Performance Guide

This comprehensive guide covers performance optimization techniques, monitoring, and best practices for Trae development.

Introduction to Performance

Why Performance Matters

• User Experience: Faster applications provide better user satisfaction
• Productivity: Developers work more efficiently with responsive tools
• Resource Efficiency: Optimized code uses less CPU, memory, and battery
• Scalability: Well-performing code handles larger workloads
• Cost Reduction: Efficient applications require fewer resources

Performance Metrics

• Startup Time: Time to launch and become responsive
• Memory Usage: RAM consumption during operation
• CPU Usage: Processor utilization
• Response Time: Time to complete operations
• Throughput: Operations completed per unit time
• Battery Usage: Power consumption (mobile/laptop)

Performance Monitoring

Built-in Performance Tools

Performance Monitor

// Enable performance monitoring
import * as trae from '@trae/extension-api';

class PerformanceMonitor {
    private metrics: Map<string, PerformanceMetric[]> = new Map();
    
    startMeasurement(name: string): PerformanceMeasurement {
        const start = performance.now();
        return {
            name,
            start,
            end: () => {
                const end = performance.now();
                const duration = end - start;
                this.recordMetric(name, duration);
                return duration;
            }
        };
    }
    
    recordMetric(name: string, duration: number): void {
        if (!this.metrics.has(name)) {
            this.metrics.set(name, []);
        }
        
        const metric: PerformanceMetric = {
            timestamp: Date.now(),
            duration,
            memory: process.memoryUsage().heapUsed
        };
        
        this.metrics.get(name)!.push(metric);
    }
    
    getAverageTime(name: string): number {
        const metrics = this.metrics.get(name) || [];
        if (metrics.length === 0) return 0;
        
        const total = metrics.reduce((sum, metric) => sum + metric.duration, 0);
        return total / metrics.length;
    }
    
    getReport(): PerformanceReport {
        const report: PerformanceReport = {
            timestamp: Date.now(),
            metrics: new Map()
        };
        
        for (const [name, metrics] of this.metrics) {
            const avgDuration = this.getAverageTime(name);
            const maxDuration = Math.max(...metrics.map(m => m.duration));
            const minDuration = Math.min(...metrics.map(m => m.duration));
            
            report.metrics.set(name, {
                count: metrics.length,
                average: avgDuration,
                min: minDuration,
                max: maxDuration
            });
        }
        
        return report;
    }
}

interface PerformanceMeasurement {
    name: string;
    start: number;
    end(): number;
}

interface PerformanceMetric {
    timestamp: number;
    duration: number;
    memory: number;
}

interface PerformanceReport {
    timestamp: number;
    metrics: Map<string, {
        count: number;
        average: number;
        min: number;
        max: number;
    }>;
}

Memory Profiler

class MemoryProfiler {
    private snapshots: MemorySnapshot[] = [];
    
    takeSnapshot(label: string): MemorySnapshot {
        const usage = process.memoryUsage();
        const snapshot: MemorySnapshot = {
            label,
            timestamp: Date.now(),
            heapUsed: usage.heapUsed,
            heapTotal: usage.heapTotal,
            external: usage.external,
            rss: usage.rss
        };
        
        this.snapshots.push(snapshot);
        return snapshot;
    }
    
    compareSnapshots(label1: string, label2: string): MemoryComparison {
        const snapshot1 = this.snapshots.find(s => s.label === label1);
        const snapshot2 = this.snapshots.find(s => s.label === label2);
        
        if (!snapshot1 || !snapshot2) {
            throw new Error('Snapshot not found');
        }
        
        return {
            heapUsedDiff: snapshot2.heapUsed - snapshot1.heapUsed,
            heapTotalDiff: snapshot2.heapTotal - snapshot1.heapTotal,
            externalDiff: snapshot2.external - snapshot1.external,
            rssDiff: snapshot2.rss - snapshot1.rss
        };
    }
    
    detectMemoryLeaks(): MemoryLeak[] {
        const leaks: MemoryLeak[] = [];
        
        for (let i = 1; i < this.snapshots.length; i++) {
            const prev = this.snapshots[i - 1];
            const curr = this.snapshots[i];
            
            const heapGrowth = curr.heapUsed - prev.heapUsed;
            const timeElapsed = curr.timestamp - prev.timestamp;
            
            // Detect significant memory growth
            if (heapGrowth > 10 * 1024 * 1024 && timeElapsed < 60000) { // 10MB in 1 minute
                leaks.push({
                    startSnapshot: prev.label,
                    endSnapshot: curr.label,
                    memoryGrowth: heapGrowth,
                    timeElapsed
                });
            }
        }
        
        return leaks;
    }
}

interface MemorySnapshot {
    label: string;
    timestamp: number;
    heapUsed: number;
    heapTotal: number;
    external: number;
    rss: number;
}

interface MemoryComparison {
    heapUsedDiff: number;
    heapTotalDiff: number;
    externalDiff: number;
    rssDiff: number;
}

interface MemoryLeak {
    startSnapshot: string;
    endSnapshot: string;
    memoryGrowth: number;
    timeElapsed: number;
}

CPU Profiling

class CPUProfiler {
    private profiles: Map<string, CPUProfile> = new Map();
    
    startProfiling(name: string): void {
        const profile: CPUProfile = {
            name,
            startTime: process.hrtime.bigint(),
            samples: [],
            isRunning: true
        };
        
        this.profiles.set(name, profile);
        
        // Sample CPU usage periodically
        const interval = setInterval(() => {
            if (!profile.isRunning) {
                clearInterval(interval);
                return;
            }
            
            const usage = process.cpuUsage();
            profile.samples.push({
                timestamp: process.hrtime.bigint(),
                user: usage.user,
                system: usage.system
            });
        }, 100); // Sample every 100ms
    }
    
    stopProfiling(name: string): CPUProfile | undefined {
        const profile = this.profiles.get(name);
        if (!profile) return undefined;
        
        profile.isRunning = false;
        profile.endTime = process.hrtime.bigint();
        
        return profile;
    }
    
    analyzeCPUUsage(name: string): CPUAnalysis | undefined {
        const profile = this.profiles.get(name);
        if (!profile || profile.samples.length === 0) return undefined;
        
        const totalDuration = Number(profile.endTime! - profile.startTime) / 1e6; // Convert to ms
        const avgUserTime = profile.samples.reduce((sum, s) => sum + s.user, 0) / profile.samples.length;
        const avgSystemTime = profile.samples.reduce((sum, s) => sum + s.system, 0) / profile.samples.length;
        
        return {
            name,
            totalDuration,
            averageUserTime: avgUserTime,
            averageSystemTime: avgSystemTime,
            sampleCount: profile.samples.length,
            cpuUtilization: ((avgUserTime + avgSystemTime) / totalDuration) * 100
        };
    }
}

interface CPUProfile {
    name: string;
    startTime: bigint;
    endTime?: bigint;
    samples: CPUSample[];
    isRunning: boolean;
}

interface CPUSample {
    timestamp: bigint;
    user: number;
    system: number;
}

interface CPUAnalysis {
    name: string;
    totalDuration: number;
    averageUserTime: number;
    averageSystemTime: number;
    sampleCount: number;
    cpuUtilization: number;
}

Performance Optimization Techniques

1. Code Optimization

Efficient Algorithms

// Inefficient: O(n²) complexity
function findDuplicatesInefficient(arr: number[]): number[] {
    const duplicates: number[] = [];
    
    for (let i = 0; i < arr.length; i++) {
        for (let j = i + 1; j < arr.length; j++) {
            if (arr[i] === arr[j] && !duplicates.includes(arr[i])) {
                duplicates.push(arr[i]);
            }
        }
    }
    
    return duplicates;
}

// Efficient: O(n) complexity
function findDuplicatesEfficient(arr: number[]): number[] {
    const seen = new Set<number>();
    const duplicates = new Set<number>();
    
    for (const num of arr) {
        if (seen.has(num)) {
            duplicates.add(num);
        } else {
            seen.add(num);
        }
    }
    
    return Array.from(duplicates);
}

Lazy Loading

class LazyLoader<T> {
    private _value: T | undefined;
    private _factory: () => T;
    private _isLoaded = false;
    
    constructor(factory: () => T) {
        this._factory = factory;
    }
    
    get value(): T {
        if (!this._isLoaded) {
            this._value = this._factory();
            this._isLoaded = true;
        }
        return this._value!;
    }
    
    get isLoaded(): boolean {
        return this._isLoaded;
    }
    
    reset(): void {
        this._value = undefined;
        this._isLoaded = false;
    }
}

// Usage
class ExpensiveResource {
    private lazyData = new LazyLoader(() => this.loadExpensiveData());
    
    get data(): ComplexData {
        return this.lazyData.value;
    }
    
    private loadExpensiveData(): ComplexData {
        // Expensive operation
        console.log('Loading expensive data...');
        return new ComplexData();
    }
}

Memoization

class MemoizedCalculator {
    private cache = new Map<string, number>();
    
    fibonacci(n: number): number {
        const key = `fib_${n}`;
        
        if (this.cache.has(key)) {
            return this.cache.get(key)!;
        }
        
        let result: number;
        if (n <= 1) {
            result = n;
        } else {
            result = this.fibonacci(n - 1) + this.fibonacci(n - 2);
        }
        
        this.cache.set(key, result);
        return result;
    }
    
    clearCache(): void {
        this.cache.clear();
    }
    
    getCacheSize(): number {
        return this.cache.size;
    }
}

// Generic memoization decorator
function memoize<T extends (...args: any[]) => any>(fn: T): T {
    const cache = new Map<string, ReturnType<T>>();
    
    return ((...args: Parameters<T>): ReturnType<T> => {
        const key = JSON.stringify(args);
        
        if (cache.has(key)) {
            return cache.get(key)!;
        }
        
        const result = fn(...args);
        cache.set(key, result);
        return result;
    }) as T;
}

// Usage
const memoizedExpensiveFunction = memoize((x: number, y: number) => {
    // Expensive calculation
    return Math.pow(x, y);
});

2. Memory Optimization

Object Pooling

class ObjectPool<T> {
    private pool: T[] = [];
    private factory: () => T;
    private reset: (obj: T) => void;
    
    constructor(factory: () => T, reset: (obj: T) => void, initialSize = 10) {
        this.factory = factory;
        this.reset = reset;
        
        // Pre-populate pool
        for (let i = 0; i < initialSize; i++) {
            this.pool.push(factory());
        }
    }
    
    acquire(): T {
        if (this.pool.length > 0) {
            return this.pool.pop()!;
        }
        
        // Pool is empty, create new object
        return this.factory();
    }
    
    release(obj: T): void {
        this.reset(obj);
        this.pool.push(obj);
    }
    
    get size(): number {
        return this.pool.length;
    }
}

// Usage example
class ExpensiveObject {
    data: number[] = [];
    
    reset(): void {
        this.data.length = 0;
    }
}

const objectPool = new ObjectPool(
    () => new ExpensiveObject(),
    (obj) => obj.reset(),
    5
);

// Use pooled objects
function processData(input: number[]): number {
    const obj = objectPool.acquire();
    
    try {
        obj.data = input.slice(); // Copy data
        // Process data...
        return obj.data.reduce((sum, val) => sum + val, 0);
    } finally {
        objectPool.release(obj);
    }
}

Weak References

class CacheWithWeakRefs<K extends object, V> {
    private cache = new WeakMap<K, V>();
    
    set(key: K, value: V): void {
        this.cache.set(key, value);
    }
    
    get(key: K): V | undefined {
        return this.cache.get(key);
    }
    
    has(key: K): boolean {
        return this.cache.has(key);
    }
    
    delete(key: K): boolean {
        return this.cache.delete(key);
    }
}

// Usage: Cache will automatically clean up when objects are garbage collected
const documentCache = new CacheWithWeakRefs<Document, ProcessedData>();

function processDocument(doc: Document): ProcessedData {
    if (documentCache.has(doc)) {
        return documentCache.get(doc)!;
    }
    
    const processed = expensiveProcessing(doc);
    documentCache.set(doc, processed);
    return processed;
}

3. Asynchronous Optimization

Debouncing and Throttling

class PerformanceUtils {
    static debounce<T extends (...args: any[]) => any>(
        func: T,
        delay: number
    ): (...args: Parameters<T>) => void {
        let timeoutId: NodeJS.Timeout;
        
        return (...args: Parameters<T>) => {
            clearTimeout(timeoutId);
            timeoutId = setTimeout(() => func(...args), delay);
        };
    }
    
    static throttle<T extends (...args: any[]) => any>(
        func: T,
        limit: number
    ): (...args: Parameters<T>) => void {
        let inThrottle: boolean;
        
        return (...args: Parameters<T>) => {
            if (!inThrottle) {
                func(...args);
                inThrottle = true;
                setTimeout(() => inThrottle = false, limit);
            }
        };
    }
}

// Usage
class SearchHandler {
    private debouncedSearch = PerformanceUtils.debounce(
        (query: string) => this.performSearch(query),
        300
    );
    
    private throttledScroll = PerformanceUtils.throttle(
        () => this.handleScroll(),
        100
    );
    
    onSearchInput(query: string): void {
        this.debouncedSearch(query);
    }
    
    onScroll(): void {
        this.throttledScroll();
    }
    
    private performSearch(query: string): void {
        // Expensive search operation
    }
    
    private handleScroll(): void {
        // Handle scroll events
    }
}

Batch Processing

class BatchProcessor<T> {
    private queue: T[] = [];
    private batchSize: number;
    private flushInterval: number;
    private processor: (items: T[]) => Promise<void>;
    private timer: NodeJS.Timeout | null = null;
    
    constructor(
        processor: (items: T[]) => Promise<void>,
        batchSize = 100,
        flushInterval = 1000
    ) {
        this.processor = processor;
        this.batchSize = batchSize;
        this.flushInterval = flushInterval;
    }
    
    add(item: T): void {
        this.queue.push(item);
        
        if (this.queue.length >= this.batchSize) {
            this.flush();
        } else if (!this.timer) {
            this.timer = setTimeout(() => this.flush(), this.flushInterval);
        }
    }
    
    async flush(): Promise<void> {
        if (this.timer) {
            clearTimeout(this.timer);
            this.timer = null;
        }
        
        if (this.queue.length === 0) return;
        
        const batch = this.queue.splice(0, this.batchSize);
        await this.processor(batch);
    }
    
    get queueSize(): number {
        return this.queue.length;
    }
}

// Usage
const logProcessor = new BatchProcessor(
    async (logs: LogEntry[]) => {
        // Process batch of logs
        await sendLogsToServer(logs);
    },
    50,  // Batch size
    2000 // Flush interval (2 seconds)
);

// Add logs individually
logProcessor.add({ level: 'info', message: 'User logged in' });
logProcessor.add({ level: 'error', message: 'Database connection failed' });

4. UI Performance

Virtual Scrolling

class VirtualScrollList {
    private container: HTMLElement;
    private itemHeight: number;
    private visibleCount: number;
    private totalItems: number;
    private scrollTop = 0;
    private items: any[];
    
    constructor(
        container: HTMLElement,
        items: any[],
        itemHeight: number
    ) {
        this.container = container;
        this.items = items;
        this.itemHeight = itemHeight;
        this.totalItems = items.length;
        this.visibleCount = Math.ceil(container.clientHeight / itemHeight) + 2;
        
        this.setupScrolling();
        this.render();
    }
    
    private setupScrolling(): void {
        this.container.addEventListener('scroll', () => {
            this.scrollTop = this.container.scrollTop;
            this.render();
        });
    }
    
    private render(): void {
        const startIndex = Math.floor(this.scrollTop / this.itemHeight);
        const endIndex = Math.min(startIndex + this.visibleCount, this.totalItems);
        
        // Clear container
        this.container.innerHTML = '';
        
        // Create spacer for items above viewport
        const topSpacer = document.createElement('div');
        topSpacer.style.height = `${startIndex * this.itemHeight}px`;
        this.container.appendChild(topSpacer);
        
        // Render visible items
        for (let i = startIndex; i < endIndex; i++) {
            const itemElement = this.createItemElement(this.items[i], i);
            this.container.appendChild(itemElement);
        }
        
        // Create spacer for items below viewport
        const bottomSpacer = document.createElement('div');
        const remainingHeight = (this.totalItems - endIndex) * this.itemHeight;
        bottomSpacer.style.height = `${remainingHeight}px`;
        this.container.appendChild(bottomSpacer);
    }
    
    private createItemElement(item: any, index: number): HTMLElement {
        const element = document.createElement('div');
        element.style.height = `${this.itemHeight}px`;
        element.textContent = `Item ${index}: ${item.name}`;
        return element;
    }
    
    updateItems(newItems: any[]): void {
        this.items = newItems;
        this.totalItems = newItems.length;
        this.render();
    }
}

Efficient DOM Updates

class DOMBatcher {
    private readOperations: (() => void)[] = [];
    private writeOperations: (() => void)[] = [];
    private isScheduled = false;
    
    read(operation: () => void): void {
        this.readOperations.push(operation);
        this.schedule();
    }
    
    write(operation: () => void): void {
        this.writeOperations.push(operation);
        this.schedule();
    }
    
    private schedule(): void {
        if (this.isScheduled) return;
        
        this.isScheduled = true;
        requestAnimationFrame(() => {
            // Execute all read operations first
            while (this.readOperations.length > 0) {
                const operation = this.readOperations.shift()!;
                operation();
            }
            
            // Then execute all write operations
            while (this.writeOperations.length > 0) {
                const operation = this.writeOperations.shift()!;
                operation();
            }
            
            this.isScheduled = false;
        });
    }
}

// Usage
const domBatcher = new DOMBatcher();

function updateElements(elements: HTMLElement[]): void {
    const measurements: number[] = [];
    
    // Batch all read operations
    elements.forEach((element, index) => {
        domBatcher.read(() => {
            measurements[index] = element.offsetWidth;
        });
    });
    
    // Batch all write operations
    elements.forEach((element, index) => {
        domBatcher.write(() => {
            element.style.width = `${measurements[index] * 1.1}px`;
        });
    });
}

Extension Performance

Activation Optimization

// Lazy activation
export function activate(context: trae.ExtensionContext) {
    // Register lightweight commands immediately
    context.subscriptions.push(
        trae.commands.registerCommand('myExtension.quickAction', () => {
            // Lightweight operation
            trae.window.showInformationMessage('Quick action executed');
        })
    );
    
    // Defer heavy initialization
    let heavyFeatures: HeavyFeatures | undefined;
    
    context.subscriptions.push(
        trae.commands.registerCommand('myExtension.heavyAction', async () => {
            if (!heavyFeatures) {
                heavyFeatures = await initializeHeavyFeatures();
            }
            heavyFeatures.performAction();
        })
    );
}

async function initializeHeavyFeatures(): Promise<HeavyFeatures> {
    // Load heavy dependencies only when needed
    const heavyModule = await import('./heavy-module');
    return new heavyModule.HeavyFeatures();
}

Event Handler Optimization

class OptimizedEventHandler {
    private disposables: trae.Disposable[] = [];
    
    constructor(context: trae.ExtensionContext) {
        this.setupOptimizedHandlers(context);
    }
    
    private setupOptimizedHandlers(context: trae.ExtensionContext): void {
        // Debounced document change handler
        const debouncedHandler = PerformanceUtils.debounce(
            (document: trae.TextDocument) => this.handleDocumentChange(document),
            500
        );
        
        this.disposables.push(
            trae.workspace.onDidChangeTextDocument((event) => {
                // Only handle specific file types
                if (this.shouldHandleDocument(event.document)) {
                    debouncedHandler(event.document);
                }
            })
        );
        
        // Throttled selection change handler
        const throttledSelectionHandler = PerformanceUtils.throttle(
            (event: trae.TextEditorSelectionChangeEvent) => {
                this.handleSelectionChange(event);
            },
            100
        );
        
        this.disposables.push(
            trae.window.onDidChangeTextEditorSelection(throttledSelectionHandler)
        );
        
        context.subscriptions.push(...this.disposables);
    }
    
    private shouldHandleDocument(document: trae.TextDocument): boolean {
        // Filter documents to reduce unnecessary processing
        const supportedLanguages = ['typescript', 'javascript', 'python'];
        return supportedLanguages.includes(document.languageId) &&
               !document.uri.scheme.startsWith('git');
    }
    
    private handleDocumentChange(document: trae.TextDocument): void {
        // Optimized document processing
    }
    
    private handleSelectionChange(event: trae.TextEditorSelectionChangeEvent): void {
        // Optimized selection processing
    }
}

Performance Testing

Benchmark Suite

class BenchmarkSuite {
    private results: BenchmarkResult[] = [];
    
    async runBenchmark(
        name: string,
        fn: () => Promise<void> | void,
        iterations = 1000
    ): Promise<BenchmarkResult> {
        const times: number[] = [];
        const memoryBefore = process.memoryUsage().heapUsed;
        
        // Warm up
        for (let i = 0; i < 10; i++) {
            await fn();
        }
        
        // Run benchmark
        for (let i = 0; i < iterations; i++) {
            const start = performance.now();
            await fn();
            const end = performance.now();
            times.push(end - start);
        }
        
        const memoryAfter = process.memoryUsage().heapUsed;
        
        const result: BenchmarkResult = {
            name,
            iterations,
            totalTime: times.reduce((sum, time) => sum + time, 0),
            averageTime: times.reduce((sum, time) => sum + time, 0) / times.length,
            minTime: Math.min(...times),
            maxTime: Math.max(...times),
            memoryUsed: memoryAfter - memoryBefore,
            operationsPerSecond: 1000 / (times.reduce((sum, time) => sum + time, 0) / times.length)
        };
        
        this.results.push(result);
        return result;
    }
    
    compare(name1: string, name2: string): BenchmarkComparison | null {
        const result1 = this.results.find(r => r.name === name1);
        const result2 = this.results.find(r => r.name === name2);
        
        if (!result1 || !result2) return null;
        
        return {
            name1,
            name2,
            speedImprovement: result1.averageTime / result2.averageTime,
            memoryImprovement: result1.memoryUsed / result2.memoryUsed,
            winner: result1.averageTime < result2.averageTime ? name1 : name2
        };
    }
    
    generateReport(): string {
        let report = 'Benchmark Results\n';
        report += '=================\n\n';
        
        for (const result of this.results) {
            report += `${result.name}:\n`;
            report += `  Average Time: ${result.averageTime.toFixed(2)}ms\n`;
            report += `  Min Time: ${result.minTime.toFixed(2)}ms\n`;
            report += `  Max Time: ${result.maxTime.toFixed(2)}ms\n`;
            report += `  Operations/sec: ${result.operationsPerSecond.toFixed(0)}\n`;
            report += `  Memory Used: ${(result.memoryUsed / 1024 / 1024).toFixed(2)}MB\n\n`;
        }
        
        return report;
    }
}

interface BenchmarkResult {
    name: string;
    iterations: number;
    totalTime: number;
    averageTime: number;
    minTime: number;
    maxTime: number;
    memoryUsed: number;
    operationsPerSecond: number;
}

interface BenchmarkComparison {
    name1: string;
    name2: string;
    speedImprovement: number;
    memoryImprovement: number;
    winner: string;
}

// Usage
const benchmark = new BenchmarkSuite();

async function runPerformanceTests(): Promise<void> {
    await benchmark.runBenchmark('Array.forEach', () => {
        const arr = Array.from({ length: 1000 }, (_, i) => i);
        arr.forEach(x => x * 2);
    });
    
    await benchmark.runBenchmark('for loop', () => {
        const arr = Array.from({ length: 1000 }, (_, i) => i);
        for (let i = 0; i < arr.length; i++) {
            arr[i] * 2;
        }
    });
    
    const comparison = benchmark.compare('Array.forEach', 'for loop');
    console.log('Comparison:', comparison);
    console.log(benchmark.generateReport());
}

Performance Best Practices

1. General Guidelines

• Measure First: Always profile before optimizing
• Optimize Bottlenecks: Focus on the slowest parts
• Avoid Premature Optimization: Don't optimize until necessary
• Use Appropriate Data Structures: Choose the right tool for the job
• Minimize Allocations: Reuse objects when possible

2. Memory Management

// Good: Reuse objects
class ObjectReuser {
    private tempArray: number[] = [];
    
    processData(input: number[]): number {
        // Reuse array instead of creating new one
        this.tempArray.length = 0;
        this.tempArray.push(...input.filter(x => x > 0));
        return this.tempArray.reduce((sum, x) => sum + x, 0);
    }
}

// Bad: Create new objects frequently
class ObjectCreator {
    processData(input: number[]): number {
        const filtered = input.filter(x => x > 0); // New array
        return filtered.reduce((sum, x) => sum + x, 0);
    }
}

3. Async Operations

// Good: Parallel processing
async function processFilesParallel(files: string[]): Promise<ProcessedFile[]> {
    const promises = files.map(file => processFile(file));
    return Promise.all(promises);
}

// Bad: Sequential processing
async function processFilesSequential(files: string[]): Promise<ProcessedFile[]> {
    const results: ProcessedFile[] = [];
    for (const file of files) {
        const result = await processFile(file);
        results.push(result);
    }
    return results;
}

4. Event Handling

// Good: Efficient event handling
class EfficientEventHandler {
    private handleClick = (event: MouseEvent) => {
        // Use event delegation
        const target = event.target as HTMLElement;
        if (target.matches('.button')) {
            this.handleButtonClick(target);
        }
    };
    
    constructor() {
        // Single event listener for all buttons
        document.addEventListener('click', this.handleClick);
    }
    
    private handleButtonClick(button: HTMLElement): void {
        // Handle button click
    }
}

// Bad: Multiple event listeners
class InefficientEventHandler {
    constructor() {
        // Separate listener for each button
        const buttons = document.querySelectorAll('.button');
        buttons.forEach(button => {
            button.addEventListener('click', () => {
                this.handleButtonClick(button as HTMLElement);
            });
        });
    }
    
    private handleButtonClick(button: HTMLElement): void {
        // Handle button click
    }
}

Performance Monitoring Dashboard

class PerformanceDashboard {
    private monitor: PerformanceMonitor;
    private memoryProfiler: MemoryProfiler;
    private cpuProfiler: CPUProfiler;
    
    constructor() {
        this.monitor = new PerformanceMonitor();
        this.memoryProfiler = new MemoryProfiler();
        this.cpuProfiler = new CPUProfiler();
    }
    
    startMonitoring(): void {
        // Start periodic monitoring
        setInterval(() => {
            this.collectMetrics();
        }, 5000); // Every 5 seconds
    }
    
    private collectMetrics(): void {
        // Collect memory snapshot
        this.memoryProfiler.takeSnapshot(`snapshot_${Date.now()}`);
        
        // Check for memory leaks
        const leaks = this.memoryProfiler.detectMemoryLeaks();
        if (leaks.length > 0) {
            console.warn('Memory leaks detected:', leaks);
        }
        
        // Generate performance report
        const report = this.monitor.getReport();
        this.updateDashboard(report);
    }
    
    private updateDashboard(report: PerformanceReport): void {
        // Update UI dashboard with performance metrics
        const dashboardData = {
            timestamp: report.timestamp,
            metrics: Array.from(report.metrics.entries()).map(([name, stats]) => ({
                name,
                ...stats
            }))
        };
        
        // Send to dashboard UI
        this.sendToDashboard(dashboardData);
    }
    
    private sendToDashboard(data: any): void {
        // Implementation to send data to dashboard
        console.log('Dashboard update:', data);
    }
    
    generatePerformanceReport(): PerformanceReport {
        return this.monitor.getReport();
    }
    
    exportMetrics(): string {
        const report = this.generatePerformanceReport();
        return JSON.stringify(report, null, 2);
    }
}

Troubleshooting Performance Issues

Common Performance Problems

1. Memory Leaks

   • Symptoms: Increasing memory usage over time
   • Solutions: Proper cleanup, weak references, object pooling

2. CPU Intensive Operations

   • Symptoms: High CPU usage, UI freezing
   • Solutions: Web Workers, async processing, optimization

3. Inefficient Algorithms

   • Symptoms: Slow response times
   • Solutions: Algorithm optimization, better data structures

4. Excessive DOM Manipulation

   • Symptoms: Slow UI updates
   • Solutions: Batch updates, virtual scrolling, efficient selectors

Debugging Tools

• Chrome DevTools: Profiling and debugging
• Node.js Profiler: Server-side performance analysis
• Memory Analyzers: Heap dump analysis
• Performance APIs: Built-in browser performance measurement

Resources

Documentation

• Performance API Reference

Tools

• Performance Monitor Extension
• Memory Profiler
• Benchmark Suite

Related Guides

• Extension Development
• Refactoring Guide
• API Reference