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| 1 | +import React, { useEffect, useState, useCallback } from 'react'; |
| 2 | + |
| 3 | +interface TocItem { |
| 4 | + id: string; |
| 5 | + text: string; |
| 6 | + level: number; |
| 7 | +} |
| 8 | + |
| 9 | +interface TableOfContentsProps { |
| 10 | + content: string; |
| 11 | + containerSelector?: string; |
| 12 | +} |
| 13 | + |
| 14 | +const TableOfContents: React.FC<TableOfContentsProps> = ({ |
| 15 | + content, |
| 16 | + containerSelector = '.page-content' |
| 17 | +}) => { |
| 18 | + const [activeId, setActiveId] = useState<string>(''); |
| 19 | + const [tocItems, setTocItems] = useState<TocItem[]>([]); |
| 20 | + |
| 21 | + // 从内容中提取标题 |
| 22 | + const extractHeadings = useCallback((htmlContent: string): TocItem[] => { |
| 23 | + const parser = new DOMParser(); |
| 24 | + const doc = parser.parseFromString(htmlContent, 'text/html'); |
| 25 | + const headings = doc.querySelectorAll('h1, h2, h3, h4, h5, h6'); |
| 26 | + |
| 27 | + const items: TocItem[] = []; |
| 28 | + headings.forEach((heading, index) => { |
| 29 | + const level = parseInt(heading.tagName.substring(1)); |
| 30 | + const text = heading.textContent?.trim() || ''; |
| 31 | + if (text) { |
| 32 | + // 生成唯一 ID |
| 33 | + const id = `toc-heading-${index}`; |
| 34 | + items.push({ id, text, level }); |
| 35 | + } |
| 36 | + }); |
| 37 | + |
| 38 | + return items; |
| 39 | + }, []); |
| 40 | + |
| 41 | + // 初始化时提取标题 |
| 42 | + useEffect(() => { |
| 43 | + const items = extractHeadings(content); |
| 44 | + setTocItems(items); |
| 45 | + }, [content, extractHeadings]); |
| 46 | + |
| 47 | + // 为实际 DOM 中的标题元素添加 ID |
| 48 | + useEffect(() => { |
| 49 | + if (tocItems.length === 0) return; |
| 50 | + |
| 51 | + // 等待 DOM 渲染完成 |
| 52 | + const timer = setTimeout(() => { |
| 53 | + const container = document.querySelector(containerSelector); |
| 54 | + if (!container) return; |
| 55 | + |
| 56 | + const headings = container.querySelectorAll('h1, h2, h3, h4, h5, h6'); |
| 57 | + headings.forEach((heading, index) => { |
| 58 | + if (index < tocItems.length) { |
| 59 | + heading.id = tocItems[index].id; |
| 60 | + } |
| 61 | + }); |
| 62 | + }, 100); |
| 63 | + |
| 64 | + return () => clearTimeout(timer); |
| 65 | + }, [tocItems, containerSelector]); |
| 66 | + |
| 67 | + // 监听滚动事件，更新当前激活的标题 |
| 68 | + useEffect(() => { |
| 69 | + if (tocItems.length === 0) return; |
| 70 | + |
| 71 | + const handleScroll = () => { |
| 72 | + const container = document.querySelector(containerSelector); |
| 73 | + if (!container) return; |
| 74 | + |
| 75 | + const headings = container.querySelectorAll('h1, h2, h3, h4, h5, h6'); |
| 76 | + |
| 77 | + // 找到当前视口中最近的标题 |
| 78 | + let currentActive = ''; |
| 79 | + const offset = 120; // 固定偏移量，考虑顶部固定头部 |
| 80 | + |
| 81 | + for (let i = headings.length - 1; i >= 0; i--) { |
| 82 | + const heading = headings[i] as HTMLElement; |
| 83 | + const rect = heading.getBoundingClientRect(); |
| 84 | + |
| 85 | + if (rect.top <= offset) { |
| 86 | + currentActive = heading.id; |
| 87 | + break; |
| 88 | + } |
| 89 | + } |
| 90 | + |
| 91 | + // 如果没有找到（在页面最顶部），激活第一个标题 |
| 92 | + if (!currentActive && headings.length > 0) { |
| 93 | + const firstHeading = headings[0] as HTMLElement; |
| 94 | + const rect = firstHeading.getBoundingClientRect(); |
| 95 | + if (rect.top < window.innerHeight) { |
| 96 | + currentActive = firstHeading.id; |
| 97 | + } |
| 98 | + } |
| 99 | + |
| 100 | + if (currentActive !== activeId) { |
| 101 | + setActiveId(currentActive); |
| 102 | + } |
| 103 | + }; |
| 104 | + |
| 105 | + // 延迟初始调用确保 DOM 已渲染 |
| 106 | + const initTimer = setTimeout(() => { |
| 107 | + handleScroll(); |
| 108 | + }, 200); |
| 109 | + |
| 110 | + // 监听页面滚动 |
| 111 | + window.addEventListener('scroll', handleScroll, { passive: true }); |
| 112 | + |
| 113 | + // 监听 drawer 内的滚动（如果在 modal 中） |
| 114 | + const drawer = document.querySelector('.MuiDrawer-paper'); |
| 115 | + if (drawer) { |
| 116 | + drawer.addEventListener('scroll', handleScroll, { passive: true }); |
| 117 | + } |
| 118 | + |
| 119 | + return () => { |
| 120 | + clearTimeout(initTimer); |
| 121 | + window.removeEventListener('scroll', handleScroll); |
| 122 | + if (drawer) { |
| 123 | + drawer.removeEventListener('scroll', handleScroll); |
| 124 | + } |
| 125 | + }; |
| 126 | + }, [tocItems, activeId, containerSelector]); |
| 127 | + |
| 128 | + // 点击目录项滚动到对应位置 |
| 129 | + const handleClick = (e: React.MouseEvent, id: string) => { |
| 130 | + e.preventDefault(); |
| 131 | + const element = document.getElementById(id); |
| 132 | + if (element) { |
| 133 | + // 获取 drawer 容器 |
| 134 | + const drawer = document.querySelector('.MuiDrawer-paper'); |
| 135 | + const offsetTop = 80; // 顶部固定栏的高度偏移 |
| 136 | + |
| 137 | + if (drawer) { |
| 138 | + const elementTop = element.getBoundingClientRect().top + drawer.scrollTop - drawer.getBoundingClientRect().top; |
| 139 | + drawer.scrollTo({ |
| 140 | + top: elementTop - offsetTop, |
| 141 | + behavior: 'smooth' |
| 142 | + }); |
| 143 | + } else { |
| 144 | + const elementTop = element.getBoundingClientRect().top + window.scrollY; |
| 145 | + window.scrollTo({ |
| 146 | + top: elementTop - offsetTop, |
| 147 | + behavior: 'smooth' |
| 148 | + }); |
| 149 | + } |
| 150 | + setActiveId(id); |
| 151 | + } |
| 152 | + }; |
| 153 | + |
| 154 | + // 如果标题数量少于等于 2 个，不显示目录 |
| 155 | + if (tocItems.length <= 2) { |
| 156 | + return null; |
| 157 | + } |
| 158 | + |
| 159 | + // 计算最小层级，用于调整缩进 |
| 160 | + const minLevel = Math.min(...tocItems.map(item => item.level)); |
| 161 | + |
| 162 | + return ( |
| 163 | + <div className="toc-wrapper"> |
| 164 | + <nav className="toc-nav"> |
| 165 | + <ul className="toc-list"> |
| 166 | + {tocItems.map((item) => { |
| 167 | + const indent = (item.level - minLevel) * 14; |
| 168 | + const isActive = activeId === item.id; |
| 169 | + |
| 170 | + return ( |
| 171 | + <li |
| 172 | + key={item.id} |
| 173 | + style={{ paddingLeft: `${indent}px` }} |
| 174 | + className="toc-item" |
| 175 | + > |
| 176 | + <a |
| 177 | + href={`#${item.id}`} |
| 178 | + onClick={(e) => handleClick(e, item.id)} |
| 179 | + className={`toc-link ${isActive ? 'toc-link-active' : ''}`} |
| 180 | + title={item.text} |
| 181 | + > |
| 182 | + <span className="line-clamp-2"> |
| 183 | + {item.text} |
| 184 | + </span> |
| 185 | + </a> |
| 186 | + </li> |
| 187 | + ); |
| 188 | + })} |
| 189 | + </ul> |
| 190 | + </nav> |
| 191 | + </div> |
| 192 | + ); |
| 193 | +}; |
| 194 | + |
| 195 | +export default TableOfContents; |
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