| 1 | import { useRef } from "react"; |
| 2 | import { useVirtualizer } from "@tanstack/react-virtual"; |
| 3 | import type { DiffProps } from "../DiffView"; |
| 4 | import { diffLines, diffRowsFromUnifiedDiff } from "../../lib/diff"; |
| 5 | import { highlightToHtml } from "../../lib/highlight"; |
| 6 | |
| 7 | // HljsDiff is the syntax-highlighted default behind the diff seam: an LCS line |
| 8 | // diff with a +/- gutter, each line highlighted in the target language. A real |
| 9 | // editor (Monaco DiffEditor / CodeMirror merge) would replace this via |
| 10 | // DiffView.tsx's lazy import. |
| 11 | const SIGN: Record<"ctx" | "add" | "del", string> = { ctx: " ", add: "+", del: "-" }; |
| 12 | |
| 13 | function lineNo(n?: number): string { |
| 14 | return typeof n === "number" ? String(n) : ""; |
| 15 | } |
| 16 | |
| 17 | export default function HljsDiff({ original = "", modified = "", diff = "", language, maxHeight }: DiffProps) { |
| 18 | const rows = diff ? diffRowsFromUnifiedDiff(diff) : diffLines(original, modified); |
| 19 | const scrollRef = useRef<HTMLDivElement>(null); |
| 20 | |
| 21 | const isVirtual = rows.length > 200; |
| 22 | |
| 23 | const virtualizer = useVirtualizer({ |
| 24 | count: isVirtual ? rows.length : 0, |
| 25 | getScrollElement: () => scrollRef.current, |
| 26 | estimateSize: () => 24, |
| 27 | overscan: 10, |
| 28 | directDomUpdates: true, |
| 29 | }); |
| 30 | |
| 31 | const renderRow = (r: typeof rows[0], idx: number) => ( |
| 32 | <div key={idx} className={`diff__row diff__row--${r.type}`}> |
| 33 | <span className="diff__gutter"> |
| 34 | <span className="diff__line diff__line--old">{lineNo(r.oldLine)}</span> |
| 35 | <span className="diff__line diff__line--new">{lineNo(r.newLine)}</span> |
| 36 | <span className="diff__sign">{SIGN[r.type]}</span> |
| 37 | </span> |
| 38 | <code |
| 39 | className="diff__text" |
| 40 | dangerouslySetInnerHTML={{ __html: highlightToHtml(r.text, language) }} |
| 41 | /> |
| 42 | </div> |
| 43 | ); |
| 44 | |
| 45 | return ( |
| 46 | <div |
| 47 | ref={scrollRef} |
| 48 | className="diff hljs" |
| 49 | style={{ |
| 50 | maxHeight: maxHeight || undefined, |
| 51 | overflow: (maxHeight || isVirtual) ? "auto" : undefined, |
| 52 | position: (maxHeight || isVirtual) ? "relative" : undefined, |
| 53 | }} |
| 54 | > |
| 55 | {isVirtual ? ( |
| 56 | <div |
| 57 | ref={virtualizer.containerRef} |
| 58 | className="diff__table" |
| 59 | style={{ |
| 60 | width: "100%", |
| 61 | position: "relative", |
| 62 | }} |
| 63 | > |
| 64 | {virtualizer.getVirtualItems().map((row) => { |
| 65 | const item = rows[row.index]; |
| 66 | if (!item) return null; |
| 67 | return ( |
| 68 | <div |
| 69 | key={row.key} |
| 70 | data-index={row.index} |
| 71 | ref={virtualizer.measureElement} |
| 72 | style={{ |
| 73 | position: "absolute", |
| 74 | top: 0, |
| 75 | left: 0, |
| 76 | width: "100%", |
| 77 | }} |
| 78 | > |
| 79 | {renderRow(item, row.index)} |
| 80 | </div> |
| 81 | ); |
| 82 | })} |
| 83 | </div> |
| 84 | ) : ( |
| 85 | <div className="diff__table"> |
| 86 | {rows.map((r, idx) => renderRow(r, idx))} |
| 87 | </div> |
| 88 | )} |
| 89 | </div> |
| 90 | ); |
| 91 | } |
| 92 |