| 1 | import { useContext, useLayoutEffect, useMemo, useRef } from 'react'; |
| 2 | import { RevealContext } from '../reveal-context'; |
| 3 | import type { CodeProps } from '../types'; |
| 4 | |
| 5 | type HighlightPlugin = { |
| 6 | highlightBlock?: (block: HTMLElement) => void; |
| 7 | }; |
| 8 | |
| 9 | function normalizeCode(code: string) { |
| 10 | const lines = code.replace(/\r\n/g, '\n').split('\n'); |
| 11 | |
| 12 | while (lines.length && lines[0].trim().length === 0) lines.shift(); |
| 13 | while (lines.length && lines[lines.length - 1].trim().length === 0) lines.pop(); |
| 14 | |
| 15 | if (!lines.length) return ''; |
| 16 | |
| 17 | const minIndent = lines |
| 18 | .filter((line) => line.trim().length > 0) |
| 19 | .reduce( |
| 20 | (acc, line) => Math.min(acc, line.match(/^\s*/)?.[0].length ?? 0), |
| 21 | Number.POSITIVE_INFINITY |
| 22 | ); |
| 23 | |
| 24 | return lines.map((line) => line.slice(minIndent)).join('\n'); |
| 25 | } |
| 26 | |
| 27 | function cleanupGeneratedFragments(block: HTMLElement) { |
| 28 | const pre = block.parentElement; |
| 29 | if (!pre) return; |
| 30 | |
| 31 | // RevealHighlight creates extra <code.fragment> nodes for each highlight step (e.g. "1|3"). |
| 32 | // Remove previously generated nodes before re-highlighting to avoid duplicate steps. |
| 33 | Array.from(pre.children).forEach((child) => { |
| 34 | if ( |
| 35 | child !== block && |
| 36 | child instanceof HTMLElement && |
| 37 | child.tagName === 'CODE' && |
| 38 | child.classList.contains('fragment') |
| 39 | ) { |
| 40 | child.remove(); |
| 41 | } |
| 42 | }); |
| 43 | } |
| 44 | |
| 45 | export function Code({ |
| 46 | children, |
| 47 | code, |
| 48 | language, |
| 49 | trim = true, |
| 50 | lineNumbers, |
| 51 | startFrom, |
| 52 | noEscape, |
| 53 | codeClassName, |
| 54 | codeStyle, |
| 55 | codeProps, |
| 56 | className, |
| 57 | style, |
| 58 | ...rest |
| 59 | }: CodeProps) { |
| 60 | const deck = useContext(RevealContext); |
| 61 | const codeRef = useRef<HTMLElement>(null); |
| 62 | const lastHighlightSignatureRef = useRef<string>(''); |
| 63 | |
| 64 | const rawCode = typeof code === 'string' ? code : typeof children === 'string' ? children : ''; |
| 65 | const normalizedCode = useMemo(() => (trim ? normalizeCode(rawCode) : rawCode), [rawCode, trim]); |
| 66 | const lineNumbersValue = |
| 67 | lineNumbers === true |
| 68 | ? '' |
| 69 | : lineNumbers === false || lineNumbers == null |
| 70 | ? undefined |
| 71 | : String(lineNumbers); |
| 72 | const codeClasses = [language, codeClassName].filter(Boolean).join(' '); |
| 73 | const preClasses = ['code-wrapper', className].filter(Boolean).join(' '); |
| 74 | |
| 75 | useLayoutEffect(() => { |
| 76 | const block = codeRef.current; |
| 77 | if (!block || !deck) return; |
| 78 | |
| 79 | const plugin = deck.getPlugin?.('highlight') as HighlightPlugin | undefined; |
| 80 | if (!plugin || typeof plugin.highlightBlock !== 'function') return; |
| 81 | |
| 82 | const highlightSignature = [ |
| 83 | normalizedCode, |
| 84 | language || '', |
| 85 | codeClassName || '', |
| 86 | lineNumbersValue == null ? '__none__' : `lineNumbers:${lineNumbersValue}`, |
| 87 | startFrom == null ? '' : String(startFrom), |
| 88 | noEscape ? '1' : '0', |
| 89 | ].join('::'); |
| 90 | |
| 91 | if ( |
| 92 | lastHighlightSignatureRef.current === highlightSignature && |
| 93 | block.getAttribute('data-highlighted') === 'yes' |
| 94 | ) { |
| 95 | return; |
| 96 | } |
| 97 | |
| 98 | cleanupGeneratedFragments(block); |
| 99 | block.textContent = normalizedCode; |
| 100 | block.removeAttribute('data-highlighted'); |
| 101 | block.classList.remove('hljs'); |
| 102 | block.classList.remove('has-highlights'); |
| 103 | |
| 104 | // Restore source attributes before each highlight call since RevealHighlight mutates |
| 105 | // data-line-numbers on the original block when it expands multi-step highlights. |
| 106 | if (lineNumbersValue == null) block.removeAttribute('data-line-numbers'); |
| 107 | else block.setAttribute('data-line-numbers', lineNumbersValue); |
| 108 | if (startFrom == null) block.removeAttribute('data-ln-start-from'); |
| 109 | else block.setAttribute('data-ln-start-from', String(startFrom)); |
| 110 | if (noEscape) block.setAttribute('data-noescape', ''); |
| 111 | else block.removeAttribute('data-noescape'); |
| 112 | |
| 113 | plugin.highlightBlock(block); |
| 114 | |
| 115 | const slide = typeof block.closest === 'function' ? block.closest('section') : null; |
| 116 | if (slide && typeof deck.syncFragments === 'function') { |
| 117 | deck.syncFragments(slide as HTMLElement); |
| 118 | } |
| 119 | |
| 120 | lastHighlightSignatureRef.current = highlightSignature; |
| 121 | }, [deck, normalizedCode, language, codeClassName, lineNumbersValue, startFrom, noEscape]); |
| 122 | |
| 123 | return ( |
| 124 | <pre className={preClasses} style={style} {...rest}> |
| 125 | <code |
| 126 | {...codeProps} |
| 127 | ref={codeRef} |
| 128 | className={codeClasses || undefined} |
| 129 | style={codeStyle} |
| 130 | data-line-numbers={lineNumbersValue} |
| 131 | data-ln-start-from={startFrom} |
| 132 | data-noescape={noEscape ? '' : undefined} |
| 133 | > |
| 134 | {normalizedCode} |
| 135 | </code> |
| 136 | </pre> |
| 137 | ); |
| 138 | } |
| 139 |