        features.forEach(function(feature) {
            results[feature] = this.detectFeature(feature);
        }.bind(this));
        
        console.table(Object.keys(results).map(function(name) {
            var result = results[name];
            return {
                Feature: name,
                Exists: result.exists ? '✓' : '✗',
                Native: result.isNative ? '✓' : '✗',
                Working: result.isWorking ? '✓' : '✗'
            };
        }));
        
        return results;
    },
    
    // Debug why feature detection fails
    debugDetection: function(featureName, detectionCode) {
        console.group('Debugging Feature Detection: ' + featureName);
        
        try {
            var result = detectionCode();
            console.log('Detection Result:', result);
            console.log('Type:', typeof result);
            console.log('Truthy:', !!result);
        } catch (e) {
            console.error('Detection Error:', e);
            console.log('Stack:', e.stack);
        }
        
        console.groupEnd();
    }
};

// Global helper
window.detectFeature = FeatureDetector.detectFeature.bind(FeatureDetector);
window.detectAllFeatures = FeatureDetector.detectAll.bind(FeatureDetector);

// Usage:
// detectFeature('Promise');
// detectAllFeatures();
// FeatureDetector.debugDetection('CustomElements', function() {
//     return typeof customElements !== 'undefined';
// });

// conflict-resolver.js
var PolyfillConflictResolver = {
    conflicts: [],
    
    // Detect all conflicts
    detectConflicts: function() {
        this.conflicts = [];
        
        // Check for duplicate polyfills
        this.checkDuplicates();
        
        // Check for override conflicts
        this.checkOverrides();
        
        // Check for namespace collisions
        this.checkNamespaceCollisions();
        
        // Report conflicts
        this.reportConflicts();
        
        return this.conflicts;
    },
    
    // Check for duplicate polyfills
    checkDuplicates: function() {
        var methods = [
            { obj: Array.prototype, name: 'find', feature: 'Array.find' },
            { obj: Array.prototype, name: 'includes', feature: 'Array.includes' },
            { obj: Object, name: 'assign', feature: 'Object.assign' },
            { obj: String.prototype, name: 'includes', feature: 'String.includes' },
            { obj: window, name: 'Promise', feature: 'Promise' },
            { obj: window, name: 'fetch', feature: 'fetch' }
        ];
        
        methods.forEach(function(method) {
            var fn = method.obj[method.name];
            
            if (!fn) return;
            
            // Check if method has been polyfilled multiple times
            var descriptor = Object.getOwnPropertyDescriptor(method.obj, method.name);
            
            if (descriptor && descriptor.writable === false && descriptor.configurable === false) {
                // Check if there are multiple definitions
                var source = fn.toString();
                
                if (source.includes('polyfill') && source.length > 1000) {
                    this.conflicts.push({
                        type: 'duplicate',
                        feature: method.feature,
                        severity: 'warning',
                        message: 'Possible duplicate polyfill detected'
                    });
                }
            }
        }.bind(this));
    },
    
    // Check for override conflicts
    checkOverrides: function() {
        var methods = [
            { obj: Array.prototype, name: 'map' },
            { obj: Array.prototype, name: 'filter' },
            { obj: Array.prototype, name: 'reduce' },
            { obj: Object, name: 'keys' },
            { obj: Object, name: 'values' }
        ];
        
        methods.forEach(function(method) {
            var fn = method.obj[method.name];
            
            if (!fn) return;
            
            var source = fn.toString();
            var isNative = source.indexOf('[native code]') !== -1;
            
            // Check if a polyfill overrode a native method
            var descriptor = Object.getOwnPropertyDescriptor(method.obj, method.name);
            
            if (!isNative && descriptor && !descriptor.configurable) {
                this.conflicts.push({
                    type: 'override',
                    feature: method.obj.constructor.name + '.' + method.name,
                    severity: 'error',
                    message: 'Polyfill incorrectly overrides native method'
                });
            }
        }.bind(this));
    },
    
    // Check for namespace collisions
    checkNamespaceCollisions: function() {
        var globalVars = ['Promise', 'Map', 'Set', 'Symbol', 'Proxy', 'Reflect'];
        
        globalVars.forEach(function(varName) {
            var value = window[varName];
            
            if (!value) return;
            
            // Check if variable is defined multiple times
            var descriptor = Object.getOwnPropertyDescriptor(window, varName);
            
            if (descriptor && descriptor.configurable === false) {
                var source = value.toString();
                
                if (source.includes('polyfill')) {
                    this.conflicts.push({
                        type: 'namespace',
                        feature: varName,
                        severity: 'warning',
                        message: 'Global namespace collision detected'
                    });
                }
            }
        }.bind(this));
    },
    
    // Report all conflicts
    reportConflicts: function() {
        if (this.conflicts.length === 0) {
            console.log('✓ No polyfill conflicts detected');
            return;
        }
        
        console.group('⚠️  Polyfill Conflicts (' + this.conflicts.length + ')');
        
        this.conflicts.forEach(function(conflict, index) {
            var icon = conflict.severity === 'error' ? '❌' : '⚠️';
            
            console.group(icon + ' Conflict ' + (index + 1) + ': ' + conflict.type);
            console.log('Feature:', conflict.feature);
            console.log('Severity:', conflict.severity);
            console.log('Message:', conflict.message);
            console.groupEnd();
        });
        
        console.groupEnd();
    },
    
    // Resolve conflicts automatically
    resolveConflicts: function() {
        console.log('Attempting to resolve conflicts...');
        
        this.conflicts.forEach(function(conflict) {
            switch (conflict.type) {
                case 'duplicate':
                    this.resolveDuplicate(conflict);
                    break;
                case 'override':
                    this.resolveOverride(conflict);
                    break;
                case 'namespace':
                    this.resolveNamespace(conflict);
                    break;
            }
        }.bind(this));
        
        console.log('Conflict resolution complete');
    },
    
    // Resolve duplicate polyfills
    resolveDuplicate: function(conflict) {
        console.log('Resolving duplicate:', conflict.feature);
        
        // Remove duplicate script tags
        var scripts = document.querySelectorAll('script[src*="' + conflict.feature.toLowerCase() + '"]');
        
        if (scripts.length > 1) {
            for (var i = 1; i < scripts.length; i++) {
                console.log('Removing duplicate script:', scripts[i].src);
                scripts[i].remove();
            }
        }
    },
    
    // Resolve override conflicts
    resolveOverride: function(conflict) {
        console.error('Cannot auto-resolve override conflict:', conflict.feature);
        console.log('Manual intervention required:');
        console.log('1. Check if native implementation exists');
        console.log('2. Remove polyfill if native is available');
        console.log('3. Or guard polyfill with feature detection');
    },
    
    // Resolve namespace collisions
    resolveNamespace: function(conflict) {
        console.log('Resolving namespace collision:', conflict.feature);
        console.log('Consider using ES modules instead of global variables');
    },
    
    // Prevent future conflicts
    preventConflicts: function() {
        // Freeze native methods to prevent override
        var methods = [
            { obj: Array.prototype, names: ['map', 'filter', 'reduce', 'forEach'] },
            { obj: Object, names: ['keys', 'values', 'entries', 'assign'] }
        ];
        
        methods.forEach(function(group) {
            group.names.forEach(function(name) {
                if (group.obj[name]) {
                    var descriptor = Object.getOwnPropertyDescriptor(group.obj, name);
                    
                    if (descriptor && descriptor.configurable) {
                        Object.defineProperty(group.obj, name, {
                            value: group.obj[name],
                            writable: false,
                            configurable: false,
                            enumerable: false
                        });
                        
                        console.log('Protected:', group.obj.constructor.name + '.' + name);
                    }
                }
            });
        });
    }
};

// Global helper
window.checkPolyfillConflicts = function() {
    return PolyfillConflictResolver.detectConflicts();
};

window.resolvePolyfillConflicts = function() {
    PolyfillConflictResolver.resolveConflicts();
};

// Usage:
// checkPolyfillConflicts();
// resolvePolyfillConflicts();
// PolyfillConflictResolver.preventConflicts();