Claude Code 性能优化指南

性能优化策略概览

算法与数据结构优化

时间复杂度优化

// 查找数组中的重复元素
function findDuplicates(arr) {
    const duplicates = [];
    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;
}

// 使用Set优化查找
function findDuplicates(arr) {
    const seen = new Set();
    const duplicates = new Set();
    
    for (const item of arr) {
        if (seen.has(item)) {
            duplicates.add(item);
        } else {
            seen.add(item);
        }
    }
    
    return Array.from(duplicates);
}

内存优化技巧

// 大数据处理的内存优化
class DataProcessor {
    // 使用生成器避免一次性加载大量数据
    *processLargeDataset(filePath) {
        const stream = fs.createReadStream(filePath, { encoding: 'utf8' });
        let buffer = '';
        
        for await (const chunk of stream) {
            buffer += chunk;
            const lines = buffer.split('\n');
            buffer = lines.pop(); // 保留不完整的行
            
            for (const line of lines) {
                if (line.trim()) {
                    yield this.processLine(line);
                }
            }
        }
        
        // 处理最后一行
        if (buffer.trim()) {
            yield this.processLine(buffer);
        }
    }
    
    // 批量处理减少内存占用
    async processBatch(items, batchSize = 1000) {
        const results = [];
        
        for (let i = 0; i < items.length; i += batchSize) {
            const batch = items.slice(i, i + batchSize);
            const batchResults = await Promise.all(
                batch.map(item => this.processItem(item))
            );
            results.push(...batchResults);
            
            // 强制垃圾回收（在Node.js中）
            if (global.gc && i % (batchSize * 10) === 0) {
                global.gc();
            }
        }
        
        return results;
    }
}

数据库性能优化

查询优化

// 数据库查询优化示例
class UserService {
    // 使用索引和限制查询字段
    async getUsers(filters, pagination) {
        const { page = 1, limit = 20 } = pagination;
        const offset = (page - 1) * limit;
        
        // 只查询需要的字段
        const query = `
            SELECT id, name, email, created_at
            FROM users 
            WHERE status = ? 
            AND created_at >= ?
            ORDER BY created_at DESC
            LIMIT ? OFFSET ?
        `;
        
        return await db.query(query, [
            filters.status,
            filters.startDate,
            limit,
            offset
        ]);
    }
    
    // 批量操作优化
    async createUsers(users) {
        // 使用批量插入而不是逐个插入
        const values = users.map(user => [
            user.name,
            user.email,
            user.password,
            new Date()
        ]);
        
        const query = `
            INSERT INTO users (name, email, password, created_at)
            VALUES ?
        `;
        
        return await db.query(query, [values]);
    }
    
    // 连接查询优化
    async getUsersWithProfiles() {
        // 使用JOIN而不是N+1查询
        const query = `
            SELECT 
                u.id, u.name, u.email,
                p.bio, p.avatar, p.location
            FROM users u
            LEFT JOIN profiles p ON u.id = p.user_id
            WHERE u.status = 'active'
        `;
        
        return await db.query(query);
    }
}

缓存策略

// 多层缓存策略
class CacheManager {
    constructor() {
        this.memoryCache = new Map();
        this.redisClient = redis.createClient();
    }
    
    async get(key) {
        // L1: 内存缓存
        if (this.memoryCache.has(key)) {
            return this.memoryCache.get(key);
        }
        
        // L2: Redis缓存
        const redisValue = await this.redisClient.get(key);
        if (redisValue) {
            const parsed = JSON.parse(redisValue);
            // 回填内存缓存
            this.memoryCache.set(key, parsed);
            return parsed;
        }
        
        return null;
    }
    
    async set(key, value, ttl = 3600) {
        // 同时设置两层缓存
        this.memoryCache.set(key, value);
        await this.redisClient.setex(key, ttl, JSON.stringify(value));
    }
    
    // 缓存预热
    async warmupCache(keys) {
        const pipeline = this.redisClient.pipeline();
        
        for (const key of keys) {
            pipeline.get(key);
        }
        
        const results = await pipeline.exec();
        
        results.forEach(([err, value], index) => {
            if (!err && value) {
                const key = keys[index];
                this.memoryCache.set(key, JSON.parse(value));
            }
        });
    }
}

前端性能优化

代码分割与懒加载

// React代码分割示例
import { lazy, Suspense } from 'react';

// 懒加载组件
const Dashboard = lazy(() => import('./Dashboard'));
const UserProfile = lazy(() => import('./UserProfile'));
const Analytics = lazy(() => import('./Analytics'));

function App() {
    return (
        
            }>
                
                    } />
                    } />
                    } />
                
            
        
    );
}

// 预加载关键路由
const preloadRoutes = () => {
    import('./Dashboard');
    import('./UserProfile');
};

// 在用户交互时预加载
document.addEventListener('mouseover', (e) => {
    if (e.target.matches('a[href="/dashboard"]')) {
        import('./Dashboard');
    }
});

虚拟滚动优化

// 虚拟滚动实现
class VirtualList {
    constructor(container, items, itemHeight) {
        this.container = container;
        this.items = items;
        this.itemHeight = itemHeight;
        this.visibleCount = Math.ceil(container.clientHeight / itemHeight) + 2;
        this.startIndex = 0;
        
        this.render();
        this.bindEvents();
    }
    
    render() {
        const endIndex = Math.min(
            this.startIndex + this.visibleCount,
            this.items.length
        );
        
        const visibleItems = this.items.slice(this.startIndex, endIndex);
        const offsetY = this.startIndex * this.itemHeight;
        
        this.container.innerHTML = `
            

                

                    ${visibleItems.map(item => `
                        

                            ${this.renderItem(item)}
                        
                    `).join('')}
                
            
        `;
    }
    
    bindEvents() {
        this.container.addEventListener('scroll', () => {
            const newStartIndex = Math.floor(
                this.container.scrollTop / this.itemHeight
            );
            
            if (newStartIndex !== this.startIndex) {
                this.startIndex = newStartIndex;
                this.render();
            }
        });
    }
}

网络性能优化

请求优化

// 请求合并和缓存
class APIClient {
    constructor() {
        this.requestCache = new Map();
        this.pendingRequests = new Map();
    }
    
    async get(url, options = {}) {
        const cacheKey = `${url}${JSON.stringify(options)}`;
        
        // 检查缓存
        if (this.requestCache.has(cacheKey)) {
            const cached = this.requestCache.get(cacheKey);
            if (Date.now() - cached.timestamp < 60000) { // 1分钟缓存
                return cached.data;
            }
        }
        
        // 检查是否有相同的请求正在进行
        if (this.pendingRequests.has(cacheKey)) {
            return this.pendingRequests.get(cacheKey);
        }
        
        // 发起新请求
        const promise = fetch(url, options)
            .then(response => response.json())
            .then(data => {
                // 缓存结果
                this.requestCache.set(cacheKey, {
                    data,
                    timestamp: Date.now()
                });
                
                // 清除pending状态
                this.pendingRequests.delete(cacheKey);
                
                return data;
            })
            .catch(error => {
                this.pendingRequests.delete(cacheKey);
                throw error;
            });
        
        this.pendingRequests.set(cacheKey, promise);
        return promise;
    }
    
    // 批量请求
    async batchGet(urls) {
        const requests = urls.map(url => this.get(url));
        return Promise.all(requests);
    }
}

资源压缩与CDN

// Webpack优化配置
module.exports = {
    optimization: {
        splitChunks: {
            chunks: 'all',
            cacheGroups: {
                vendor: {
                    test: /[\\/]node_modules[\\/]/,
                    name: 'vendors',
                    chunks: 'all',
                },
                common: {
                    name: 'common',
                    minChunks: 2,
                    chunks: 'all',
                    enforce: true
                }
            }
        },
        minimizer: [
            new TerserPlugin({
                terserOptions: {
                    compress: {
                        drop_console: true,
                        drop_debugger: true
                    }
                }
            }),
            new CssMinimizerPlugin()
        ]
    },
    plugins: [
        new CompressionPlugin({
            algorithm: 'gzip',
            test: /\.(js|css|html|svg)$/,
            threshold: 8192,
            minRatio: 0.8
        })
    ]
};

性能监控与分析

性能指标收集

// 性能监控工具
class PerformanceMonitor {
    constructor() {
        this.metrics = new Map();
        this.observers = [];
    }
    
    // 监控API响应时间
    measureAPICall(name, fn) {
        return async (...args) => {
            const start = performance.now();
            
            try {
                const result = await fn(...args);
                const duration = performance.now() - start;
                
                this.recordMetric(`api.${name}`, {
                    duration,
                    status: 'success',
                    timestamp: Date.now()
                });
                
                return result;
            } catch (error) {
                const duration = performance.now() - start;
                
                this.recordMetric(`api.${name}`, {
                    duration,
                    status: 'error',
                    error: error.message,
                    timestamp: Date.now()
                });
                
                throw error;
            }
        };
    }
    
    // 监控页面性能
    measurePageLoad() {
        if (typeof window !== 'undefined') {
            window.addEventListener('load', () => {
                const navigation = performance.getEntriesByType('navigation')[0];
                
                this.recordMetric('page.load', {
                    domContentLoaded: navigation.domContentLoadedEventEnd - navigation.domContentLoadedEventStart,
                    loadComplete: navigation.loadEventEnd - navigation.loadEventStart,
                    totalTime: navigation.loadEventEnd - navigation.fetchStart
                });
            });
        }
    }
    
    recordMetric(name, data) {
        if (!this.metrics.has(name)) {
            this.metrics.set(name, []);
        }
        
        this.metrics.get(name).push(data);
        
        // 通知观察者
        this.observers.forEach(observer => observer(name, data));
    }
    
    getMetrics(name) {
        return this.metrics.get(name) || [];
    }
    
    getAverageMetric(name, field) {
        const metrics = this.getMetrics(name);
        if (metrics.length === 0) return 0;
        
        const sum = metrics.reduce((acc, metric) => acc + metric[field], 0);
        return sum / metrics.length;
    }
}

性能优化最佳实践