\u957f\u5217\u8868\u771f\u6b63\u7684\u95ee\u9898\u4e0d\u662f\u201c\u6570\u636e\u591a\u201d，\u800c\u662f\u4e00\u6b21\u6027\u521b\u5efa\u3001\u6e32\u67d3\u548c\u7ef4\u62a4\u4e86\u8fc7\u591a\u7684 DOM \u8282\u70b9\u4ee5\u53ca\u5bf9\u5e94\u7684 React \u7ec4\u4ef6\u6811，\u56e0\u6b64\u865a\u62df\u5217\u8868\u901a\u8fc7\u201c\u53ea\u6e32\u67d3\u5f53\u524d\u9700\u8981\u770b\u5230\u7684\u5c11\u91cf\u8282\u70b9\u201d\u964d\u4f4e\u5b9e\u9645\u6e32\u67d3\u6210\u672c\u3002<\/p>\n
\u5927\u91cf\u5217\u8868\u6570\u636e
\n \u2193
\n\u4e00\u6b21\u6027\u6e32\u67d3\u5168\u90e8\u5217\u8868\u9879
\n \u2193
\n\u4ea7\u751f\u5927\u91cf React Element \/ Fiber \/ DOM \u8282\u70b9
\n \u2193
\nReact \u6e32\u67d3\u3001\u534f\u8c03\u6210\u672c\u589e\u52a0
\n \u2193
\n\u6d4f\u89c8\u5668 Layout \/ Paint \/ Composite \u6210\u672c\u589e\u52a0
\n \u2193
\n\u5185\u5b58\u5360\u7528\u589e\u52a0
\n \u2193
\n\u6eda\u52a8\u3001\u66f4\u65b0\u65f6\u4e3b\u7ebf\u7a0b\u5de5\u4f5c\u91cf\u589e\u52a0
\n \u2193
\n\u6389\u5e27 \/ \u5361\u987f \/ \u54cd\u5e94\u53d8\u6162
\n \u2193
\n\u865a\u62df\u5217\u8868
\n \u2193
\n\u53ea\u6e32\u67d3\u53ef\u89c6\u533a\u57df + \u5c11\u91cf\u7f13\u51b2\u533a\u57df
\n \u2193
\nDOM \u8282\u70b9\u6570\u91cf\u7ef4\u6301\u5728\u8f83\u5c0f\u8303\u56f4
\n \u2193
\n\u964d\u4f4e\u6e32\u67d3\u3001\u5e03\u5c40\u3001\u7ed8\u5236\u548c\u5185\u5b58\u6210\u672c<\/p>\n
\u4e3b\u8981\u77db\u76fe：DOM \u548c\u7ec4\u4ef6\u5b9e\u9645\u6e32\u67d3\u6570\u91cf\u8fdc\u8fdc\u8d85\u8fc7\u7528\u6237\u5f53\u524d\u771f\u6b63\u9700\u8981\u770b\u5230\u7684\u6570\u91cf\u3002<\/p>\n
\u4f8b\u5982：<\/p>\n
\u603b\u6570\u636e：100000 \u6761<\/p>\n
\u666e\u901a\u5217\u8868：
\n100000 \u6761 \u2192 100000 \u4e2a\u5217\u8868\u9879 \u2192 \u5927\u91cf DOM<\/p>\n
\u865a\u62df\u5217\u8868：
\n100000 \u6761\u6570\u636e
\n \u2193
\n\u5f53\u524d\u89c6\u53e3\u53ea\u80fd\u770b\u5230\u7ea6 20 \u6761
\n \u2193
\n\u5b9e\u9645\u6e32\u67d3 20 ～ 40 \u6761
\n \u2193
\n\u968f\u7740\u6eda\u52a8\u4e0d\u65ad\u66ff\u6362\u6e32\u67d3\u7a97\u53e3<\/p>\n
\u56e0\u6b64\u865a\u62df\u5217\u8868\u7684\u6838\u5fc3\u5e76\u4e0d\u662f\u201c\u8ba9 100000 \u6761\u6570\u636e\u6d88\u5931\u201d，\u800c\u662f：<\/p>\n
\u6570\u636e\u53ef\u4ee5\u6709 100000 \u6761，\u4f46 DOM \u4e0d\u9700\u8981\u540c\u65f6\u5b58\u5728 100000 \u4e2a\u3002<\/p>\n
\u9664\u4e86 DOM \u6570\u91cf\u4e4b\u5916，\u8fd8\u5305\u62ec：<\/p>\n
\u4e00\u4e2a\u5217\u8868\u9879\u5e76\u4e0d\u662f\u7b80\u5355\u7684\u4e00\u4e2a JavaScript \u5bf9\u8c61\u3002<\/p>\n
\u4f8b\u5982：<\/p>\n
<div className="item">
\n <img \/>
\n <span \/>
\n <button \/>
\n<\/div><\/p>\n
10000 \u4e2a\u8fd9\u6837\u7684\u5217\u8868\u9879，\u53ef\u80fd\u610f\u5473\u7740：<\/p>\n
10000 \u4e2a React \u5217\u8868\u7ec4\u4ef6
\n \u2193
\n\u5927\u91cf React Element
\n \u2193
\n\u5927\u91cf Fiber \u8282\u70b9
\n \u2193
\n\u5927\u91cf DOM \u8282\u70b9
\n \u2193
\n\u6d4f\u89c8\u5668\u7ef4\u62a4\u5de8\u5927\u7684 DOM Tree
\n \u2193
\n\u5e03\u5c40 \/ \u6837\u5f0f\u8ba1\u7b97 \/ \u7ed8\u5236\u6210\u672c\u589e\u52a0<\/p>\n
\u7279\u522b\u9700\u8981\u6ce8\u610f：<\/p>\n
\u5b9e\u9645\u4e0a\u5b58\u5728\u4e24\u5c42\u6210\u672c：<\/p>\n
React \u5c42
\n\u251c\u2500\u2500 \u7ec4\u4ef6\u6267\u884c
\n\u251c\u2500\u2500 Element \u521b\u5efa
\n\u251c\u2500\u2500 Fiber \u534f\u8c03
\n\u2514\u2500\u2500 Commit<\/p>\n
\u6d4f\u89c8\u5668\u5c42
\n\u251c\u2500\u2500 Style Calculation
\n\u251c\u2500\u2500 Layout
\n\u251c\u2500\u2500 Paint
\n\u2514\u2500\u2500 Composite<\/p>\n
\u6240\u4ee5\u5373\u4f7f React \u672c\u8eab\u5df2\u7ecf\u8fdb\u884c\u4e86\u5f88\u591a\u4f18\u5316：<\/p>\n
React.memo
\nuseMemo
\nuseCallback<\/p>\n
\u5982\u679c\u6700\u7ec8\u9875\u9762\u4ecd\u7136\u5b58\u5728\u5341\u51e0\u4e07\u4e2a DOM \u8282\u70b9，\u4e5f\u65e0\u6cd5\u4ece\u6839\u672c\u4e0a\u89e3\u51b3\u6d4f\u89c8\u5668\u5c42\u9762\u7684\u538b\u529b\u3002<\/p>\n
\u4e0d\u8981\u7b80\u5355\u56de\u7b54：<\/p>\n
\u201c\u56e0\u4e3a React \u7684 Diff \u7b97\u6cd5\u590d\u6742\u5ea6\u662f O(n)，\u6240\u4ee5\u5217\u8868\u5f88\u5361\u3002\u201d<\/p>\n
\u8fd9\u4e2a\u8bf4\u6cd5\u4e0d\u51c6\u786e\u3002<\/p>\n
\u73b0\u4ee3 React \u4f7f\u7528 Fiber \u67b6\u6784，\u5e76\u4e14\u534f\u8c03\u7b97\u6cd5\u6709\u5927\u91cf\u4f18\u5316，\u4e0d\u80fd\u7b80\u5355\u7528\u201cDiff \u662f O(n)\u201d\u89e3\u91ca\u957f\u5217\u8868\u95ee\u9898\u3002<\/p>\n
\u66f4\u51c6\u786e\u7684\u56de\u7b54\u662f：<\/p>\n
\u957f\u5217\u8868\u6027\u80fd\u95ee\u9898\u6765\u81ea\u591a\u4e2a\u5c42\u9762，\u5305\u62ec\u5927\u91cf\u7ec4\u4ef6\u6267\u884c\u3001Fiber \u534f\u8c03\u3001Commit\u3001DOM \u8282\u70b9\u7ef4\u62a4，\u4ee5\u53ca\u6d4f\u89c8\u5668\u6837\u5f0f\u8ba1\u7b97\u3001\u5e03\u5c40\u548c\u7ed8\u5236\u7b49\u6210\u672c\u3002\u865a\u62df\u5217\u8868\u901a\u8fc7\u51cf\u5c11\u5b9e\u9645\u6302\u8f7d\u7684\u5217\u8868\u9879\u6570\u91cf，\u4ece\u6e90\u5934\u964d\u4f4e\u8fd9\u4e9b\u6210\u672c\u3002<\/p>\n
\u865a\u62df\u5217\u8868\u5c31\u662f\u201c\u6570\u636e\u5168\u91cf\u5b58\u5728，\u4f46 DOM \u53ea\u6e32\u67d3\u5f53\u524d\u89c6\u53e3\u9644\u8fd1\u7684\u5c11\u91cf\u6570\u636e\u201d，\u901a\u8fc7\u8ba1\u7b97\u53ef\u89c6\u533a\u7d22\u5f15\u548c\u5143\u7d20\u4f4d\u7f6e，\u8ba9\u7528\u6237\u611f\u89c9\u6574\u4e2a\u5217\u8868\u90fd\u5b58\u5728\u3002<\/p>\n
\u5b8c\u6574\u6570\u636e
\n \u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510
\n \u2502 0 1 2 3 … 99999 \u2502
\n \u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518
\n \u2502
\n \u2193
\n \u865a\u62df\u5217\u8868\u8ba1\u7b97\u5668
\n \u2502
\n \u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2534\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510
\n \u2193 \u2193
\n scrollTop containerHeight
\n \u2502 \u2502
\n \u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u252c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518
\n \u2193
\n \u8ba1\u7b97\u53ef\u89c6\u8303\u56f4
\n \u2193
\n startIndex ~ endIndex
\n \u2193
\n \u52a0\u4e0a overscan \u7f13\u51b2\u533a
\n \u2193
\n \u5b9e\u9645\u6e32\u67d3\u5c11\u91cf\u8282\u70b9
\n \u2193
\n \u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510
\n \u2502 Item Item Item Item \u2502
\n \u2502 Item Item Item Item \u2502
\n \u2502 Item Item Item Item \u2502
\n \u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518<\/p>\n
\u7528\u6237\u771f\u6b63\u80fd\u591f\u770b\u5230\u7684\u533a\u57df\u3002<\/p>\n
\u4f8b\u5982：<\/p>\n
\u5bb9\u5668\u9ad8\u5ea6：600px
\n\u6bcf\u9879\u9ad8\u5ea6：50px<\/p>\n
\u7406\u8bba\u53ef\u89c1\u6570\u91cf：<\/p>\n
600 \/ 50 = 12<\/p>\n
\u56e0\u6b64\u5f53\u524d\u5927\u7ea6\u53ea\u9700\u8981\u6e32\u67d3 12 \u9879\u3002<\/p>\n
\u5b9e\u9645\u901a\u5e38\u8fd8\u4f1a\u591a\u6e32\u67d3\u51e0\u9879：<\/p>\n
\u53ef\u89c6\u533a
\n+ \u4e0a\u65b9 overscan
\n+ \u4e0b\u65b9 overscan<\/p>\n
\u907f\u514d\u7528\u6237\u5feb\u901f\u6eda\u52a8\u65f6\u51fa\u73b0\u767d\u5c4f\u3002<\/p>\n
\u901a\u5e38：<\/p>\n
.container<\/span> {<\/span> \u867d\u7136\u53ea\u6e32\u67d3 20～40 \u4e2a\u8282\u70b9，\u4f46\u662f\u6eda\u52a8\u6761\u5fc5\u987b\u8868\u73b0\u5f97\u50cf\u6574\u4e2a\u5217\u8868\u90fd\u5b58\u5728\u3002<\/p>\n \u4f8b\u5982：<\/p>\n 100000 \u6761 \u603b\u9ad8\u5ea6：<\/p>\n 100000 \u00d7 50 \u56e0\u6b64\u5185\u90e8\u9700\u8981\u4e00\u4e2a\u5177\u6709\u5de8\u5927\u9ad8\u5ea6\u7684\u5bb9\u5668：<\/p>\n <<\/span>div<\/span> class<\/span>=<\/span>"<\/span>container"<\/span><\/span>><\/span><\/span> \u5176\u4e2d：<\/p>\n container virtual-content \u201c\u901a\u8fc7\u4e00\u4e2a\u603b\u9ad8\u5ea6\u533a\u57df\u6491\u8d77\u539f\u751f\u6eda\u52a8\u6761\u201d\u7684\u6838\u5fc3\u673a\u5236\u3002<\/p>\n \u56fa\u5b9a\u9ad8\u5ea6\u5217\u8868\u53ef\u4ee5\u901a\u8fc7 scrollTop \/ itemHeight \u76f4\u63a5\u8ba1\u7b97\u8d77\u59cb\u7d22\u5f15，\u518d\u6839\u636e\u5bb9\u5668\u9ad8\u5ea6\u8ba1\u7b97\u7ed3\u675f\u7d22\u5f15\u3002<\/p>\n \u5047\u8bbe：<\/p>\n itemHeight = 50px \u90a3\u4e48：<\/p>\n startIndex = floor(scrollTop \/ itemHeight)<\/p>\n = floor(1250 \/ 50)<\/p>\n = 25<\/p>\n \u53ef\u89c1\u6570\u91cf：<\/p>\n visibleCount = ceil(containerHeight \/ itemHeight)<\/p>\n = ceil(500 \/ 50)<\/p>\n = 10<\/p>\n \u6240\u4ee5：<\/p>\n endIndex = startIndex + visibleCount \u5982\u679c\u589e\u52a0 overscan：<\/p>\n overscan = 5<\/p>\n \u5b9e\u9645\u5f00\u59cb： \u5b9e\u9645\u7ed3\u675f： \u6700\u7ec8：<\/p>\n [20 … 40]<\/p>\n \u8fd9\u4e9b\u6570\u636e\u624d\u771f\u6b63\u9700\u8981\u6e32\u67d3\u3002<\/p>\n \u7528\u6237\u6eda\u52a8 \u56e0\u4e3a\u5b9e\u9645 DOM \u53ea\u6709\u51e0\u5341\u9879，\u5982\u679c\u6ca1\u6709\u4e00\u4e2a\u4ee3\u8868\u5b8c\u6574\u5217\u8868\u9ad8\u5ea6\u7684\u5bb9\u5668，\u6d4f\u89c8\u5668\u5c31\u65e0\u6cd5\u4ea7\u751f\u6b63\u786e\u7684\u6eda\u52a8\u6761\u548c scrollTop \u8303\u56f4\u3002<\/p>\n 10000 \u6761：<\/p>\n \u6bcf\u9879\u9ad8\u5ea6：50px<\/p>\n \u603b\u9ad8\u5ea6：<\/p>\n 10000 \u00d7 50 = 500000px<\/p>\n \u4f46\u662f\u5b9e\u9645\u53ea\u6e32\u67d3：<\/p>\n \u7b2c 100～120 \u9879<\/p>\n \u5982\u679c\u9875\u9762\u771f\u5b9e DOM \u9ad8\u5ea6\u53ea\u6709：<\/p>\n 20 \u00d7 50 = 1000px<\/p>\n \u90a3\u4e48\u6d4f\u89c8\u5668\u4f1a\u8ba4\u4e3a：<\/p>\n \u201c\u8fd9\u4e2a\u5217\u8868\u53ea\u6709 1000px\u3002\u201d<\/p>\n \u6eda\u52a8\u6761\u5f53\u7136\u5c31\u4e0d\u6b63\u786e\u3002<\/p>\n \u6240\u4ee5\u9700\u8981：<\/p>\n <<\/span>div<\/span> class<\/span>=<\/span>"<\/span>container"<\/span><\/span>><\/span><\/span> <!– \u5b9e\u9645\u53ea\u5b58\u5728\u5c11\u91cf DOM –><\/span><\/p>\n <\/<\/span>div<\/span>><\/span><\/span> \u901a\u8fc7 position: absolute + top，\u5c06\u5c11\u91cf\u5b9e\u9645\u6e32\u67d3\u7684\u8282\u70b9\u76f4\u63a5\u5b9a\u4f4d\u5230\u5b83\u4eec\u5728\u5b8c\u6574\u5217\u8868\u4e2d\u7684\u903b\u8f91\u4f4d\u7f6e\u3002<\/p>\n \u5b8c\u6574\u5217\u8868<\/p>\n 0px \u5b9e\u9645 DOM：<\/p>\n virtual-content \u56e0\u6b64：<\/p>\n .item<\/span> {<\/span> \u7136\u540e：<\/p>\n style={{ \u8fd9\u6837：<\/p>\n DOM \u6570\u91cf\u5c11，\u4f46\u89c6\u89c9\u4f4d\u7f6e\u4ecd\u7136\u548c\u5b8c\u6574\u5217\u8868\u4e00\u81f4\u3002<\/p>\n \u56fa\u5b9a\u9ad8\u5ea6\u573a\u666f\u4e0b，\u53ea\u9700\u8981\u7ef4\u62a4 scrollTop，\u6839\u636e scrollTop \u8ba1\u7b97\u53ef\u89c6\u7d22\u5f15，\u518d\u7528\u603b\u9ad8\u5ea6\u5bb9\u5668 + \u7edd\u5bf9\u5b9a\u4f4d\u6e32\u67d3\u53ef\u89c6\u6570\u636e\u3002<\/p>\n import React, { useCallback, useEffect, useMemo, useState } from 'react';<\/p>\n \/** \/** requestAnimationFrame(() => { \/** \/** \/** \/** const end = Math.min( return { \/** \/** return ( return ( \/** left: 0, \/** \/** \/** return ( <VirtualList 1. scrollTop \u8fd9\u56db\u6b65\u5c31\u662f\u56fa\u5b9a\u9ad8\u5ea6\u865a\u62df\u5217\u8868\u7684\u6838\u5fc3\u3002<\/p>\n overscan \u5c31\u662f\u5728\u771f\u6b63\u53ef\u89c6\u533a\u57df\u4e4b\u5916\u989d\u5916\u6e32\u67d3\u5c11\u91cf\u5217\u8868\u9879，\u7528\u5c11\u91cf\u989d\u5916 DOM \u6362\u53d6\u5feb\u901f\u6eda\u52a8\u65f6\u7684\u6d41\u7545\u5ea6\u548c\u51cf\u5c11\u767d\u5c4f\u3002<\/p>\n \u5047\u8bbe：<\/p>\n \u5f53\u524d\u53ef\u89c1：<\/p>\n 100 ～ 110<\/p>\n \u8bbe\u7f6e：<\/p>\n overscan = 5<\/p>\n \u5b9e\u9645\u6e32\u67d3：<\/p>\n 95 ～ 115<\/p>\n \u7ed3\u6784：<\/p>\n overscan 95 96 97 98 99 DOM \u5c11 \u767d\u5c4f\u6982\u7387\u964d\u4f4e \u56e0\u6b64：<\/p>\n overscan \u662f\u6027\u80fd\u548c\u6eda\u52a8\u4f53\u9a8c\u4e4b\u95f4\u7684\u5e73\u8861\u53c2\u6570\u3002<\/p>\n \u865a\u62df\u5217\u8868\u628a\u201c\u6570\u636e\u89c4\u6a21\u201d\u548c\u201cDOM \u89c4\u6a21\u201d\u89e3\u8026\u3002<\/p>\n \u6570\u636e\u91cf： DOM： \u6570\u636e\u91cf： DOM： \u4f8b\u5982：<\/p>\n \u5bb9\u5668\u9ad8\u5ea6：600px \u53ef\u89c1： \u5b9e\u9645\u6e32\u67d3： \u2248 22 \u4e2a<\/p>\n \u6240\u4ee5\u5217\u8868\u4ece：<\/p>\n 100000 DOM<\/p>\n \u4e0b\u964d\u5230：<\/p>\n \u7ea6 22 DOM<\/p>\n \u8fd9\u624d\u662f\u865a\u62df\u5217\u8868\u771f\u6b63\u7684\u6027\u80fd\u6536\u76ca\u6765\u6e90\u3002<\/p>\n \u865a\u62df\u5217\u8868\u6700\u6838\u5fc3\u7684\u6536\u76ca\u662f\u628a\u201c\u4e0e\u603b\u6570\u636e\u91cf\u76f8\u5173\u7684\u5b9e\u9645\u6e32\u67d3\u89c4\u6a21\u201d\u964d\u4f4e\u4e3a\u201c\u4e0e\u89c6\u53e3\u5927\u5c0f\u76f8\u5173\u7684\u6e32\u67d3\u89c4\u6a21\u201d\u3002<\/p>\n 100000 \u2192 20～50<\/p>\n \u4e0d\u9700\u8981\u4e00\u6b21\u6027\u521b\u5efa\u6240\u6709\u5217\u8868\u9879\u3002<\/p>\n \u5c11\u91cf DOM\u3001\u7ec4\u4ef6\u548c Fiber \u8282\u70b9\u5e38\u9a7b\u3002<\/p>\n \u6d4f\u89c8\u5668\u9700\u8981\u7ef4\u62a4\u7684\u771f\u5b9e\u8282\u70b9\u660e\u663e\u51cf\u5c11\u3002<\/p>\n \u66f4\u65b0\u65f6\u5b9e\u9645\u53c2\u4e0e\u6e32\u67d3\u7684\u5217\u8868\u9879\u6570\u91cf\u51cf\u5c11\u3002<\/p>\n \u8bf4\u865a\u62df\u5217\u8868\u5c5e\u4e8e：<\/p>\n \u201c\u65f6\u95f4\u6362\u7a7a\u95f4\u201d\u3002<\/p>\n \u8fd9\u4e2a\u8bf4\u6cd5\u4e0d\u591f\u51c6\u786e\u3002<\/p>\n \u66f4\u51c6\u786e\u5e94\u8be5\u8bf4：<\/p>\n \u865a\u62df\u5217\u8868\u901a\u8fc7\u589e\u52a0\u53ef\u89c6\u533a\u57df\u8ba1\u7b97\u3001\u6eda\u52a8\u7ba1\u7406\u3001\u4f4d\u7f6e\u8ba1\u7b97\u3001\u52a8\u6001\u9ad8\u5ea6\u6d4b\u91cf\u7b49\u989d\u5916\u8fd0\u884c\u65f6\u903b\u8f91，\u6362\u53d6\u66f4\u5c11\u7684 DOM\u3001\u7ec4\u4ef6\u5b9e\u4f8b\u548c\u6d4f\u89c8\u5668\u5e03\u5c40\/\u7ed8\u5236\u5f00\u9500\u3002<\/p>\n \u5b83\u4e0d\u662f\u7b80\u5355\u610f\u4e49\u4e0a\u7684\u201c\u65f6\u95f4\u6362\u7a7a\u95f4\u201d\u3002<\/p>\n \u6eda\u52a8\u4e8b\u4ef6\u5c5e\u4e8e\u9ad8\u9891\u4e8b\u4ef6，\u6838\u5fc3\u4e0d\u662f\u7b80\u5355\u4f7f\u7528\u9632\u6296，\u800c\u662f\u63a7\u5236\u6eda\u52a8\u8fc7\u7a0b\u4e2d\u7684\u8ba1\u7b97\u548c React \u66f4\u65b0\u9891\u7387，\u901a\u5e38\u4f18\u5148\u8003\u8651 requestAnimationFrame \u6216\u5408\u7406\u8282\u6d41\u3002<\/p>\n \u8fd9\u91cc\u9700\u8981\u7279\u522b\u6ce8\u610f：<\/p>\n \u56e0\u4e3a：<\/p>\n \u7528\u6237\u5f00\u59cb\u5feb\u901f\u6eda\u52a8 \u66f4\u9002\u5408：<\/p>\n scroll scroll event \u52a8\u6001\u9ad8\u5ea6\u7684\u6838\u5fc3\u96be\u70b9\u662f：\u5728\u4e0d\u77e5\u9053\u6240\u6709\u771f\u5b9e\u9ad8\u5ea6\u7684\u60c5\u51b5\u4e0b，\u4ecd\u7136\u8981\u5feb\u901f\u8ba1\u7b97\u6bcf\u4e00\u9879\u7684\u4f4d\u7f6e，\u56e0\u6b64\u9700\u8981\u201c\u9884\u4f30\u9ad8\u5ea6 + \u5b9e\u9645\u6d4b\u91cf + \u9ad8\u5ea6\u7f13\u5b58 + \u4f4d\u7f6e\u91cd\u65b0\u8ba1\u7b97\u201d\u3002<\/p>\n \u975e\u5e38\u7b80\u5355：<\/p>\n index \u4f8b\u5982：<\/p>\n \u7b2c 100 \u9879：<\/p>\n top = 100 \u00d7 50 \u5047\u8bbe：<\/p>\n Item 0 = 50px \u90a3\u4e48：<\/p>\n Item 0: Item 1: Item 2: Item 3: \u6240\u4ee5：<\/p>\n \u52a8\u6001\u9ad8\u5ea6\u5217\u8868\u7684\u6838\u5fc3\u662f\u524d\u7f00\u548c\u3002<\/p>\n \u6570\u636e const<\/span> heightCache =<\/span> new<\/span> Map<\/span>(<\/span>)<\/span>;<\/span><\/p>\n heightCache.<\/span>set<\/span>(<\/span>0<\/span>,<\/span> 50<\/span>)<\/span>;<\/span> \u7136\u540e：<\/p>\n heightCache \u56fa\u5b9a\u9ad8\u5ea6\u53ef\u4ee5 O(1) \u76f4\u63a5\u5b9a\u4f4d，\u800c\u52a8\u6001\u9ad8\u5ea6\u9700\u8981\u7ef4\u62a4\u9ad8\u5ea6\u4fe1\u606f\u5e76\u8ba1\u7b97\u7d2f\u8ba1\u9ad8\u5ea6，\u56e0\u6b64\u5b9a\u4f4d\u3001\u6eda\u52a8\u3001\u7f13\u5b58\u548c\u6d4b\u91cf\u90fd\u4f1a\u53d8\u590d\u6742\u3002<\/p>\n startIndex = floor(scrollTop \/ itemHeight)<\/p>\n \u76f4\u63a5 O(1)\u3002<\/p>\n \u4f8b\u5982：<\/p>\n scrollTop = 10000<\/p>\n \u4f60\u9700\u8981\u77e5\u9053：<\/p>\n \u7b2c\u51e0\u4e2a item \u7684\u7d2f\u8ba1\u9ad8\u5ea6\u521a\u597d\u8d85\u8fc7 10000？<\/p>\n \u903b\u8f91\u7c7b\u4f3c：<\/p>\n height[0] \u8fd9\u5c31\u6d89\u53ca：<\/p>\n \u524d\u7f00\u548c \u5982\u679c\u5217\u8868\u975e\u5e38\u5927，\u53ef\u4ee5\u4f7f\u7528：<\/p>\n \u9ad8\u5ea6\u524d\u7f00\u548c\u6570\u7ec4 \u4ece\u800c\u907f\u514d\u6bcf\u6b21\u4ece\u5934\u7d2f\u52a0\u3002<\/p>\n \u5148\u4f7f\u7528\u4f30\u7b97\u9ad8\u5ea6\u5efa\u7acb\u521d\u59cb\u5e03\u5c40，\u771f\u6b63\u6e32\u67d3\u540e\u518d\u6d4b\u91cf\u5b9e\u9645\u9ad8\u5ea6，\u7136\u540e\u66f4\u65b0\u7f13\u5b58\u548c\u540e\u7eed\u5143\u7d20\u7684\u4f4d\u7f6e\u3002<\/p>\n \u672a\u77e5\u771f\u5b9e\u9ad8\u5ea6 \u53ef\u4ee5\u4f7f\u7528：<\/p>\n ResizeObserver<\/p>\n \u4f8b\u5982：<\/p>\n const<\/span> observer =<\/span> new<\/span> ResizeObserver<\/span>(<\/span>(<\/span>entries<\/span>)<\/span> =><\/span> {<\/span> \/\/ \u66f4\u65b0\u5bf9\u5e94\u5217\u8868\u9879\u7684\u9ad8\u5ea6\u7f13\u5b58<\/span> \u76f8\u6bd4\u624b\u52a8\u9891\u7e41\u8bfb\u53d6：<\/p>\n element.<\/span>getBoundingClientRect<\/span>(<\/span>)<\/span><\/p>\n ResizeObserver \u66f4\u9002\u5408\u76d1\u542c\u5c3a\u5bf8\u53d8\u5316\u3002<\/p>\n \u751f\u4ea7\u73af\u5883\u4f18\u5148\u4f7f\u7528\u6210\u719f\u865a\u62df\u5316\u65b9\u6848，\u624b\u5199\u5b9e\u73b0\u4e3b\u8981\u7528\u4e8e\u7406\u89e3\u539f\u7406\u3001\u7279\u6b8a\u573a\u666f\u5b9a\u5236\u4ee5\u53ca\u9762\u8bd5\u8003\u5bdf\u3002<\/p>\n \u4f18\u70b9：<\/p>\n \u5b8c\u5168\u53ef\u63a7 \u7f3a\u70b9：<\/p>\n \u56fa\u5b9a\u9ad8\u5ea6 \u8fd9\u4e9b\u90fd\u4f1a\u9010\u6e10\u53d8\u590d\u6742\u3002<\/p>\n \u5176\u4e2d React Window \u4e3a\u8f7b\u91cf\u65b9\u6848，React Virtualized \u4e3a\u529f\u80fd\u66f4\u52a0\u4e30\u5bcc\u7684\u65b9\u6848，\u8fd8\u6709\u65e0\u5934\u865a\u62df\u5316\u65b9\u6848\u3002<\/p>\n \u9700\u8981\u6ce8\u610f\u7684\u662f：<\/p>\n \u5177\u4f53\u5e93\u7684 API \u548c\u80fd\u529b\u4f1a\u968f\u7248\u672c\u53d8\u5316，\u9762\u8bd5\u65f6\u91cd\u70b9\u5e94\u8be5\u653e\u5728\u865a\u62df\u5316\u539f\u7406，\u800c\u4e0d\u662f\u6b7b\u8bb0\u67d0\u4e2a\u5e93\u7684 API\u3002<\/p>\n \u56fa\u5b9a\u9ad8\u5ea6\u573a\u666f\u76f4\u63a5\u544a\u8bc9\u865a\u62df\u5217\u8868\u5bb9\u5668\u9ad8\u5ea6\u3001\u6570\u636e\u6570\u91cf\u4ee5\u53ca\u6bcf\u9879\u9ad8\u5ea6，\u7531\u5e93\u8d1f\u8d23\u8ba1\u7b97\u53ef\u89c6\u8303\u56f4\u548c\u8282\u70b9\u5b9a\u4f4d\u3002<\/p>\n \u5178\u578b\u601d\u60f3：<\/p>\n <FixedSizeList import React, { useMemo } from 'react'; \/** \/** export default function App() { return ( \/** \/** \/** \u5982\u679c\u5217\u8868\u9879\u9ad8\u5ea6\u7a33\u5b9a，\u4f18\u5148\u56fa\u5b9a\u9ad8\u5ea6；\u53ea\u6709\u786e\u5b9e\u5b58\u5728\u4e0d\u540c\u9ad8\u5ea6\u65f6\u624d\u5f15\u5165\u52a8\u6001\u9ad8\u5ea6，\u56e0\u4e3a\u52a8\u6001\u9ad8\u5ea6\u4f1a\u663e\u8457\u589e\u52a0\u6d4b\u91cf\u548c\u5e03\u5c40\u590d\u6742\u5ea6\u3002<\/p>\n \u9002\u5408：<\/p>\n \u5546\u54c1\u5217\u8868 \u4f8b\u5982：<\/p>\n \u6bcf\u9879\u7edf\u4e00 48px<\/p>\n \u8fd9\u662f\u865a\u62df\u5316\u6700\u5bb9\u6613\u5b9e\u73b0\u3001\u6027\u80fd\u4e5f\u6700\u7a33\u5b9a\u7684\u60c5\u51b5\u3002<\/p>\n \u9002\u5408：<\/p>\n \u804a\u5929\u6d88\u606f \u865a\u62df\u5217\u8868\u89e3\u51b3\u7684\u662f\u201c\u5927\u91cf DOM \u6e32\u67d3\u201d\u95ee\u9898，\u4f46\u4f1a\u589e\u52a0\u5e03\u5c40\u3001\u6eda\u52a8\u3001\u7126\u70b9\u3001\u52a8\u6001\u9ad8\u5ea6\u548c\u53ef\u8bbf\u95ee\u6027\u7b49\u590d\u6742\u5ea6，\u5e76\u4e0d\u80fd\u89e3\u51b3\u5217\u8868\u9879\u81ea\u8eab\u8ba1\u7b97\u8fc7\u91cd\u7684\u95ee\u9898\u3002<\/p>\n \u9700\u8981\u6d4b\u91cf \u4f8b\u5982：<\/p>\n \u7528\u6237\u5feb\u901f\u62d6\u52a8\u6eda\u52a8\u6761 \u89e3\u51b3：<\/p>\n overscan \u4f8b\u5982：<\/p>\n <Item> \u5373\u4f7f\u4e00\u6b21\u53ea\u6709：<\/p>\n 20 \u4e2a Item<\/p>\n \u5982\u679c\u6bcf\u4e2a Item \u90fd\u5f88\u91cd：<\/p>\n 20 \u00d7 \u5f88\u91cd<\/p>\n \u4ecd\u7136\u53ef\u80fd\u5361\u987f\u3002<\/p>\n \u6240\u4ee5：<\/p>\n \u865a\u62df\u5217\u8868\u89e3\u51b3\u7684\u662f\u201c\u8282\u70b9\u592a\u591a\u201d，\u4e0d\u662f\u201c\u5355\u8282\u70b9\u592a\u91cd\u201d\u3002<\/p>\n \u4f8b\u5982：<\/p>\n Tab \u5982\u679c\u5143\u7d20\u5b9e\u9645\u4e0a\u6ca1\u6709\u6302\u8f7d：<\/p>\n \u7528\u6237\u65e0\u6cd5\u76f4\u63a5 focus \u4e00\u4e2a\u5f53\u524d\u6ca1\u6709 DOM \u8282\u70b9\u7684\u5217\u8868\u9879\u3002<\/p>\n \u56e0\u6b64\u9700\u8981\u8bbe\u8ba1：<\/p>\n activeIndex \u4f8b\u5982\u7528\u6237：<\/p>\n Command + F<\/p>\n \u641c\u7d22：<\/p>\n \u7b2c 90000 \u6761\u6570\u636e<\/p>\n \u5982\u679c\u7b2c 90000 \u6761\u76ee\u524d\u6ca1\u6709 DOM：<\/p>\n \u6d4f\u89c8\u5668\u539f\u751f\u67e5\u627e\u53ef\u80fd\u627e\u4e0d\u5230\u5b83\u3002<\/p>\n \u56e0\u6b64\u4e00\u4e9b\u4e1a\u52a1\u9700\u8981\u989d\u5916\u5b9e\u73b0：<\/p>\n \u641c\u7d22 \u6709\u8d44\u6599\u6307\u51fa\u865a\u62df\u5217\u8868\u5bf9\u4e8e\u9700\u8981\u641c\u7d22\u5f15\u64ce\u4f18\u5316\u7684\u516c\u5f00\u9875\u9762\u53ef\u80fd\u5b58\u5728\u95ee\u9898，\u56e0\u4e3a\u521d\u59cb DOM \u4e2d\u5e76\u6ca1\u6709\u6240\u6709\u5217\u8868\u5185\u5bb9\u3002<\/p>\n \u66f4\u51c6\u786e\u5730\u8bf4：<\/p>\n \u5982\u679c\u9875\u9762\u4f9d\u8d56\u5ba2\u6237\u7aef\u865a\u62df\u5316\u624d\u80fd\u4ea7\u751f\u5927\u91cf\u5185\u5bb9，\u641c\u7d22\u5f15\u64ce\u6293\u53d6\u548c\u5185\u5bb9\u53d1\u73b0\u53ef\u80fd\u53d7\u5230\u5f71\u54cd\u3002<\/p>\n \u4f46\u5e76\u4e0d\u662f：<\/p>\n \u201c\u7528\u4e86\u865a\u62df\u5217\u8868\u5c31\u4e00\u5b9a\u6ca1\u6709\u641c\u7d22\u5f15\u64ce\u4f18\u5316\u3002\u201d<\/p>\n \u5982\u679c\u4f7f\u7528：<\/p>\n \u670d\u52a1\u7aef\u6e32\u67d3 \u4ecd\u7136\u53ef\u4ee5\u6539\u5584\u641c\u7d22\u5f15\u64ce\u53ef\u53d1\u73b0\u6027\u3002<\/p>\n \u5bf9\u4e8e\u771f\u6b63\u7684\u516c\u5f00\u5185\u5bb9\u9875\u9762，\u5206\u9875\u901a\u5e38\u6bd4\u65e0\u9650\u865a\u62df\u5217\u8868\u66f4\u5bb9\u6613\u505a\u597d\u641c\u7d22\u5f15\u64ce\u4f18\u5316\u548c\u53ef\u5206\u4eab\u6027\u3002<\/p>\n \u5206\u9875\u89e3\u51b3\u7684\u662f\u201c\u6570\u636e\u83b7\u53d6\u91cf\u201d，\u865a\u62df\u5217\u8868\u89e3\u51b3\u7684\u662f\u201cDOM \u6e32\u67d3\u91cf\u201d，\u65e0\u9650\u6eda\u52a8\u4e3b\u8981\u89e3\u51b3\u7684\u662f\u201c\u7528\u6237\u8fde\u7eed\u6d4f\u89c8\u6570\u636e\u201d\u7684\u4ea4\u4e92\u65b9\u5f0f，\u4e09\u8005\u53ef\u4ee5\u7ec4\u5408\u4f7f\u7528\u3002<\/p>\n \u670d\u52a1\u5668 \u4e3b\u8981\u89e3\u51b3：<\/p>\n \u7f51\u7edc\u4f20\u8f93 \u5df2\u7ecf\u6709 100000 \u6761\u6570\u636e \u4e3b\u8981\u89e3\u51b3：<\/p>\n DOM \u7528\u6237\u6eda\u52a8\u5230\u5e95\u90e8 \u4e3b\u8981\u89e3\u51b3：<\/p>\n \u8fde\u7eed\u6d4f\u89c8\u4f53\u9a8c<\/p>\n \u670d\u52a1\u5668\u5206\u9875 \u8fd9\u662f\u5b9e\u9645\u9879\u76ee\u4e2d\u975e\u5e38\u5e38\u89c1\u7684\u65b9\u6848\u3002<\/p>\n \u4e0d\u80fd\u4ec5\u6839\u636e\u6570\u636e\u6761\u6570\u51b3\u5b9a\u662f\u5426\u865a\u62df\u5316，\u5e94\u8be5\u6839\u636e\u5b9e\u9645 DOM \u6570\u91cf\u3001\u5217\u8868\u9879\u590d\u6742\u5ea6\u3001\u4ea4\u4e92\u9700\u6c42\u548c\u6027\u80fd\u6307\u6807\u51b3\u5b9a\u3002<\/p>\n \u8d85\u8fc7 1000 \u2192 \u865a\u62df\u5217\u8868 \u5e94\u8be5\u8003\u8651：<\/p>\n \u5217\u8868\u9879\u662f\u5426\u590d\u6742？ \u4f8b\u5982：<\/p>\n 1000 \u4e2a\u975e\u5e38\u7b80\u5355\u7684 div<\/p>\n \u53ef\u80fd\u5b8c\u5168\u6ca1\u6709\u95ee\u9898\u3002<\/p>\n \u4f46\u662f：<\/p>\n 500 \u4e2a\u590d\u6742\u5361\u7247 \u4e5f\u53ef\u80fd\u5df2\u7ecf\u9700\u8981\u4f18\u5316\u3002<\/p>\n \u53ef\u4ee5，\u800c\u4e14\u4e24\u8005\u89e3\u51b3\u7684\u662f\u4e0d\u540c\u95ee\u9898：\u865a\u62df\u5217\u8868\u51cf\u5c11\u201c\u540c\u65f6\u5b58\u5728\u591a\u5c11\u8282\u70b9\u201d，React.memo \u51cf\u5c11\u201c\u5df2\u7ecf\u5b58\u5728\u7684\u8282\u70b9\u9700\u8981\u91cd\u590d\u6e32\u67d3\u591a\u5c11\u6b21\u201d\u3002<\/p>\n \u865a\u62df\u5217\u8868 React.memo \u6240\u4ee5：<\/p>\n 100000 \u6761 \u5982\u679c：<\/p>\n Item \u672c\u8eab\u975e\u5e38\u7b80\u5355<\/p>\n \u90a3\u4e48：<\/p>\n React.memo<\/p>\n \u589e\u52a0\u7684\u6bd4\u8f83\u6210\u672c\u53ef\u80fd\u6ca1\u6709\u660e\u663e\u6536\u76ca\u3002<\/p>\n \u5e94\u8be5\u901a\u8fc7：<\/p>\n React DevTools Profiler<\/p>\n \u786e\u8ba4\u771f\u6b63\u7684\u6027\u80fd\u74f6\u9888\u3002<\/p>\n \u865a\u62df\u5217\u8868\u51cf\u5c11\u5de5\u4f5c\u91cf，React \u5e76\u53d1\u6e32\u67d3\u8d1f\u8d23\u66f4\u5408\u7406\u5730\u8c03\u5ea6\u5de5\u4f5c，\u4e24\u8005\u5c5e\u4e8e\u4e0d\u540c\u5c42\u9762\u7684\u4f18\u5316，\u53ef\u4ee5\u7ec4\u5408\u4f46\u4e0d\u80fd\u4e92\u76f8\u66ff\u4ee3\u3002<\/p>\n \u89e3\u51b3：<\/p>\n \u5de5\u4f5c\u592a\u591a<\/p>\n \u6838\u5fc3：<\/p>\n 100000 DOM \u89e3\u51b3：<\/p>\n \u5de5\u4f5c\u6267\u884c\u8fc7\u7a0b\u4e2d\u5982\u4f55\u907f\u514d\u957f\u65f6\u95f4\u963b\u585e\u7528\u6237\u4ea4\u4e92<\/p>\n \u4f8b\u5982：<\/p>\n \u7528\u6237\u8f93\u5165 \u53ef\u4ee5\u8ba9 React \u66f4\u5408\u7406\u5730\u5b89\u6392\u66f4\u65b0\u3002<\/p>\n \u865a\u62df\u5217\u8868 \u5e76\u53d1\u6e32\u67d3 React.memo requestAnimationFrame \u5206\u9875 \/ \u65e0\u9650\u6eda\u52a8 \u8fd9\u662f\u975e\u5e38\u597d\u7684\u6027\u80fd\u4f18\u5316\u4f53\u7cfb\u3002<\/p>\n \u7528\u201c\u603b\u9ad8\u5ea6\u201d\u6a21\u62df\u5b8c\u6574\u5217\u8868，\u7528\u201c\u53ef\u89c6\u533a\u7d22\u5f15\u201d\u51b3\u5b9a\u6e32\u67d3\u54ea\u4e9b\u9879，\u7528\u201c\u7edd\u5bf9\u5b9a\u4f4d\u201d\u628a\u5c11\u91cf\u771f\u5b9e DOM \u653e\u5230\u5b8c\u6574\u5217\u8868\u5bf9\u5e94\u7684\u4f4d\u7f6e\u3002<\/p>\n \u6570\u636e\u6e90 \u5148\u5b9e\u73b0\u56fa\u5b9a\u9ad8\u5ea6\u7248\u672c，\u518d\u62bd\u8c61\u6210\u52a8\u6001\u9ad8\u5ea6\u7248\u672c，\u6700\u540e\u8865\u9f50\u6eda\u52a8\u3001\u7f13\u5b58\u3001overscan\u3001\u952e\u76d8\u5bfc\u822a\u3001\u6570\u636e\u53d8\u5316\u548c\u53ef\u8bbf\u95ee\u6027\u3002<\/p>\n \u5148\u89e3\u51b3：<\/p>\n scrollTop visible range \u52a0\u5165：<\/p>\n estimatedHeight \u5904\u7406：<\/p>\n \u63d2\u5165 \u5904\u7406：<\/p>\n requestAnimationFrame \u4e0d\u63a8\u8350：<\/p>\n items.map((item, index) => ( \u5c24\u5176\u5f53\u5217\u8868\u5b58\u5728：<\/p>\n \u63d2\u5165 \u65f6\u5bb9\u6613\u9020\u6210\u7ec4\u4ef6\u72b6\u6001\u9519\u4e71\u3002<\/p>\n \u5e94\u8be5\u4f18\u5148：<\/p>\n key={item.id}<\/p>\n \u9519\u8bef：<\/p>\n onScroll=<\/span>{<\/span>(<\/span>)<\/span> =><\/span> {<\/span> \u5e94\u8be5：<\/p>\n scroll \u53ef\u80fd：<\/p>\n \u5feb\u901f\u6eda\u52a8 \u53ef\u80fd：<\/p>\n \u5b9e\u9645\u6e32\u67d3\u8282\u70b9\u8fc7\u591a \u4f8b\u5982：<\/p>\n \u9884\u4f30\u9ad8\u5ea6：50px \u6d4b\u91cf\u540e：<\/p>\n \u540e\u7eed\u6240\u6709\u5143\u7d20\u4f4d\u7f6e\u53d1\u751f\u53d8\u5316<\/p>\n \u5982\u679c\u6ca1\u6709\u6b63\u786e\u5904\u7406：<\/p>\n \u7528\u6237\u5f53\u524d\u4f4d\u7f6e\u53ef\u80fd\u7a81\u7136\u8df3\u52a8<\/p>\n \u4f8b\u5982：<\/p>\n <Item> \u8fd9\u65f6\u5019\u8fd8\u9700\u8981：<\/p>\n React.memo \u9700\u8981\u8003\u8651：<\/p>\n \u952e\u76d8\u5bfc\u822a \u4e0d\u662f，\u5b83\u4eec\u4f18\u5316\u7684\u662f\u4e0d\u540c\u5c42\u9762：\u5206\u9875\u4f18\u5316\u6570\u636e\u83b7\u53d6，\u61d2\u52a0\u8f7d\u4f18\u5316\u8d44\u6e90\u52a0\u8f7d，\u865a\u62df\u5217\u8868\u4f18\u5316 DOM \u6e32\u67d3\u3002<\/p>\n \u5b9e\u9645\u9879\u76ee\u901a\u5e38\u7ec4\u5408\u4f7f\u7528\u3002<\/p>\n \u5148\u5224\u65ad\u74f6\u9888\u662f\u6570\u636e\u83b7\u53d6\u3001DOM \u6570\u91cf\u3001\u7ec4\u4ef6\u91cd\u590d\u6e32\u67d3\u8fd8\u662f\u5355\u9879\u8ba1\u7b97，\u518d\u9488\u5bf9\u6027\u91c7\u7528\u5206\u9875\/\u865a\u62df\u5217\u8868\u3001React.memo\u3001\u6570\u636e\u7f13\u5b58\u548c\u8d44\u6e90\u61d2\u52a0\u8f7d\u7b49\u65b9\u6848\u3002<\/p>\n \u7b2c\u4e00\u6b65：\u5b9a\u4f4d\u74f6\u9888 DOM \u592a\u591a？ \u7ec4\u4ef6\u91cd\u590d\u6e32\u67d3？ \u5355\u4e2a Item \u5f88\u91cd？ \u56fe\u7247\u592a\u591a？ \u6eda\u52a8\u66f4\u65b0\u592a\u9891\u7e41？ \u52a8\u6001\u9ad8\u5ea6？ \u516c\u5f00 SEO \u9875\u9762？ \u7528\u6237\u9700\u8981\u201c\u770b\u5230\u4e00\u4e2a\u5b8c\u6574\u7684\u957f\u5217\u8868\u201d，\u4f46\u6d4f\u89c8\u5668\u6ca1\u6709\u5fc5\u8981\u201c\u771f\u5b9e\u7ef4\u62a4\u4e00\u4e2a\u5b8c\u6574\u7684\u957f\u5217\u8868\u201d\u3002<\/p>\n \u7528\u6237\u8ba4\u77e5：<\/p>\n \u6211\u770b\u5230\u7684\u662f 100000 \u6761\u5217\u8868<\/p>\n \u4f46\u6d4f\u89c8\u5668\u5b9e\u9645\u9700\u8981：<\/p>\n \u53ea\u7ef4\u62a4：<\/p>\n \u5f53\u524d\u53ef\u89c6\u533a\u57df \u4e8e\u662f：<\/p>\n \u903b\u8f91\u5217\u8868 \u2260 \u771f\u5b9e DOM \u5217\u8868<\/p>\n \u8fd9\u5c31\u662f\u865a\u62df\u5217\u8868\u6700\u6838\u5fc3\u7684\u8bbe\u8ba1\u601d\u60f3\u3002<\/p>\n \u5b9e\u73b0\u8fc7\u7a0b\u4e2d\u8fd8\u8981\u5904\u7406：<\/p>\n \u903b\u8f91\u4f4d\u7f6e \u6027\u80fd DOM \u6570\u91cf \u56fa\u5b9a\u9ad8\u5ea6 \u6e32\u67d3\u6027\u80fd \u865a\u62df\u5316 \u56e0\u4e3a\u6eda\u52a8\u8fc7\u7a0b\u4e2d\u53d8\u5316\u7684\u4e0d\u662f 10 \u4e07\u4e2a DOM，\u800c\u53ea\u662f\u4e00\u4e2a\u5f88\u5c0f\u7684\u201c\u6e32\u67d3\u7a97\u53e3\u201d\u3002<\/p>\n 100000 \u6761 100000 \u6761\u6570\u636e 100～120<\/p>\n \u79fb\u52a8\u5230：<\/p>\n 110～130<\/p>\n \u2193 \u6240\u4ee5：<\/p>\n \u6027\u80fd\u7684\u5173\u952e\u4e0d\u662f\u201c100000 \u6761\u6570\u636e\u672c\u8eab\u201d，\u800c\u662f\u201c\u540c\u65f6\u53c2\u4e0e\u6e32\u67d3\u7684\u8282\u70b9\u6570\u91cf\u201d\u3002<\/p>\n \u5728 React \u4e2d，\u5982\u679c\u4e00\u6b21\u6027\u6e32\u67d3\u51e0\u5343\u751a\u81f3\u51e0\u4e07\u6761\u5217\u8868\u6570\u636e，\u4f1a\u4ea7\u751f\u5927\u91cf React \u7ec4\u4ef6\u3001Fiber \u8282\u70b9\u548c\u771f\u5b9e DOM，\u540c\u65f6\u6d4f\u89c8\u5668\u8fd8\u9700\u8981\u627f\u62c5\u8f83\u5927\u7684\u6837\u5f0f\u8ba1\u7b97\u3001\u5e03\u5c40\u548c\u7ed8\u5236\u6210\u672c，\u56e0\u6b64\u4f1a\u5bfc\u81f4\u521d\u59cb\u5316\u6162\u3001\u5185\u5b58\u5360\u7528\u589e\u52a0\u4ee5\u53ca\u6eda\u52a8\u5361\u987f\u3002<\/p>\n \u865a\u62df\u5217\u8868\u7684\u6838\u5fc3\u601d\u60f3\u662f\u6309\u9700\u6e32\u67d3：\u6570\u636e\u53ef\u4ee5\u5168\u90e8\u5b58\u5728，\u4f46\u53ea\u6e32\u67d3\u5f53\u524d\u89c6\u53e3\u5185\u4ee5\u53ca\u4e0a\u4e0b\u5c11\u91cf\u7f13\u51b2\u533a\u57df\u7684\u5217\u8868\u9879\u3002\u8fd9\u6837\u5c31\u628a\u5b9e\u9645 DOM \u6570\u91cf\u4ece\u4e0e\u603b\u6570\u636e\u91cf\u76f8\u5173，\u964d\u4f4e\u5230\u4e86\u4e0e\u89c6\u53e3\u5927\u5c0f\u76f8\u5173\u3002<\/p>\n \u5b83\u901a\u5e38\u6709\u4e00\u4e2a\u56fa\u5b9a\u9ad8\u5ea6\u7684\u6eda\u52a8\u5bb9\u5668，\u5185\u90e8\u518d\u653e\u4e00\u4e2a\u4ee3\u8868\u5b8c\u6574\u5217\u8868\u9ad8\u5ea6\u7684\u5bb9\u5668，\u7528\u5b83\u6491\u8d77\u6b63\u786e\u7684\u6eda\u52a8\u6761\u3002\u7528\u6237\u6eda\u52a8\u65f6，\u6839\u636e scrollTop\u3001\u5bb9\u5668\u9ad8\u5ea6\u548c\u5217\u8868\u9879\u9ad8\u5ea6\u8ba1\u7b97\u5f53\u524d\u7684 startIndex \u548c endIndex，\u7136\u540e\u53ea\u4ece\u5b8c\u6574\u6570\u636e\u4e2d\u622a\u53d6\u8fd9\u4e00\u90e8\u5206\u8fdb\u884c\u6e32\u67d3\u3002<\/p>\n \u5bf9\u4e8e\u56fa\u5b9a\u9ad8\u5ea6\u5217\u8868，\u53ef\u4ee5\u76f4\u63a5\u901a\u8fc7：<\/p>\n startIndex = floor(scrollTop \/ itemHeight)<\/p>\n \u6765\u8ba1\u7b97\u8d77\u59cb\u4f4d\u7f6e，\u518d\u6839\u636e\u53ef\u89c6\u533a\u57df\u9ad8\u5ea6\u8ba1\u7b97\u7ed3\u675f\u4f4d\u7f6e，\u5e76\u589e\u52a0 overscan，\u907f\u514d\u5feb\u901f\u6eda\u52a8\u65f6\u51fa\u73b0\u767d\u5c4f\u3002<\/p>\n \u5b9e\u9645\u6e32\u67d3\u51fa\u6765\u7684\u8282\u70b9\u901a\u5e38\u4f7f\u7528 position: absolute \u5b9a\u4f4d，\u901a\u8fc7：<\/p>\n top = index \u00d7 itemHeight<\/p>\n \u653e\u5230\u5b83\u5728\u5b8c\u6574\u5217\u8868\u4e2d\u7684\u903b\u8f91\u4f4d\u7f6e\u3002<\/p>\n \u5982\u679c\u662f\u52a8\u6001\u9ad8\u5ea6\u5217\u8868，\u5c31\u4e0d\u80fd\u7b80\u5355\u4f7f\u7528 index \u00d7 itemHeight，\u9700\u8981\u901a\u8fc7\u9884\u4f30\u9ad8\u5ea6\u3001\u771f\u5b9e DOM \u6d4b\u91cf\u3001\u9ad8\u5ea6\u7f13\u5b58\u4ee5\u53ca\u4f4d\u7f6e\u91cd\u65b0\u8ba1\u7b97\u6765\u7ef4\u62a4\u5e03\u5c40，\u5de5\u7a0b\u4e0a\u901a\u5e38\u4f1a\u4f7f\u7528\u6210\u719f\u7684\u865a\u62df\u5316\u65b9\u6848，\u800c\u4e0d\u662f\u5b8c\u5168\u624b\u5199\u3002<\/p>\n \u53e6\u5916，\u865a\u62df\u5217\u8868\u5e76\u4e0d\u662f\u4e07\u80fd\u7684\u3002\u5982\u679c\u5217\u8868\u9879\u672c\u8eab\u975e\u5e38\u590d\u6742，\u5373\u4f7f\u53ea\u6e32\u67d3\u51e0\u5341\u4e2a\u8282\u70b9\u4ecd\u7136\u53ef\u80fd\u5361\u987f，\u8fd9\u65f6\u5019\u8fd8\u9700\u8981\u7ed3\u5408 React.memo\u3001useMemo\u3001\u56fe\u7247\u61d2\u52a0\u8f7d\u3001\u6570\u636e\u9884\u8ba1\u7b97\u7b49\u65b9\u5f0f\u4f18\u5316\u5217\u8868\u9879\u672c\u8eab\u3002\u5bf9\u4e8e\u52a8\u6001\u9ad8\u5ea6\u3001\u952e\u76d8\u5bfc\u822a\u3001\u7126\u70b9\u7ba1\u7406\u3001\u6d4f\u89c8\u5668\u67e5\u627e\u4ee5\u53ca\u641c\u7d22\u5f15\u64ce\u4f18\u5316\u7b49\u573a\u666f，\u4e5f\u9700\u8981\u989d\u5916\u8bbe\u8ba1\u3002<\/p>\n \u6240\u4ee5\u6211\u4f1a\u628a\u957f\u5217\u8868\u4f18\u5316\u7406\u89e3\u4e3a\u4e00\u4e2a\u5b8c\u6574\u7684\u6027\u80fd\u4f18\u5316\u4f53\u7cfb：<\/p>\n \u6570\u636e\u83b7\u53d6\u8fc7\u591a DOM \u6570\u91cf\u8fc7\u591a \u7ec4\u4ef6\u91cd\u590d\u6e32\u67d3 \u5355\u4e2a\u5217\u8868\u9879\u592a\u91cd \u56fe\u7247\u8d44\u6e90\u592a\u591a \u6eda\u52a8\u66f4\u65b0\u9891\u7e41 \u56e0\u6b64，\u865a\u62df\u5217\u8868\u6700\u6838\u5fc3\u7684\u672c\u8d28\u5c31\u662f：\u8ba9\u7528\u6237\u611f\u89c9\u81ea\u5df1\u5728\u6d4f\u89c8\u4e00\u4e2a\u5b8c\u6574\u7684\u8d85\u957f\u5217\u8868，\u4f46\u6d4f\u89c8\u5668\u5b9e\u9645\u4e0a\u53ea\u7ef4\u62a4\u5f53\u524d\u771f\u6b63\u9700\u8981\u7684\u5c11\u91cf DOM \u8282\u70b9\u3002<\/p>\n \u957f\u5217\u8868\u6700\u5927\u7684\u95ee\u9898\u662f\u5b9e\u9645\u6e32\u67d3\u8282\u70b9\u592a\u591a\u3002<\/p>\n \u6570\u636e\u5168\u91cf\u5b58\u5728，DOM \u6309\u9700\u6e32\u67d3\u3002<\/p>\n \u6839\u636e scrollTop \u548c\u5bb9\u5668\u9ad8\u5ea6\u8ba1\u7b97\u53ef\u89c6\u533a\u7d22\u5f15\u3002<\/p>\n \u8ba9\u6d4f\u89c8\u5668\u4ea7\u751f\u6b63\u786e\u7684\u6eda\u52a8\u6761\u3002<\/p>\n \u628a\u5c11\u91cf\u771f\u5b9e DOM \u653e\u5230\u5b8c\u6574\u5217\u8868\u5bf9\u5e94\u7684\u903b\u8f91\u4f4d\u7f6e\u3002<\/p>\n \u63d0\u524d\u6e32\u67d3\u4e0a\u4e0b\u5c11\u91cf\u8282\u70b9，\u907f\u514d\u5feb\u901f\u6eda\u52a8\u767d\u5c4f\u3002<\/p>\n \u9884\u4f30\u9ad8\u5ea6 + \u5b9e\u9645\u6d4b\u91cf + \u9ad8\u5ea6\u7f13\u5b58 + \u91cd\u65b0\u8ba1\u7b97\u4f4d\u7f6e\u3002<\/p>\n \u865a\u62df\u5217\u8868\u89e3\u51b3\u7684\u662f\u8282\u70b9\u6570\u91cf\u95ee\u9898，\u4e0d\u89e3\u51b3\u5355\u4e2a\u8282\u70b9\u8fc7\u91cd\u7684\u95ee\u9898，\u540c\u65f6\u8981\u8003\u8651\u52a8\u6001\u9ad8\u5ea6\u3001\u952e\u76d8\u5bfc\u822a\u3001\u7126\u70b9\u7ba1\u7406\u3001\u6d4f\u89c8\u5668\u67e5\u627e\u548c\u641c\u7d22\u5f15\u64ce\u4f18\u5316\u3002<\/p>\n \u865a\u62df\u5217\u8868 \u8fd9\u5c31\u662f React \u865a\u62df\u5217\u8868\u6700\u6838\u5fc3\u7684\u539f\u7406\u3002<\/p>\n","protected":false},"excerpt":{"rendered":" React \u865a\u62df\u5217\u8868\u9762\u8bd5\u9898\u6574\u7406
\n height<\/span>:<\/span> 600px;<\/span>
\n overflow<\/span>:<\/span> auto;<\/span>
\n}<\/span><\/p>\n
\n3. Virtual Content：\u865a\u62df\u5185\u5bb9\u533a\u57df<\/h5>\n
\n\u6bcf\u9879 50px<\/p>\n
\n= 5,000,000px<\/p>\n
\n <<\/span>div<\/span> class<\/span>=<\/span>"<\/span>virtual-content"<\/span><\/span>><\/span><\/span>
\n <!– \u53ea\u6e32\u67d3\u5f53\u524d\u53ef\u89c1\u7684\u51e0\u5341\u9879 –><\/span>
\n <\/<\/span>div<\/span>><\/span><\/span>
\n<\/<\/span>div<\/span>><\/span><\/span><\/p>\n
\n \u2193
\n\u8d1f\u8d23\u4ea7\u751f\u6eda\u52a8\u6761<\/p>\n
\n \u2193
\n\u8d1f\u8d23\u6491\u8d77\u5b8c\u6574\u5217\u8868\u7684\u6eda\u52a8\u7a7a\u95f4<\/p>\n
\n\u4e09\u3001\u9762\u8bd5\u9898：\u56fa\u5b9a\u9ad8\u5ea6\u865a\u62df\u5217\u8868\u662f\u600e\u4e48\u8ba1\u7b97\u53ef\u89c6\u533a\u57df\u7684？<\/h2>\n
\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）<\/h4>\n
\n\u8ba1\u7b97\u516c\u5f0f<\/h4>\n
\ncontainerHeight = 500px
\nscrollTop = 1250px<\/p>\n
\n = 35<\/p>\n
\n20<\/p>\n
\n40<\/p>\n
\n\u5b8c\u6574\u6d41\u7a0b<\/h4>\n
\n \u2193
\nscrollTop \u6539\u53d8
\n \u2193
\n\u8ba1\u7b97 startIndex
\n \u2193
\n\u8ba1\u7b97 endIndex
\n \u2193
\n\u589e\u52a0 overscan
\n \u2193
\n\u4ece\u5b8c\u6574\u6570\u636e\u4e2d\u5207\u7247
\n \u2193
\n\u6e32\u67d3\u8fd9\u4e00\u5c0f\u6bb5\u6570\u636e
\n \u2193
\n\u8ba1\u7b97\u6bcf\u4e00\u9879 top
\n \u2193
\n\u7edd\u5bf9\u5b9a\u4f4d<\/p>\n
\n\u56db\u3001\u9762\u8bd5\u9898：\u4e3a\u4ec0\u4e48\u865a\u62df\u5217\u8868\u9700\u8981\u201c\u603b\u9ad8\u5ea6\u5bb9\u5668\u201d？<\/h2>\n
\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）<\/h4>\n
\n\u4f8b\u5982<\/h4>\n
\n <<\/span>div<\/span> style<\/span>=<\/span>"<\/span>height<\/span>:<\/span> 500000px;<\/span> position<\/span>:<\/span> relative;<\/span><\/span>"<\/span><\/span><\/span>><\/span><\/span><\/p>\n
\n<\/<\/span>div<\/span>><\/span><\/span><\/p>\n
\n\u4e94\u3001\u9762\u8bd5\u9898：\u865a\u62df\u5217\u8868\u4e3a\u4ec0\u4e48\u901a\u5e38\u4f7f\u7528\u7edd\u5bf9\u5b9a\u4f4d？<\/h2>\n
\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）<\/h4>\n
\n\u67b6\u6784\u56fe<\/h4>\n
\n\u2502
\n\u251c\u2500\u2500 Item 0
\n\u2502
\n\u251c\u2500\u2500 Item 1
\n\u2502
\n\u251c\u2500\u2500 Item 2
\n\u2502
\n\u251c\u2500\u2500 …
\n\u2502
\n\u251c\u2500\u2500 Item 500
\n\u2502
\n\u2514\u2500\u2500 Item 99999<\/p>\n
\n\u2502
\n\u251c\u2500\u2500 Item 500 \u2192 top: 25000px
\n\u251c\u2500\u2500 Item 501 \u2192 top: 25050px
\n\u251c\u2500\u2500 Item 502 \u2192 top: 25100px
\n\u2514\u2500\u2500 Item 503 \u2192 top: 25150px<\/p>\n
\n position<\/span>:<\/span> absolute;<\/span>
\n left<\/span>:<\/span> 0;<\/span>
\n right<\/span>:<\/span> 0;<\/span>
\n}<\/span><\/p>\n
\n position: 'absolute',
\n top: index * itemHeight,
\n height: itemHeight,
\n}}<\/p>\n
\n\u516d\u3001\u9762\u8bd5\u9898：\u5982\u4f55\u624b\u5199\u4e00\u4e2a\u56fa\u5b9a\u9ad8\u5ea6\u7684 React \u865a\u62df\u5217\u8868？<\/h2>\n
\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）<\/h4>\n
\n\u5b8c\u6574\u793a\u4f8b\u4ee3\u7801<\/h4>\n
\n * \u4e00\u4e2a\u6700\u57fa\u7840\u7684\u56fa\u5b9a\u9ad8\u5ea6\u865a\u62df\u5217\u8868\u3002
\n *
\n * \u6838\u5fc3\u80fd\u529b：
\n * 1. \u53ea\u6e32\u67d3\u5f53\u524d\u53ef\u89c6\u533a\u57df\u9644\u8fd1\u7684\u5217\u8868\u9879
\n * 2. \u4f7f\u7528\u4e00\u4e2a\u603b\u9ad8\u5ea6\u5bb9\u5668\u6491\u8d77\u5b8c\u6574\u6eda\u52a8\u533a\u57df
\n * 3. \u4f7f\u7528\u7edd\u5bf9\u5b9a\u4f4d\u5c06\u5b9e\u9645\u6e32\u67d3\u7684\u8282\u70b9\u653e\u5230\u6b63\u786e\u4f4d\u7f6e
\n * 4. \u4f7f\u7528 requestAnimationFrame \u5408\u5e76\u9ad8\u9891\u6eda\u52a8\u66f4\u65b0
\n *\/
\nfunction VirtualList({
\n items,
\n height = 500,
\n itemHeight = 50,
\n overscan = 5,
\n}) {
\n \/**
\n * scrollTop \u8868\u793a\u5f53\u524d\u6eda\u52a8\u8ddd\u79bb\u3002
\n *
\n * \u6ce8\u610f：
\n * scroll \u4e8b\u4ef6\u89e6\u53d1\u9891\u7387\u53ef\u80fd\u975e\u5e38\u9ad8，
\n * \u56e0\u6b64\u8fd9\u91cc\u4e0d\u8981\u76f4\u63a5\u5728\u6bcf\u4e00\u6b21\u4e8b\u4ef6\u91cc\u505a\u5927\u91cf\u8ba1\u7b97\u3002
\n *\/
\n const [scrollTop, setScrollTop] = useState(0);<\/p>\n
\n * \u4f7f\u7528 requestAnimationFrame \u5408\u5e76\u540c\u4e00\u5e27\u5185\u7684\u591a\u6b21\u6eda\u52a8\u4e8b\u4ef6\u3002
\n *
\n * \u8fd9\u91cc\u6bd4\u7b80\u5355 debounce \u66f4\u9002\u5408\u6eda\u52a8\u573a\u666f：
\n *
\n * debounce \u4f1a\u7b49\u5f85\u6eda\u52a8\u505c\u6b62\u4ee5\u540e\u624d\u6267\u884c，
\n * \u7528\u6237\u5feb\u901f\u6eda\u52a8\u65f6\u53ef\u80fd\u5bfc\u81f4\u53ef\u89c6\u5185\u5bb9\u66f4\u65b0\u4e0d\u53ca\u65f6\u3002
\n *
\n * requestAnimationFrame \u66f4\u9002\u5408\u8ddf\u968f\u6d4f\u89c8\u5668\u7ed8\u5236\u8282\u594f\u66f4\u65b0 UI\u3002
\n *\/
\n const handleScroll = useCallback((event) => {
\n const currentScrollTop = event.currentTarget.scrollTop;<\/p>\n
\n setScrollTop(currentScrollTop);
\n });
\n }, []);<\/p>\n
\n * \u6839\u636e scrollTop \u8ba1\u7b97\u7406\u8bba\u53ef\u89c1\u533a\u57df\u3002
\n *\/
\n const { startIndex, endIndex } = useMemo(() => {
\n \/**
\n * \u5f53\u524d\u6eda\u52a8\u4f4d\u7f6e\u5bf9\u5e94\u7684\u7b2c\u4e00\u4e2a\u5217\u8868\u9879\u3002
\n *\/
\n const visibleStartIndex = Math.floor(
\n scrollTop \/ itemHeight
\n );<\/p>\n
\n * \u5bb9\u5668\u7406\u8bba\u4e0a\u80fd\u591f\u663e\u793a\u591a\u5c11\u9879\u3002
\n *
\n * \u4f7f\u7528 Math.ceil \u662f\u4e3a\u4e86\u907f\u514d\u6700\u540e\u4e00\u4e2a\u90e8\u5206\u53ef\u89c1\u7684\u5143\u7d20\u6ca1\u6709\u88ab\u8ba1\u7b97\u8fdb\u53bb\u3002
\n *\/
\n const visibleCount = Math.ceil(
\n height \/ itemHeight
\n );<\/p>\n
\n * \u5148\u8ba1\u7b97\u7406\u8bba\u7ed3\u675f\u4f4d\u7f6e\u3002
\n *\/
\n const visibleEndIndex =
\n visibleStartIndex + visibleCount;<\/p>\n
\n * \u5728\u53ef\u89c1\u533a\u57df\u4e0a\u4e0b\u589e\u52a0 overscan\u3002
\n *
\n * \u4f8b\u5982：
\n *
\n * \u53ef\u89c1\u533a\u57df：
\n * 100 ~ 110
\n *
\n * overscan = 5
\n *
\n * \u5b9e\u9645\u6e32\u67d3：
\n * 95 ~ 115
\n *
\n * \u8fd9\u6837\u5feb\u901f\u6eda\u52a8\u65f6\u4e0d\u5bb9\u6613\u51fa\u73b0\u767d\u5c4f\u3002
\n *\/
\n const start = Math.max(
\n 0,
\n visibleStartIndex – overscan
\n );<\/p>\n
\n items.length – 1,
\n visibleEndIndex + overscan
\n );<\/p>\n
\n startIndex: start,
\n endIndex: end,
\n };
\n }, [
\n scrollTop,
\n height,
\n itemHeight,
\n overscan,
\n items.length,
\n ]);<\/p>\n
\n * \u53ea\u622a\u53d6\u9700\u8981\u6e32\u67d3\u7684\u6570\u636e\u3002
\n *
\n * \u5982\u679c items \u6709 100000 \u6761，
\n * \u8fd9\u91cc\u53ef\u80fd\u53ea\u5f97\u5230 20～30 \u6761\u3002
\n *\/
\n const visibleItems = useMemo(() => {
\n return items.slice(
\n startIndex,
\n endIndex + 1
\n );
\n }, [
\n items,
\n startIndex,
\n endIndex,
\n ]);<\/p>\n
\n * \u6574\u4e2a\u5217\u8868\u7684\u903b\u8f91\u9ad8\u5ea6\u3002
\n *
\n * \u4f8b\u5982：
\n *
\n * 100000 \u6761 \u00d7 50px
\n * = 5000000px
\n *
\n * \u8fd9\u4e2a\u9ad8\u5ea6\u5e76\u4e0d\u610f\u5473\u7740\u771f\u7684\u521b\u5efa\u4e86 5000000px \u7684 DOM \u5185\u5bb9，
\n * \u5b83\u53ea\u662f\u7528\u4e8e\u544a\u8bc9\u6d4f\u89c8\u5668：
\n *
\n * \u201c\u6574\u4e2a\u5217\u8868\u7406\u8bba\u4e0a\u6709\u8fd9\u4e48\u957f\u3002\u201d
\n *\/
\n const totalHeight =
\n items.length * itemHeight;<\/p>\n
\n <div
\n \/**
\n * \u5916\u5c42\u6eda\u52a8\u5bb9\u5668\u3002
\n *\/
\n style={{
\n height,
\n overflowY: 'auto',
\n position: 'relative',
\n border: '1px solid #ddd',
\n }}
\n onScroll={handleScroll}
\n >
\n <div
\n \/**
\n * \u5185\u5c42\u5bb9\u5668\u8d1f\u8d23\u6491\u8d77\u5b8c\u6574\u6eda\u52a8\u9ad8\u5ea6\u3002
\n *\/
\n style={{
\n position: 'relative',
\n height: totalHeight,
\n }}
\n >
\n {visibleItems.map((item, offset) => {
\n \/**
\n * visibleItems \u662f\u4ece startIndex \u5f00\u59cb\u622a\u53d6\u7684，
\n * \u6240\u4ee5\u771f\u5b9e index：
\n *
\n * startIndex + offset
\n *\/
\n const index =
\n startIndex + offset;<\/p>\n
\n <div
\n \/**
\n * key \u5fc5\u987b\u5c3d\u53ef\u80fd\u4f7f\u7528\u7a33\u5b9a\u7684\u4e1a\u52a1 ID，
\n * \u4e0d\u5efa\u8bae\u5728\u6570\u636e\u53ef\u53d8\u7684\u60c5\u51b5\u4e0b\u4f7f\u7528 index\u3002
\n *
\n * \u8fd9\u91cc\u5047\u8bbe item.id \u662f\u7a33\u5b9a\u552f\u4e00 ID\u3002
\n *\/
\n key={item.id}
\n style={{
\n position: 'absolute',<\/p>\n
\n * \u6839\u636e\u771f\u5b9e index \u8ba1\u7b97\u5143\u7d20\u5728\u5b8c\u6574\u5217\u8868\u4e2d\u7684\u4f4d\u7f6e\u3002
\n *\/
\n top:
\n index * itemHeight,<\/p>\n
\n right: 0,<\/p>\n
\n * \u56fa\u5b9a\u9ad8\u5ea6\u5217\u8868\u3002
\n *\/
\n height: itemHeight,<\/p>\n
\n * \u793a\u4f8b\u6837\u5f0f\u3002
\n *\/
\n boxSizing: 'border-box',
\n padding: '0 16px',
\n display: 'flex',
\n alignItems: 'center',
\n borderBottom:
\n '1px solid #eee',
\n }}
\n >
\n \u7b2c {index + 1} \u9879：{item.name}
\n <\/div>
\n );
\n })}
\n <\/div>
\n <\/div>
\n );
\n}<\/p>\n
\n * \u793a\u4f8b\u9875\u9762\u3002
\n *\/
\nexport default function App() {
\n \/**
\n * \u6a21\u62df 100000 \u6761\u6570\u636e\u3002
\n *
\n * \u6ce8\u610f：
\n * \u865a\u62df\u5217\u8868\u89e3\u51b3\u7684\u662f\u201c\u6e32\u67d3\u6027\u80fd\u201d\u95ee\u9898，
\n * \u5e76\u4e0d\u610f\u5473\u7740\u4e00\u6b21\u6027\u521b\u5efa 100000 \u6761 JavaScript \u6570\u636e
\n * \u5c31\u5b8c\u5168\u6ca1\u6709\u6210\u672c\u3002
\n *\/
\n const items = useMemo(() => {
\n return Array.from(
\n { length: 100000 },
\n (_, index) => ({
\n id: `item-${index}`,
\n name: `\u5546\u54c1 ${index + 1}`,
\n })
\n );
\n }, []);<\/p>\n
\n <div>
\n <h2>React \u56fa\u5b9a\u9ad8\u5ea6\u865a\u62df\u5217\u8868<\/h2><\/p>\n
\n items={items}
\n height={500}
\n itemHeight={50}
\n overscan={5}
\n \/>
\n <\/div>
\n );
\n}<\/p>\n
\n\u8fd9\u6bb5\u4ee3\u7801\u6700\u6838\u5fc3\u7684\u5730\u65b9\u53ea\u6709\u56db\u6b65<\/h4>\n
\n \u2193
\n2. startIndex \/ endIndex
\n \u2193
\n3. items.slice(startIndex, endIndex)
\n \u2193
\n4. position: absolute + top<\/p>\n
\n\u4e03\u3001\u9762\u8bd5\u9898：\u865a\u62df\u5217\u8868\u7684 overscan \u662f\u4ec0\u4e48？\u4e3a\u4ec0\u4e48\u9700\u8981\u5b83？<\/h2>\n
\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）<\/h4>\n
\n\u793a\u4f8b<\/h4>\n
\n \u2193 \u2193<\/p>\n
\n———————
\n100 101 102 … 110 \u2190 \u53ef\u89c6\u533a\u57df
\n———————
\n111 112 113 114 115
\n \u2191 \u2191
\n overscan<\/p>\n
\noverscan \u592a\u5c0f<\/h4>\n
\n\u2193
\n\u5185\u5b58\u66f4\u4f4e
\n\u2193
\n\u4f46\u662f\u5feb\u901f\u6eda\u52a8\u65f6
\n\u2193
\n\u5bb9\u6613\u6765\u4e0d\u53ca\u6e32\u67d3
\n\u2193
\n\u51fa\u73b0\u767d\u5c4f<\/p>\noverscan \u592a\u5927<\/h4>\n
\n\u2193
\n\u4f46\u662f\u5b9e\u9645 DOM \u589e\u591a
\n\u2193
\n\u865a\u62df\u5316\u6536\u76ca\u4e0b\u964d<\/p>\n
\n\u516b\u3001\u9762\u8bd5\u9898：\u865a\u62df\u5217\u8868\u662f\u600e\u4e48\u505a\u5230\u201c\u6570\u636e 10 \u4e07\u6761\u4f46 DOM \u53ea\u6709\u51e0\u5341\u4e2a\u201d\u7684？<\/h2>\n
\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）<\/h4>\n
\n\u666e\u901a\u5217\u8868<\/h4>\n
\n100000<\/p>\n
\n\u2248 100000<\/p>\n\u865a\u62df\u5217\u8868<\/h4>\n
\n100000<\/p>\n
\n\u2248 viewport \/ itemHeight + overscan<\/p>\n
\nitem \u9ad8\u5ea6：50px
\noverscan：5<\/p>\n
\n12<\/p>\n
\n12 + 5 + 5<\/p>\n
\n\u4e5d\u3001\u9762\u8bd5\u9898：\u865a\u62df\u5217\u8868\u6709\u54ea\u4e9b\u6027\u80fd\u6536\u76ca？<\/h2>\n
\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）<\/h4>\n
\n\u4e3b\u8981\u6536\u76ca<\/h4>\n
1. \u964d\u4f4e DOM \u6570\u91cf<\/h5>\n
\n2. \u964d\u4f4e\u521d\u59cb\u6e32\u67d3\u6210\u672c<\/h5>\n
\n3. \u964d\u4f4e\u5185\u5b58\u5360\u7528<\/h5>\n
\n4. \u964d\u4f4e\u6d4f\u89c8\u5668\u5e03\u5c40\u548c\u7ed8\u5236\u6210\u672c<\/h5>\n
\n5. \u964d\u4f4e\u5217\u8868\u66f4\u65b0\u6210\u672c<\/h5>\n
\n\u4f46\u6709\u4e00\u4e2a\u91cd\u8981\u7ea0\u6b63<\/h4>\n
\n\u5341\u3001\u9762\u8bd5\u9898：React \u865a\u62df\u5217\u8868\u5e94\u8be5\u5982\u4f55\u5904\u7406\u6eda\u52a8\u4e8b\u4ef6？<\/h2>\n
\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）<\/h4>\n
\n\u4e0d\u63a8\u8350\u7b80\u5355 debounce<\/h4>\n
\n\u2193
\ndebounce \u4e00\u76f4\u7b49\u5f85
\n\u2193
\n\u53ef\u89c6\u533a\u57df\u66f4\u65b0\u4e0d\u53ca\u65f6
\n\u2193
\n\u5bb9\u6613\u51fa\u73b0\u767d\u5c4f<\/p>\n
\n \u2193
\nrequestAnimationFrame
\n \u2193
\n\u6bcf\u4e00\u5e27\u6700\u591a\u66f4\u65b0\u4e00\u6b21
\n \u2193
\n\u8ba1\u7b97\u53ef\u89c6\u533a\u57df
\n \u2193
\n\u66f4\u65b0\u6e32\u67d3\u7a97\u53e3<\/p>\n
\n\u63a8\u8350\u6d41\u7a0b<\/h4>\n
\n \u2193
\n\u8bfb\u53d6 scrollTop
\n \u2193
\nrequestAnimationFrame
\n \u2193
\n\u8ba1\u7b97 startIndex \/ endIndex
\n \u2193
\n\u66f4\u65b0\u6e32\u67d3\u8303\u56f4
\n \u2193
\nReact \u66f4\u65b0<\/p>\n
\n\u5341\u4e00\u3001\u9762\u8bd5\u9898：\u52a8\u6001\u9ad8\u5ea6\u5217\u8868\u600e\u4e48\u5b9e\u73b0\u865a\u62df\u5316？<\/h2>\n
\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）<\/h4>\n
\n\u56fa\u5b9a\u9ad8\u5ea6<\/h4>\n
\n \u2193
\nindex \u00d7 itemHeight
\n \u2193
\ntop<\/p>\n
\n = 5000px<\/p>\n
\n\u52a8\u6001\u9ad8\u5ea6<\/h4>\n
\nItem 1 = 80px
\nItem 2 = 120px
\nItem 3 = 60px<\/p>\n
\ntop = 0<\/p>\n
\ntop = 50<\/p>\n
\ntop = 50 + 80
\n = 130<\/p>\n
\ntop = 50 + 80 + 120
\n = 250<\/p>\n
\n\u52a8\u6001\u9ad8\u5ea6\u67b6\u6784<\/h4>\n
\n \u2193
\n\u9884\u4f30\u9ad8\u5ea6
\n \u2193
\n\u9996\u6b21\u6e32\u67d3
\n \u2193
\nDOM \u5b9e\u9645\u6e32\u67d3
\n \u2193
\nResizeObserver \/ DOM \u6d4b\u91cf
\n \u2193
\n\u83b7\u5f97\u771f\u5b9e\u9ad8\u5ea6
\n \u2193
\n\u66f4\u65b0 heightCache
\n \u2193
\n\u91cd\u65b0\u8ba1\u7b97 prefix sum
\n \u2193
\n\u91cd\u65b0\u8ba1\u7b97\u5217\u8868\u9879\u4f4d\u7f6e
\n \u2193
\n\u91cd\u65b0\u8ba1\u7b97\u603b\u9ad8\u5ea6
\n \u2193
\n\u66f4\u65b0\u865a\u62df\u5217\u8868<\/p>\n
\n\u9ad8\u5ea6\u7f13\u5b58<\/h4>\n
\nheightCache.<\/span>set<\/span>(<\/span>1<\/span>,<\/span> 80<\/span>)<\/span>;<\/span>
\nheightCache.<\/span>set<\/span>(<\/span>2<\/span>,<\/span> 120<\/span>)<\/span>;<\/span><\/p>\n
\n \u2193
\n\u8ba1\u7b97\u6bcf\u4e2a item \u7684 top
\n \u2193
\n\u8ba1\u7b97\u603b\u9ad8\u5ea6<\/p>\n
\n\u5341\u4e8c\u3001\u9762\u8bd5\u9898：\u4e3a\u4ec0\u4e48\u52a8\u6001\u9ad8\u5ea6\u865a\u62df\u5217\u8868\u6bd4\u56fa\u5b9a\u9ad8\u5ea6\u590d\u6742\u5f88\u591a？<\/h2>\n
\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）<\/h4>\n
\n\u56fa\u5b9a\u9ad8\u5ea6<\/h4>\n
\n\u52a8\u6001\u9ad8\u5ea6<\/h4>\n
\n+ height[1]
\n+ height[2]
\n+ …
\n+ height[n]<\/p>\n
\n\u4e8c\u5206\u67e5\u627e
\n\u9ad8\u5ea6\u7f13\u5b58
\n\u52a8\u6001\u6d4b\u91cf
\n\u4f4d\u7f6e\u4fee\u6b63<\/p>\n
\n\u66f4\u8fdb\u4e00\u6b65\u7684\u4f18\u5316<\/h4>\n
\n \u2193
\n\u4e8c\u5206\u67e5\u627e scrollTop \u5bf9\u5e94\u7684 index<\/p>\n
\n\u5341\u4e09\u3001\u9762\u8bd5\u9898：\u52a8\u6001\u9ad8\u5ea6\u5217\u8868\u7b2c\u4e00\u6b21\u6e32\u67d3\u65f6\u9ad8\u5ea6\u4e0d\u77e5\u9053\u600e\u4e48\u529e？<\/h2>\n
\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）<\/h4>\n
\n\u6d41\u7a0b<\/h4>\n
\n \u2193
\nestimatedHeight
\n \u2193
\n\u5efa\u7acb\u521d\u59cb\u865a\u62df\u5e03\u5c40
\n \u2193
\n\u6e32\u67d3
\n \u2193
\n\u6d4b\u91cf\u771f\u5b9e\u9ad8\u5ea6
\n \u2193
\n\u66f4\u65b0 heightCache
\n \u2193
\n\u91cd\u65b0\u8ba1\u7b97\u4f4d\u7f6e
\n \u2193
\n\u91cd\u65b0\u8ba1\u7b97\u603b\u9ad8\u5ea6<\/p>\n
\n\u5e38\u89c1\u6d4b\u91cf\u65b9\u6848<\/h4>\n
\n for<\/span> (<\/span>const<\/span> entry of<\/span> entries)<\/span> {<\/span>
\n const<\/span> height =<\/span> entry.<\/span>contentRect.<\/span>height;<\/span><\/p>\n
\n \/\/ \u7136\u540e\u89e6\u53d1\u5e03\u5c40\u91cd\u65b0\u8ba1\u7b97<\/span>
\n }<\/span>
\n}<\/span>)<\/span>;<\/span><\/p>\n
\n\u5341\u56db\u3001\u9762\u8bd5\u9898：React \u865a\u62df\u5217\u8868\u4f7f\u7528\u7b2c\u4e09\u65b9\u5e93\u8fd8\u662f\u81ea\u5df1\u5b9e\u73b0？<\/h2>\n
\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）<\/h4>\n
\n\u81ea\u5df1\u5b9e\u73b0<\/h4>\n
\n\u2193
\n\u53ef\u4ee5\u9488\u5bf9\u4e1a\u52a1\u5b9a\u5236
\n\u2193
\n\u53ef\u4ee5\u6df1\u5165\u7406\u89e3\u539f\u7406<\/p>\n
\n\u2193
\n\u52a8\u6001\u9ad8\u5ea6
\n\u2193
\n\u6a2a\u5411\u6eda\u52a8
\n\u2193
\n\u952e\u76d8\u5bfc\u822a
\n\u2193
\n\u7126\u70b9\u7ba1\u7406
\n\u2193
\noverscan
\n\u2193
\n\u6eda\u52a8\u4f4d\u7f6e\u6062\u590d
\n\u2193
\nResizeObserver
\n\u2193
\n\u6570\u636e\u53d8\u5316
\n\u2193
\n\u63d2\u5165 \/ \u5220\u9664
\n\u2193
\n\u951a\u70b9\u5b9a\u4f4d
\n\u2193
\n\u6d4f\u89c8\u5668\u517c\u5bb9<\/p>\n
\n\u56e0\u6b64\u751f\u4ea7\u73af\u5883\u901a\u5e38\u8003\u8651\u6210\u719f\u65b9\u6848<\/h4>\n
\n
\n\u5341\u4e94\u3001\u9762\u8bd5\u9898：React Window \u7684\u56fa\u5b9a\u9ad8\u5ea6\u5217\u8868\u600e\u4e48\u4f7f\u7528？<\/h2>\n
\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）<\/h4>\n
\n height={500}
\n itemCount={100000}
\n itemSize={50}
\n width="100%"
\n>
\n {Row}
\n<\/FixedSizeList><\/p>\n
\n\u4ee3\u7801\u793a\u4f8b<\/h4>\n
\nimport { FixedSizeList } from 'react-window';<\/p>\n
\n * \u5217\u8868\u884c\u7ec4\u4ef6\u3002
\n *
\n * React Window \u4f1a\u628a\u5f53\u524d\u9700\u8981\u6e32\u67d3\u7684\u884c\u5bf9\u5e94\u7684\u53c2\u6570\u4f20\u9012\u7ed9\u8fd9\u91cc\u3002
\n *\/
\nfunction Row({ index, style }) {
\n return (
\n <div
\n \/**
\n * \u6ce8\u610f：
\n * style \u662f\u865a\u62df\u5217\u8868\u5e93\u8ba1\u7b97\u597d\u7684\u5b9a\u4f4d\u6837\u5f0f\u3002
\n *
\n * \u4e0d\u5e94\u8be5\u968f\u610f\u8986\u76d6\u5176\u4e2d\u7684 top\u3001height\u3001position \u7b49\u5173\u952e\u5c5e\u6027\u3002
\n *\/
\n style={{
\n …style,<\/p>\n
\n * \u8fd9\u91cc\u53ea\u6dfb\u52a0\u4e1a\u52a1\u81ea\u5df1\u7684\u89c6\u89c9\u6837\u5f0f\u3002
\n *\/
\n display: 'flex',
\n alignItems: 'center',
\n padding: '0 16px',
\n borderBottom: '1px solid #eee',
\n boxSizing: 'border-box',
\n }}
\n >
\n \u7b2c {index + 1} \u9879
\n <\/div>
\n );
\n}<\/p>\n
\n \/**
\n * \u6a21\u62df\u5927\u91cf\u6570\u636e\u3002
\n *
\n * \u771f\u6b63\u4e1a\u52a1\u4e2d\u901a\u5e38\u4f1a\u4ece\u63a5\u53e3\u83b7\u53d6\u6570\u636e\u3002
\n *\/
\n const items = useMemo(() => {
\n return Array.from(
\n { length: 100000 },
\n (_, index) => ({
\n id: index,
\n name: `\u5546\u54c1 ${index + 1}`,
\n })
\n );
\n }, []);<\/p>\n
\n <FixedSizeList
\n \/**
\n * \u865a\u62df\u5217\u8868\u53ef\u89c6\u533a\u57df\u9ad8\u5ea6\u3002
\n *\/
\n height={500}<\/p>\n
\n * \u5217\u8868\u603b\u6570\u636e\u91cf\u3002
\n *\/
\n itemCount={items.length}<\/p>\n
\n * \u6bcf\u4e00\u9879\u56fa\u5b9a\u9ad8\u5ea6\u3002
\n *\/
\n itemSize={50}<\/p>\n
\n * \u5bbd\u5ea6\u53ef\u4ee5\u6839\u636e\u4e1a\u52a1\u8c03\u6574\u3002
\n *\/
\n width="100%"
\n >
\n {Row}
\n <\/FixedSizeList>
\n );
\n}<\/p>\n
\n\u5341\u516d\u3001\u9762\u8bd5\u9898：\u53ef\u53d8\u9ad8\u5ea6\u548c\u56fa\u5b9a\u9ad8\u5ea6\u5e94\u8be5\u600e\u4e48\u9009\u62e9？<\/h2>\n
\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）<\/h4>\n
\n\u56fa\u5b9a\u9ad8\u5ea6<\/h4>\n
\n\u7528\u6237\u5217\u8868
\n\u7b80\u5355\u6d88\u606f\u5217\u8868
\n\u540e\u53f0\u6570\u636e\u8868\u683c
\n\u65e5\u5fd7\u5217\u8868<\/p>\n
\n\u52a8\u6001\u9ad8\u5ea6<\/h4>\n
\n\u5bcc\u6587\u672c
\n\u5c55\u5f00\/\u6536\u8d77\u5185\u5bb9
\n\u4e0d\u540c\u957f\u5ea6\u7684\u5361\u7247
\n\u8bc4\u8bba
\n\u6587\u7ae0\u5217\u8868<\/p>\n
\n\u5341\u4e03\u3001\u9762\u8bd5\u9898：\u865a\u62df\u5217\u8868\u6709\u4ec0\u4e48\u7f3a\u70b9\u548c\u9650\u5236？<\/h2>\n
\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）<\/h4>\n
\n1. \u52a8\u6001\u9ad8\u5ea6\u590d\u6742<\/h4>\n
\n\u2193
\n\u7f13\u5b58
\n\u2193
\n\u91cd\u65b0\u8ba1\u7b97\u4f4d\u7f6e
\n\u2193
\n\u5904\u7406\u6eda\u52a8\u4f4d\u7f6e\u4fee\u6b63<\/p>\n
\n2. \u5feb\u901f\u6eda\u52a8\u53ef\u80fd\u51fa\u73b0\u767d\u5c4f<\/h4>\n
\n\u2193
\nscrollTop \u7a81\u7136\u8df3\u8dc3\u51e0\u5343\u50cf\u7d20
\n\u2193
\n\u9700\u8981\u7acb\u5373\u8ba1\u7b97\u65b0\u533a\u57df
\n\u2193
\n\u65b0\u8282\u70b9\u8fd8\u6ca1\u6709\u5b8c\u6210\u6e32\u67d3
\n\u2193
\n\u77ed\u6682\u767d\u5c4f<\/p>\n
\n+
\n\u51cf\u5c11\u5355\u9879\u6e32\u67d3\u6210\u672c
\n+
\n\u5408\u7406\u63a7\u5236\u6eda\u52a8\u66f4\u65b0<\/p>\n
\n3. \u5217\u8868\u9879\u672c\u8eab\u5f88\u91cd\u65f6，\u865a\u62df\u5217\u8868\u4ecd\u7136\u53ef\u80fd\u5361<\/h4>\n
\n <\u590d\u6742\u56fe\u8868 \/>
\n <\u590d\u6742\u5bcc\u6587\u672c \/>
\n <\u5927\u91cf\u8ba1\u7b97 \/>
\n <\u591a\u4e2a\u56fe\u7247 \/>
\n<\/Item><\/p>\n
\n4. \u952e\u76d8\u5bfc\u822a\u66f4\u52a0\u590d\u6742<\/h4>\n
\n\u2191
\n\u2193
\nHome
\nEnd
\nPageUp
\nPageDown<\/p>\n
\n+
\nfocus management
\n+
\nscrollToItem<\/p>\n
\n5. \u6d4f\u89c8\u5668\u67e5\u627e\u529f\u80fd\u4f53\u9a8c\u53ef\u80fd\u53d7\u5f71\u54cd<\/h4>\n
\n\u2193
\n\u5f97\u5230 index
\n\u2193
\nscrollToIndex(index)
\n\u2193
\n\u6302\u8f7d\u76ee\u6807\u8282\u70b9<\/p>\n
\n6. SEO \u9700\u8981\u8c28\u614e<\/h4>\n
\n+
\n\u9884\u6e32\u67d3
\n+
\n\u7ed3\u6784\u5316\u6570\u636e
\n+
\n\u5408\u7406\u5206\u9875
\n+
\n\u53ef\u8bbf\u95ee\u7684 URL<\/p>\n
\n\u5341\u516b\u3001\u9762\u8bd5\u9898：\u865a\u62df\u5217\u8868\u548c\u5206\u9875\u3001\u65e0\u9650\u6eda\u52a8\u6709\u4ec0\u4e48\u533a\u522b？<\/h2>\n
\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）<\/h4>\n
\n\u5206\u9875<\/h4>\n
\n \u2193
\n\u53ea\u83b7\u53d6\u7b2c 1 \u9875
\n \u2193
\n20 \u6761
\n \u2193
\n\u7528\u6237\u70b9\u51fb\u4e0b\u4e00\u9875
\n \u2193
\n\u518d\u83b7\u53d6 20 \u6761<\/p>\n
\n\u6570\u636e\u83b7\u53d6
\n\u670d\u52a1\u5668\u538b\u529b<\/p>\n
\n\u865a\u62df\u5217\u8868<\/h4>\n
\n \u2193
\n\u53ea\u6e32\u67d3\u5f53\u524d 20～50 \u6761<\/p>\n
\nReact \u6e32\u67d3
\n\u6d4f\u89c8\u5668\u5e03\u5c40\u7ed8\u5236<\/p>\n
\n\u65e0\u9650\u6eda\u52a8<\/h4>\n
\n \u2193
\n\u8bf7\u6c42\u4e0b\u4e00\u6279\u6570\u636e
\n \u2193
\n\u8ffd\u52a0\u6570\u636e<\/p>\n
\n\u4e09\u8005\u53ef\u4ee5\u7ec4\u5408<\/h4>\n
\n \u2193
\n\u5ba2\u6237\u7aef\u6301\u7eed\u52a0\u8f7d
\n \u2193
\n\u7d2f\u8ba1 100000 \u6761
\n \u2193
\n\u865a\u62df\u5217\u8868
\n \u2193
\n\u53ea\u6e32\u67d3\u5f53\u524d 30 \u6761<\/p>\n
\n\u5341\u4e5d\u3001\u9762\u8bd5\u9898：\u865a\u62df\u5217\u8868\u662f\u4e0d\u662f\u6570\u636e\u91cf\u8d85\u8fc7 1000 \u6761\u5c31\u4e00\u5b9a\u8981\u7528？<\/h2>\n
\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）<\/h4>\n
\n\u4e0d\u5e94\u8be5\u6b7b\u8bb0：<\/h4>\n
\n\u8d85\u8fc7 10000 \u2192 \u865a\u62df\u5217\u8868<\/p>\n
\n \u2193
\nDOM \u8282\u70b9\u6709\u591a\u5c11？
\n \u2193
\n\u662f\u5426\u9891\u7e41\u66f4\u65b0？
\n \u2193
\n\u662f\u5426\u9700\u8981\u6d41\u7545\u6eda\u52a8？
\n \u2193
\n\u662f\u5426\u52a8\u6001\u9ad8\u5ea6？
\n \u2193
\n\u662f\u5426\u5b58\u5728 SEO？
\n \u2193
\n\u662f\u5426\u9700\u8981\u952e\u76d8\u5bfc\u822a？
\n \u2193
\n\u5b9e\u9645\u6027\u80fd\u6307\u6807\u5982\u4f55？<\/p>\n
\n+ \u56fe\u7247
\n+ \u56fe\u8868
\n+ \u5bcc\u6587\u672c
\n+ \u591a\u5c42\u7ec4\u4ef6<\/p>\n
\n\u4e8c\u5341\u3001\u9762\u8bd5\u9898：\u865a\u62df\u5217\u8868\u548c React.memo \u80fd\u4e0d\u80fd\u4e00\u8d77\u4f7f\u7528？<\/h2>\n
\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）<\/h4>\n
\n\u4e24\u8005\u5173\u7cfb<\/h4>\n
\n\u2193
\n\u51cf\u5c11\u8282\u70b9\u6570\u91cf<\/p>\n
\n\u2193
\n\u51cf\u5c11\u4e0d\u5fc5\u8981\u7684\u7ec4\u4ef6\u91cd\u65b0\u6e32\u67d3<\/p>\n
\n\u2193
\n\u865a\u62df\u5217\u8868
\n\u2193
\n\u5b9e\u9645 30 \u6761
\n\u2193
\nReact.memo
\n\u2193
\n\u8fd9 30 \u6761\u4e2d\u53ea\u6709\u771f\u6b63\u53d1\u751f\u53d8\u5316\u7684\u624d\u91cd\u65b0\u6e32\u67d3<\/p>\n
\n\u4f46\u4e0d\u8981\u6ee5\u7528<\/h4>\n
\n\u4e8c\u5341\u4e00\u3001\u9762\u8bd5\u9898：\u865a\u62df\u5217\u8868\u548c React \u5e76\u53d1\u6e32\u67d3\u662f\u4ec0\u4e48\u5173\u7cfb？<\/h2>\n
\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）<\/h4>\n
\n\u865a\u62df\u5217\u8868<\/h4>\n
\n\u2193
\n30 DOM<\/p>\n
\nReact \u5e76\u53d1\u6e32\u67d3<\/h4>\n
\n+
\n\u4f4e\u4f18\u5148\u7ea7\u5217\u8868\u66f4\u65b0<\/p>\n
\n\u6240\u4ee5：<\/h4>\n
\n= \u51cf\u5c11\u5de5\u4f5c\u91cf<\/p>\n
\n= \u8c03\u5ea6\u5de5\u4f5c\u91cf<\/p>\n
\n= \u51cf\u5c11\u91cd\u590d\u5de5\u4f5c<\/p>\n
\n= \u914d\u5408\u6d4f\u89c8\u5668\u7ed8\u5236\u8282\u594f<\/p>\n
\n= \u51cf\u5c11\u6570\u636e\u83b7\u53d6\u91cf<\/p>\n
\n\u4e8c\u5341\u4e8c\u3001\u9762\u8bd5\u9898：\u865a\u62df\u5217\u8868\u6700\u6838\u5fc3\u7684\u5b9e\u73b0\u539f\u7406\u53ef\u4ee5\u6982\u62ec\u6210\u4ec0\u4e48？<\/h2>\n
\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）<\/h4>\n
\n\u6838\u5fc3\u67b6\u6784\u56fe<\/h4>\n
\n \u2502
\n \u2193
\n \u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510
\n \u2502 Virtual List \u2502
\n \u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518
\n \u2502
\n \u250c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2510
\n \u2193 \u2193 \u2193
\n scrollTop containerHeight itemHeight
\n \u2502 \u2502 \u2502
\n \u2514\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u253c\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2500\u2518
\n \u2193
\n \u8ba1\u7b97\u53ef\u89c6\u7d22\u5f15
\n \u2193
\n startIndex \/ endIndex
\n \u2193
\n overscan
\n \u2193
\n slice \u6570\u636e
\n \u2193
\n \u6e32\u67d3\u5c11\u91cf\u5217\u8868\u9879
\n \u2193
\n absolute + top
\n \u2193
\n \u653e\u5230\u6b63\u786e\u7684\u4f4d\u7f6e
\n \u2193
\n \u7528\u6237\u770b\u5230\u5b8c\u6574\u5217\u8868<\/p>\n
\n\u4e8c\u5341\u4e09\u3001\u9762\u8bd5\u9898：\u5982\u679c\u8ba9\u4f60\u4ece\u96f6\u5b9e\u73b0\u4e00\u4e2a\u865a\u62df\u5217\u8868，\u4f60\u4f1a\u600e\u4e48\u8bbe\u8ba1？<\/h2>\n
\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）<\/h4>\n
\n\u7b2c\u4e00\u9636\u6bb5：\u56fa\u5b9a\u9ad8\u5ea6<\/h4>\n
\n\u2193
\nstartIndex
\n\u2193
\nendIndex
\n\u2193
\nslice
\n\u2193
\nabsolute positioning<\/p>\n
\n\u7b2c\u4e8c\u9636\u6bb5：overscan<\/h4>\n
\n\u2193
\n\u6269\u5927\u4e0a\u4e0b\u8303\u56f4
\n\u2193
\n\u51cf\u5c11\u5feb\u901f\u6eda\u52a8\u767d\u5c4f<\/p>\n
\n\u7b2c\u4e09\u9636\u6bb5：\u52a8\u6001\u9ad8\u5ea6<\/h4>\n
\nheightCache
\nResizeObserver
\nprefix sum
\nbinary search<\/p>\n
\n\u7b2c\u56db\u9636\u6bb5：\u590d\u6742\u4ea4\u4e92<\/h4>\n
\n\u5220\u9664
\n\u6392\u5e8f
\n\u7b5b\u9009
\n\u641c\u7d22\u5b9a\u4f4d
\n\u6eda\u52a8\u5230\u6307\u5b9a index
\n\u952e\u76d8\u5bfc\u822a
\n\u7126\u70b9\u7ba1\u7406<\/p>\n
\n\u7b2c\u4e94\u9636\u6bb5：\u5de5\u7a0b\u4f18\u5316<\/h4>\n
\nReact.memo
\n\u7a33\u5b9a key
\n\u56fe\u7247\u61d2\u52a0\u8f7d
\n\u7ec4\u4ef6\u62c6\u5206
\n\u9519\u8bef\u8fb9\u754c
\n\u6027\u80fd\u76d1\u63a7<\/p>\n
\n\u4e8c\u5341\u56db\u3001\u9762\u8bd5\u9898：\u865a\u62df\u5217\u8868\u5b9e\u73b0\u4e2d\u6709\u54ea\u4e9b\u5bb9\u6613\u8e29\u5751\u7684\u5730\u65b9？<\/h2>\n
1. \u4f7f\u7528 index \u4f5c\u4e3a key<\/h4>\n
\n <Item key={index} \/>
\n))<\/p>\n
\n\u5220\u9664
\n\u6392\u5e8f
\n\u7b5b\u9009<\/p>\n
\n2. scroll \u4e8b\u4ef6\u4e2d\u505a\u5927\u91cf\u8ba1\u7b97<\/h4>\n
\n \/\/ \u5927\u91cf\u8ba1\u7b97<\/span>
\n \/\/ \u5927\u91cf setState<\/span>
\n \/\/ \u5927\u91cf DOM \u64cd\u4f5c<\/span>
\n}<\/span>}<\/span><\/p>\n
\n\u2193
\n\u8f7b\u91cf\u8bfb\u53d6 scrollTop
\n\u2193
\nrequestAnimationFrame
\n\u2193
\n\u7edf\u4e00\u8ba1\u7b97<\/p>\n
\n3. overscan \u592a\u5c0f<\/h4>\n
\n\u2193
\n\u767d\u5c4f<\/p>\n
\n4. overscan \u592a\u5927<\/h4>\n
\n\u2193
\n\u865a\u62df\u5217\u8868\u6536\u76ca\u4e0b\u964d<\/p>\n
\n5. \u52a8\u6001\u9ad8\u5ea6\u5bfc\u81f4\u6eda\u52a8\u8df3\u52a8<\/h4>\n
\n\u771f\u5b9e\u9ad8\u5ea6：300px<\/p>\n
\n6. \u5217\u8868\u9879\u5185\u90e8\u6709\u6602\u8d35\u8ba1\u7b97<\/h4>\n
\n <HugeChart \/>
\n <RichText \/>
\n <ComplexCalculation \/>
\n<\/Item><\/p>\n
\nuseMemo
\n\u6570\u636e\u9884\u8ba1\u7b97
\n\u56fe\u7247\u61d2\u52a0\u8f7d
\n\u62c6\u5206\u7ec4\u4ef6<\/p>\n
\n7. \u5ffd\u7565\u53ef\u8bbf\u95ee\u6027<\/h4>\n
\naria \u5c5e\u6027
\n\u7126\u70b9\u7ba1\u7406
\n\u5f53\u524d\u6d3b\u52a8\u9879
\n\u5c4f\u5e55\u9605\u8bfb\u5668<\/p>\n
\n\u4e8c\u5341\u4e94\u3001\u9762\u8bd5\u9898：\u865a\u62df\u5217\u8868\u3001\u61d2\u52a0\u8f7d\u548c\u5206\u9875\u662f\u4e0d\u662f\u4e00\u56de\u4e8b？<\/h2>\n
\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）<\/h4>\n
\n\u4e09\u8005\u5bf9\u6bd4<\/h4>\n
\n
\u6280\u672f\u4e3b\u8981\u89e3\u51b3\u7684\u95ee\u9898\u4f18\u5316\u5bf9\u8c61<\/tr>\n \n\n \u5206\u9875<\/td>\n \u6570\u636e\u4e00\u6b21\u83b7\u53d6\u592a\u591a<\/td>\n \u7f51\u7edc \/ \u670d\u52a1\u7aef<\/td>\n<\/tr>\n \n \u65e0\u9650\u6eda\u52a8<\/td>\n \u8fde\u7eed\u83b7\u53d6\u6570\u636e<\/td>\n \u4ea4\u4e92 \/ \u6570\u636e\u83b7\u53d6<\/td>\n<\/tr>\n \n \u56fe\u7247\u61d2\u52a0\u8f7d<\/td>\n \u56fe\u7247\u8d44\u6e90\u592a\u591a<\/td>\n \u7f51\u7edc \/ \u56fe\u7247<\/td>\n<\/tr>\n \n \u865a\u62df\u5217\u8868<\/td>\n DOM \u8282\u70b9\u592a\u591a<\/td>\n React \/ DOM \/ \u6d4f\u89c8\u5668<\/td>\n<\/tr>\n \n React.memo<\/td>\n \u91cd\u590d\u6e32\u67d3<\/td>\n React<\/td>\n<\/tr>\n \n requestAnimationFrame<\/td>\n \u9ad8\u9891\u66f4\u65b0<\/td>\n \u6d4f\u89c8\u5668\u5e27\u8c03\u5ea6<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\n\u4e8c\u5341\u516d\u3001\u9762\u8bd5\u9898：\u5982\u679c\u9762\u8bd5\u5b98\u95ee\u201cReact \u4e2d\u5982\u4f55\u4f18\u5316\u8d85\u957f\u5217\u8868\u201d，\u5e94\u8be5\u600e\u4e48\u56de\u7b54？<\/h2>\n
\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）<\/h4>\n
\n\u63a8\u8350\u56de\u7b54\u903b\u8f91<\/h4>\n
\n \u2193
\n\u6570\u636e\u83b7\u53d6\u8fc7\u591a？
\n \u2193
\n\u5206\u9875 \/ \u65e0\u9650\u6eda\u52a8<\/p>\n
\n \u2193
\n\u865a\u62df\u5217\u8868<\/p>\n
\n \u2193
\nReact.memo \/ \u7a33\u5b9a props<\/p>\n
\n \u2193
\n\u62c6\u5206\u7ec4\u4ef6 \/ useMemo \/ \u9884\u8ba1\u7b97<\/p>\n
\n \u2193
\n\u56fe\u7247\u61d2\u52a0\u8f7d \/ \u54cd\u5e94\u5f0f\u56fe\u7247<\/p>\n
\n \u2193
\nrequestAnimationFrame \/ \u5408\u7406\u8282\u6d41<\/p>\n
\n \u2193
\n\u9ad8\u5ea6\u7f13\u5b58 + ResizeObserver<\/p>\n
\n \u2193
\n\u8003\u8651\u5206\u9875 \/ \u670d\u52a1\u7aef\u6e32\u67d3 \/ \u9884\u6e32\u67d3<\/p>\n
\n\u4e8c\u5341\u4e03\u3001\u9762\u8bd5\u9898：\u865a\u62df\u5217\u8868\u7684\u771f\u6b63\u6838\u5fc3\u77db\u76fe\u662f\u4ec0\u4e48？<\/h2>\n
\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）<\/h4>\n
\n\u4e3b\u8981\u77db\u76fe<\/h4>\n
\n+
\n\u5c11\u91cf\u7f13\u51b2\u533a\u57df<\/p>\n
\n\u6b21\u8981\u77db\u76fe<\/h4>\n
\nvs
\n\u771f\u5b9e DOM \u4f4d\u7f6e<\/p>\n
\nvs
\n\u6eda\u52a8\u6d41\u7545\u5ea6<\/p>\n
\nvs
\noverscan<\/p>\n
\nvs
\n\u52a8\u6001\u9ad8\u5ea6<\/p>\n
\nvs
\n\u952e\u76d8\u5bfc\u822a<\/p>\n
\nvs
\nSEO \/ \u6d4f\u89c8\u5668\u67e5\u627e<\/p>\n
\n\u4e8c\u5341\u516b\u3001\u9762\u8bd5\u9898：\u4e3a\u4ec0\u4e48\u865a\u62df\u5217\u8868\u80fd\u591f\u8ba9 10 \u4e07\u6761\u6570\u636e\u4ecd\u7136\u4fdd\u6301\u8f83\u597d\u7684\u6eda\u52a8\u6027\u80fd？<\/h2>\n
\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）<\/h4>\n
\n\u666e\u901a\u5217\u8868<\/h4>\n
\n \u2193
\n100000 DOM
\n \u2193
\n\u6eda\u52a8
\n \u2193
\n\u6d4f\u89c8\u5668\u7ef4\u62a4\u5de8\u5927 DOM<\/p>\n
\n\u865a\u62df\u5217\u8868<\/h4>\n
\n \u2193
\n\u5f53\u524d\u7a97\u53e3\u7ea6 20 \u6761
\n \u2193
\n\u5b9e\u9645 DOM \u7ea6 20～50 \u4e2a
\n \u2193
\n\u6eda\u52a8
\n \u2193
\n\u7a97\u53e3\u4ece：<\/p>\n
\n\u53ea\u9700\u8981\u589e\u5220\/\u590d\u7528\u5c11\u91cf\u8282\u70b9<\/p>\n
\n\u4e8c\u5341\u4e5d\u3001\u6700\u7ec8\u6ee1\u5206\u7b54\u6848<\/h2>\n
\u9762\u8bd5\u5b98：React \u4e2d\u5982\u4f55\u5b9e\u73b0\u865a\u62df\u5217\u8868？\u4e3a\u4ec0\u4e48\u865a\u62df\u5217\u8868\u53ef\u4ee5\u4f18\u5316\u957f\u5217\u8868\u6027\u80fd？<\/h3>\n
\u6ee1\u5206\u56de\u7b54<\/h4>\n
\n \u2193
\n\u5206\u9875 \/ \u65e0\u9650\u6eda\u52a8<\/p>\n
\n \u2193
\n\u865a\u62df\u5217\u8868<\/p>\n
\n \u2193
\nReact.memo \/ \u7a33\u5b9a props<\/p>\n
\n \u2193
\n\u7ec4\u4ef6\u62c6\u5206 \/ useMemo \/ \u9884\u8ba1\u7b97<\/p>\n
\n \u2193
\n\u56fe\u7247\u61d2\u52a0\u8f7d<\/p>\n
\n \u2193
\nrequestAnimationFrame \/ \u5408\u7406\u8282\u6d41<\/p>\n
\n\u4e09\u5341\u3001\u6700\u540e\u8bb0\u5fc6\u7248：\u865a\u62df\u5217\u8868\u9762\u8bd5\u53ea\u8bb0\u4f4f\u8fd9 8 \u53e5\u8bdd<\/h2>\n
\u2460 \u4e3a\u4ec0\u4e48\u505a？<\/h4>\n
\u2461 \u6838\u5fc3\u601d\u60f3？<\/h4>\n
\u2462 \u600e\u4e48\u77e5\u9053\u6e32\u67d3\u54ea\u4e9b？<\/h4>\n
\u2463 \u4e3a\u4ec0\u4e48\u9700\u8981\u603b\u9ad8\u5ea6？<\/h4>\n
\u2464 \u4e3a\u4ec0\u4e48\u7edd\u5bf9\u5b9a\u4f4d？<\/h4>\n
\u2465 \u4e3a\u4ec0\u4e48 overscan？<\/h4>\n
\u2466 \u52a8\u6001\u9ad8\u5ea6\u600e\u4e48\u529e？<\/h4>\n
\u2467 \u6709\u4ec0\u4e48\u9650\u5236？<\/h4>\n
\n\u4e00\u53e5\u8bdd\u7ec8\u6781\u603b\u7ed3<\/h3>\n
\n=
\n\u7528\u201c\u603b\u9ad8\u5ea6\u201d\u6a21\u62df\u5b8c\u6574\u5217\u8868
\n+
\n\u7528\u201c\u53ef\u89c6\u533a\u8ba1\u7b97\u201d\u51b3\u5b9a\u6e32\u67d3\u8303\u56f4
\n+
\n\u7528\u201coverscan\u201d\u4fdd\u8bc1\u6eda\u52a8\u4f53\u9a8c
\n+
\n\u7528\u201c\u7edd\u5bf9\u5b9a\u4f4d\u201d\u6062\u590d\u771f\u5b9e\u4f4d\u7f6e
\n+
\n\u7528\u201c\u5c11\u91cf DOM\u201d\u6362\u53d6\u957f\u5217\u8868\u6027\u80fd<\/p>\n
\n\u4e00\u3001\u9762\u8bd5\u9898：React \u4e3a\u4ec0\u4e48\u9700\u8981\u865a\u62df\u5217\u8868？\u957f\u5217\u8868\u7684\u6027\u80fd\u74f6\u9888\u5728\u54ea\u91cc？
\n\u6838\u5fc3\u601d\u8def（\u4e00\u53e5\u8bdd）
\n\u957f\u5217\u8868\u771f\u6b63\u7684\u95ee\u9898\u4e0d\u662f\u201c\u6570\u636e\u591a\u201d，\u800c\u662f\u4e00\u6b21\u6027\u521b\u5efa\u3001\u6e32\u67d3\u548c\u7ef4\u62a4\u4e86\u8fc7\u591a\u7684 DOM \u8282\u70b9\u4ee5\u53ca\u5bf9\u5e94\u7684 React \u7ec4\u4ef6\u6811，\u56e0\u6b64\u865a\u62df\u5217\u8868\u901a\u8fc7\u201c\u53ea\u6e32\u67d3\u5f53\u524d\u9700\u8981\u770b\u5230\u7684\u5c11\u91cf\u8282\u70b9\u201d\u964d\u4f4e\u5b9e\u9645\u6e32\u67d3\u6210\u672c\u3002\u89e3\u51b3\u65b9\u6848\u6d41\u7a0b\u56fe
\n\u5927\u91cf\u5217\u8868\u6570\u636e\u2193
\n\u4e00\u6b21\u6027\u6e32\u67d3\u5168\u90e8\u5217\u8868\u9879\u2193
\n\u4ea7\u751f\u5927\u91cf React El<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[12409,723],"topic":[],"class_list":["post-108718","post","type-post","status-publish","format-standard","hentry","category-server","tag-12409","tag-react"],"yoast_head":"\n