feat: markdown 增量解析
This commit is contained in:
07akioni
@@ -1,155 +1,164 @@
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import { isValidElement, useMemo } from 'react'
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import ReactMarkdown from 'react-markdown'
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import type { Components, UrlTransform } from 'react-markdown'
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import rehypeKatex from 'rehype-katex'
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import remarkGfm from 'remark-gfm'
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import remarkMath from 'remark-math'
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import { CodeBlock } from './CodeBlock.tsx'
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import { remarkMathCompatibility } from './remarkMathCompatibility.ts'
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/**
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* Untrusted assistant-Markdown renderer over the direct mdast pipeline:
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* `parse.ts` grammars, the incremental streaming parser, and `render.tsx`.
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* While a message streams, all but the trailing two blocks freeze as cached
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* React elements and only the source tail behind them re-parses per chunk,
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* so per-chunk work tracks the tail size instead of the whole reply. Frozen
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* blocks keep their source-offset keys when they cross the freeze boundary,
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* so React reconciles instead of remounting. Known deviation while
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* streaming: a reference-style link or footnote whose definition sits on the
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* other side of the freeze boundary renders literally until the settled
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* full parse self-heals it.
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*/
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import { memo, useMemo, useRef } from 'react'
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import type { ReactNode } from 'react'
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import { IncrementalMarkdownParser } from './incremental.ts'
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import { parseGfm, parseGfmWithMath } from './parse.ts'
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import {
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collectReferenceTargets, createReferenceTargets, renderBlocks, renderFootnoteSection,
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wrapBlockChildren,
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} from './render.tsx'
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import type { MarkdownCodeLabels, MarkdownRenderContext, ReferenceTargets } from './render.tsx'
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import 'katex/dist/katex.min.css'
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import css from './MarkdownText.module.css'
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const streamingRemarkPlugins = [remarkGfm]
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const settledRemarkPlugins = [
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remarkGfm,
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remarkMathCompatibility,
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remarkMath,
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]
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const settledRehypePlugins = [rehypeKatex]
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export type { MarkdownCodeLabels } from './render.tsx'
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function sanitizeUrl(url: string): string {
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try {
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switch (new URL(url).protocol) {
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case 'http:':
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case 'https:':
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case 'mailto:':
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return url
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default:
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return ''
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/** One settled full render: parse with math, resolve references, append the footnote section. */
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function renderSettled(text: string, codeLabels: MarkdownCodeLabels | undefined): ReactNode[] {
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const root = parseGfmWithMath(text)
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const targets = createReferenceTargets()
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collectReferenceTargets(root.children, targets)
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const context: MarkdownRenderContext = {
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streaming: false,
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codeLabels,
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targets,
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footnoteOrder: [],
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footnoteCounts: new Map(),
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}
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const blocks = wrapBlockChildren(
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renderBlocks(root.children.map((node, index) => ({ node, key: index })), context),
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false,
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)
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const section = renderFootnoteSection(context)
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return section === null ? blocks : [...blocks, '\n', section]
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}
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/**
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* Streaming render state for one growing message: the incremental parser,
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* the frozen blocks' cached elements, and the reference/footnote state their
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* rendering consumed (footnote numbering assigned to frozen references is
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* final, so the tail continues from a copy of it each frame).
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*/
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class StreamingRenderer {
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private readonly parser = new IncrementalMarkdownParser(parseGfm)
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private generation = -1
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private frozenCount = 0
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private frozenElements: ReactNode[] = []
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private frozenTargets: ReferenceTargets = createReferenceTargets()
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private frozenFootnoteOrder: string[] = []
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private frozenFootnoteCounts = new Map<string, number>()
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private lastText: string | null = null
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private lastRendered: ReactNode[] = []
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/** @param codeLabels - Fence copy labels baked into cached elements; the owner replaces the renderer when they change. */
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constructor(private readonly codeLabels: MarkdownCodeLabels | undefined) {}
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/**
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* Render the current accumulated text. Idempotent per text value, so React
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* may re-execute the calling render freely.
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* @param text - The full accumulated markdown source.
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* @returns Frozen elements, re-rendered tail, and the footnote section.
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*/
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render(text: string): ReactNode[] {
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if (text === this.lastText) return this.lastRendered
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const { frozen, tail, generation } = this.parser.update(text)
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if (generation !== this.generation) {
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this.generation = generation
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this.frozenCount = 0
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this.frozenElements = []
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this.frozenTargets = createReferenceTargets()
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this.frozenFootnoteOrder = []
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this.frozenFootnoteCounts = new Map()
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}
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} catch {
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return ''
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const newlyFrozen = frozen.slice(this.frozenCount)
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collectReferenceTargets(newlyFrozen.map(block => block.node), this.frozenTargets)
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// Targets visible this frame: everything frozen so far plus the current
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// tail parse — a newly frozen block's references resolved against the
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// same parse tree its definitions came from.
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const frameTargets: ReferenceTargets = {
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definitions: new Map(this.frozenTargets.definitions),
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footnotes: new Map(this.frozenTargets.footnotes),
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}
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collectReferenceTargets(tail.map(block => block.node), frameTargets)
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if (newlyFrozen.length > 0) {
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const frozenContext: MarkdownRenderContext = {
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streaming: true,
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codeLabels: this.codeLabels,
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targets: frameTargets,
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footnoteOrder: this.frozenFootnoteOrder,
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footnoteCounts: this.frozenFootnoteCounts,
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}
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// Separator newlines are cached alongside the elements so the
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// assembled children match the settled pipeline's block wrapping.
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const batch = [...this.frozenElements]
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for (const element of renderBlocks(newlyFrozen, frozenContext)) {
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if (batch.length > 0) batch.push('\n')
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batch.push(element)
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}
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this.frozenElements = batch
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this.frozenCount = frozen.length
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}
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const tailContext: MarkdownRenderContext = {
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streaming: true,
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codeLabels: this.codeLabels,
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targets: frameTargets,
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footnoteOrder: [...this.frozenFootnoteOrder],
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footnoteCounts: new Map(this.frozenFootnoteCounts),
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}
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const children = [...this.frozenElements]
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for (const element of renderBlocks(tail, tailContext)) {
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if (children.length > 0) children.push('\n')
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children.push(element)
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}
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const section = renderFootnoteSection(tailContext)
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if (section !== null) children.push('\n', section)
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this.lastText = text
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this.lastRendered = children
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return this.lastRendered
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}
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}
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const safeUrl: UrlTransform = url => sanitizeUrl(url)
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/** Copy-button labels forwarded to fence CodeBlocks (this package is cordis-free, so copy arrives via props). */
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export interface MarkdownCodeLabels {
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/** Copy-button idle label. */
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copyLabel?: string | undefined
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/** Copy-button label during the post-copy confirmation window. */
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copiedLabel?: string | undefined
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}
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function remoteImageUrl(url: string): string | undefined {
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try {
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const protocol = new URL(url).protocol
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return protocol === 'http:' || protocol === 'https:' ? url : undefined
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} catch {
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return undefined
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}
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}
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/** Build the component table; while `streaming`, fences render the plain arm (see CodeBlock). */
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function buildComponents(streaming: boolean, codeLabels?: MarkdownCodeLabels): Components {
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return {
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a: ({ href = '', children }) => {
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const safeHref = sanitizeUrl(href)
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if (safeHref === '') return <>{children}</>
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const external = ['http:', 'https:'].includes(new URL(safeHref).protocol)
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return (
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<a
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href={safeHref}
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{...(external ? { target: '_blank', rel: 'noopener noreferrer' } : {})}
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>
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{children}
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</a>
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)
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},
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img: ({ alt = '', src = '' }) => {
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const imageSrc = remoteImageUrl(src)
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if (imageSrc === undefined) return <span className={css.imageAlt}>{alt}</span>
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return (
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<img
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className={css.image}
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src={imageSrc}
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alt={alt}
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loading="lazy"
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decoding="async"
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referrerPolicy="no-referrer"
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/>
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)
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},
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table: ({ children }) => (
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<div className={css.tableScroll}>
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<table>{children}</table>
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</div>
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),
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// Fenced blocks route through the shared CodeBlock (shiki for registered
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// grammars, identical-geometry plain fallback for unknown/absent
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// languages); inline code keeps the default <code> path (the :not(pre)
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// rule styles it). While the message streams, the fence renders the
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// plain arm — retokenizing a growing fence on every chunk is quadratic
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// main-thread work; the finalize swap highlights it once.
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pre: ({ children }) => {
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// The markdown pipeline always hands `pre` its single `code` element;
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// the undefined arm guards a react-markdown representation change.
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/* v8 ignore next 2 */
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const child = isValidElement<{ className?: string; children?: unknown }>(children) ? children : undefined
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const raw = child?.props.children
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// A fence whose content isn't one plain string (e.g. an empty fence)
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// keeps the stock <pre> rather than guessing.
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if (typeof raw !== 'string') return <pre>{children}</pre>
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const lang = /language-([\w-]+)/.exec(child?.props.className ?? '')?.[1]
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return (
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<CodeBlock
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code={raw}
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lang={streaming ? undefined : lang}
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copyLabel={codeLabels?.copyLabel}
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copiedLabel={codeLabels?.copiedLabel}
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/>
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)
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},
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}
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}
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const staticComponents = buildComponents(false)
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const streamingComponents = buildComponents(true)
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/**
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* Render untrusted assistant-authored Markdown as semantic React elements.
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* @param props - Markdown source text preserved by the session projection;
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* `streaming` renders fences and TeX plain (highlighting and KaTeX land on the finalize swap);
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* `codeLabels` forwards localized copy-button labels to fence CodeBlocks —
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* pass a reference-stable object (memoized per locale revision), because the
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* component table memoizes on its identity and a fresh literal per render
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* would rebuild it every streaming chunk.
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* `streaming` renders fences and TeX plain (highlighting and KaTeX land on
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* the finalize swap) and parses incrementally across chunks; `codeLabels`
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* forwards localized copy-button labels to fence CodeBlocks — pass a
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* reference-stable object (memoized per locale revision), because a new
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* identity discards the streaming render cache mid-message.
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* @returns A GFM document with TeX math rendered through KaTeX; raw HTML,
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* relative links, and unsafe protocols are disabled, while absolute HTTP(S)
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* images render directly.
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*/
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export function MarkdownText({ text, streaming = false, codeLabels }: {
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export const MarkdownText = memo(function MarkdownText({ text, streaming = false, codeLabels }: {
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text: string
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streaming?: boolean
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codeLabels?: MarkdownCodeLabels | undefined
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}) {
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// The label-free tables stay module-level singletons so the common case
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// keeps referential stability across renders without a hook.
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const components = useMemo(() => {
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if (codeLabels === undefined) return streaming ? streamingComponents : staticComponents
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return buildComponents(streaming, codeLabels)
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}, [streaming, codeLabels])
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return (
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<div className={css.markdown}>
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<ReactMarkdown
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remarkPlugins={streaming ? streamingRemarkPlugins : settledRemarkPlugins}
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rehypePlugins={streaming ? undefined : settledRehypePlugins}
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components={components}
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urlTransform={safeUrl}
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>
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{text}
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</ReactMarkdown>
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</div>
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)
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}
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const streamRef = useRef<StreamingRenderer | null>(null)
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const streamLabelsRef = useRef<MarkdownCodeLabels | undefined>(codeLabels)
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const children = useMemo(() => {
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if (!streaming) {
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streamRef.current = null
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return renderSettled(text, codeLabels)
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}
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if (streamRef.current === null || streamLabelsRef.current !== codeLabels) {
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streamRef.current = new StreamingRenderer(codeLabels)
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streamLabelsRef.current = codeLabels
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}
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return streamRef.current.render(text)
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}, [text, streaming, codeLabels])
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return <div className={css.markdown}>{children}</div>
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})
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@@ -0,0 +1,121 @@
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/**
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* Incremental block-level markdown parsing for an append-only text stream.
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*
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* Re-parsing the whole accumulated document on every streaming chunk is
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* quadratic in the final reply length. CommonMark block parsing is line-based
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* and appended text can only reshape the parse frontier — the last top-level
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* block (a paragraph becoming a setext heading or a table, a list continuing
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* after a blank line, an unclosed fence swallowing lines) — so earlier blocks
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* are final. This parser therefore freezes all but the trailing
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* {@link UNSTABLE_TAIL_BLOCKS} blocks and re-parses only the source tail
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* behind them: each source region is parsed O(1) times over the stream
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* instead of once per chunk.
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*
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* The freeze boundary comes from the parser's own `position` offsets, never
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* from custom source scanning. The cut sits at the *end offset* of the last
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* frozen block (not the next block's start): a following block's start offset
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* excludes up to three spaces of insignificant leading indentation, which is
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* harmless to drop, but cutting at the previous end also keeps the
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* inter-block blank lines in the tail so the sliced source stays verbatim.
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*
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* Known deviation, shared with any prefix-freeze scheme: micromark resolves
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* reference-style links and footnotes document-wide at parse time, so a
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* reference whose definition lands on the other side of the freeze boundary
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* renders literally until the settled full parse self-heals it.
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*/
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import type { Root, RootContent } from 'mdast'
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/**
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* Trailing blocks kept unstable. Appended text reshapes at most the last
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* block; the second-to-last is retained as safety margin so a freeze decision
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* never has to reason about the parse frontier.
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*/
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const UNSTABLE_TAIL_BLOCKS = 2
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/** A top-level mdast block plus a render key that is stable across chunks. */
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export interface PositionedBlock {
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/** The parsed block. Positions inside it are relative to its parse slice. */
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readonly node: RootContent
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/**
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* The block's start offset in the full source text. Stable from the frame
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* a block first appears through freezing, so React reconciles rather than
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* remounts when a block crosses the freeze boundary.
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*/
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readonly key: number
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}
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/** One {@link IncrementalMarkdownParser.update} result. */
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export interface IncrementalBlocks {
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/** Blocks that can no longer change; grows monotonically per generation. */
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readonly frozen: readonly PositionedBlock[]
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/** The re-parsed unstable tail (at most {@link UNSTABLE_TAIL_BLOCKS} blocks plus growth). */
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readonly tail: readonly PositionedBlock[]
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/** Bumped whenever non-append input discards the frozen prefix; callers drop caches keyed on it. */
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readonly generation: number
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}
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/**
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* A block's render key: its absolute source start offset. A position-less
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* node (a grammar is free to omit positions) falls back to a negative
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* list-index key, which keeps sibling keys unique without inventing offsets.
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*/
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function blockKey(node: RootContent, base: number, index: number): number {
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const offset = node.position?.start.offset
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return offset === undefined ? -(index + 1) : base + offset
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}
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/**
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* Append-only incremental parser over a caller-supplied grammar. One instance
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* accumulates one streaming document; non-append input resets it.
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*/
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export class IncrementalMarkdownParser {
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private prevText = ''
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private tailStart = 0
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private frozen: PositionedBlock[] = []
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private generation = 0
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private cached: IncrementalBlocks | null = null
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/** @param parse - Grammar shared with whatever renders the blocks, so boundaries agree. */
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constructor(private readonly parse: (text: string) => Root) {}
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/**
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* Fold the current accumulated text and return the frozen/tail split.
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* Idempotent for identical input (the previous result is returned as-is),
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* so callers may invoke it from render paths that re-execute.
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* @param text - The full accumulated markdown source.
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* @returns Frozen and tail blocks with stream-stable render keys.
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*/
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update(text: string): IncrementalBlocks {
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if (this.cached !== null && text === this.prevText) return this.cached
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if (!text.startsWith(this.prevText)) {
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this.prevText = ''
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this.tailStart = 0
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this.frozen = []
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this.generation += 1
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}
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this.prevText = text
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const base = this.tailStart
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const blocks = this.parse(text.slice(base)).children
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let firstUnstable = Math.max(0, blocks.length - UNSTABLE_TAIL_BLOCKS)
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if (firstUnstable > 0) {
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const cutEnd = blocks[firstUnstable - 1]?.position?.end.offset
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if (cutEnd === undefined) {
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// A grammar that omits positions leaves nothing to cut at; keep the
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// whole parse in the tail rather than guessing a boundary.
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firstUnstable = 0
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} else {
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for (const node of blocks.slice(0, firstUnstable)) {
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this.frozen.push({ node, key: blockKey(node, base, this.frozen.length) })
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}
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this.tailStart = base + cutEnd
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}
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}
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const tail = blocks.slice(firstUnstable).map((node, index) => ({
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node,
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key: blockKey(node, base, index),
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}))
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this.cached = { frozen: [...this.frozen], tail, generation: this.generation }
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return this.cached
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}
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}
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@@ -0,0 +1,84 @@
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/**
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* TeX-to-React via KaTeX, replicating the rehype-katex pipeline this renderer
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* replaced: the same three-arm error chain (strict render, `strict: 'ignore'`
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||||
* retry, error span) and a DOM-identical element tree, so settled math keeps
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* its exact markup. KaTeX emits an HTML string; the browser's own HTML parser
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* (`DOMParser`, applying the spec's SVG/MathML foreign-content attribute
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* adjustments KaTeX output relies on) turns it into a tree this module maps
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* onto React elements — KaTeX output is a static span/MathML/SVG vocabulary
|
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* with no raw user HTML, the same trust shiki's tree gets in CodeBlock.
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*/
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||||
|
||||
import { createElement } from 'react'
|
||||
import type { CSSProperties, ReactNode } from 'react'
|
||||
import katex from 'katex'
|
||||
|
||||
/**
|
||||
* Convert one inline `style` attribute string into React's style object.
|
||||
* KaTeX emits only plain kebab-case declarations (no custom properties and no
|
||||
* nameless declarations), so camel-casing the property is the whole mapping.
|
||||
*/
|
||||
function styleObject(css: string): CSSProperties {
|
||||
const style: Record<string, string> = {}
|
||||
for (const declaration of css.split(';')) {
|
||||
const colon = declaration.indexOf(':')
|
||||
if (colon === -1) continue
|
||||
const name = declaration.slice(0, colon).trim()
|
||||
const key = name.replace(/-([a-z])/g, (_, letter: string) => letter.toUpperCase())
|
||||
style[key] = declaration.slice(colon + 1).trim()
|
||||
}
|
||||
return style
|
||||
}
|
||||
|
||||
/** Map one parsed DOM node onto a React element (text nodes pass through). */
|
||||
function domToReact(node: ChildNode, key: number): ReactNode {
|
||||
if (node.nodeType === Node.TEXT_NODE) return node.textContent
|
||||
/* v8 ignore next 2 -- KaTeX output holds only elements and text; other
|
||||
node kinds cannot appear in its serialized vocabulary. */
|
||||
if (node.nodeType !== Node.ELEMENT_NODE) return null
|
||||
const element = node as Element
|
||||
const props: Record<string, unknown> = { key }
|
||||
for (const attribute of element.attributes) {
|
||||
if (attribute.name === 'class') props['className'] = attribute.value
|
||||
else if (attribute.name === 'style') props['style'] = styleObject(attribute.value)
|
||||
else props[attribute.name] = attribute.value
|
||||
}
|
||||
const children = [...element.childNodes].map(domToReact)
|
||||
return children.length === 0
|
||||
? createElement(element.localName, props)
|
||||
: createElement(element.localName, props, ...children)
|
||||
}
|
||||
|
||||
/**
|
||||
* Render TeX source to React elements through KaTeX.
|
||||
* @param value - The TeX source (math node value; fenced `math` blocks append
|
||||
* their trailing newline to match the replaced pipeline's text extraction).
|
||||
* @param displayMode - Display (block) versus inline rendering.
|
||||
* @returns KaTeX's element tree, or the error span when the source does not
|
||||
* parse (colored with KaTeX's stock `errorColor`, matching rehype-katex).
|
||||
*/
|
||||
export function renderTexToReact(value: string, displayMode: boolean): ReactNode {
|
||||
let html: string
|
||||
try {
|
||||
html = katex.renderToString(value, { displayMode, throwOnError: true })
|
||||
} catch (error) {
|
||||
try {
|
||||
html = katex.renderToString(value, { displayMode, strict: 'ignore', throwOnError: false })
|
||||
} catch {
|
||||
// KaTeX renders ParseErrors itself under throwOnError: false; only its
|
||||
// internal errors reach here, so mirror rehype-katex's manual span.
|
||||
/* v8 ignore next 8 */
|
||||
return (
|
||||
<span
|
||||
className="katex-error"
|
||||
style={{ color: '#cc0000' }}
|
||||
title={String(error)}
|
||||
>
|
||||
{value}
|
||||
</span>
|
||||
)
|
||||
}
|
||||
}
|
||||
const parsed = new DOMParser().parseFromString(html, 'text/html')
|
||||
return [...parsed.body.childNodes].map(domToReact)
|
||||
}
|
||||
+7
-11
@@ -8,10 +8,6 @@ import type { Construct, Extension, Previous, State, Tokenizer } from 'micromark
|
||||
|
||||
// oxlint-disable typescript/no-this-alias -- micromark binds tokenizer context only on the outer callback.
|
||||
|
||||
interface RemarkProcessor {
|
||||
data(): { micromarkExtensions?: Extension[] }
|
||||
}
|
||||
|
||||
const previousBackslash: Previous = function (code) {
|
||||
if (code !== codes.backslash) return true
|
||||
const tail = this.events.at(-1)
|
||||
@@ -342,12 +338,12 @@ const backslashMath: Extension = {
|
||||
}
|
||||
|
||||
/**
|
||||
* Add TeX backslash delimiters and same-line display-dollar blocks for remark-math.
|
||||
* The same processor must register remark-math to compile the emitted math tokens.
|
||||
* @returns Nothing.
|
||||
* TeX backslash delimiters and same-line display-dollar blocks as a micromark
|
||||
* syntax extension reusing `micromark-extension-math`'s token vocabulary; the
|
||||
* caller must also register `math()` on the same parse so the emitted tokens
|
||||
* compile to standard math nodes.
|
||||
* @returns The micromark syntax extension.
|
||||
*/
|
||||
export function remarkMathCompatibility(this: RemarkProcessor): undefined {
|
||||
const data = this.data()
|
||||
const extensions = data.micromarkExtensions ?? (data.micromarkExtensions = [])
|
||||
extensions.push(backslashMath)
|
||||
export function mathCompatibility(): Extension {
|
||||
return backslashMath
|
||||
}
|
||||
@@ -0,0 +1,41 @@
|
||||
/**
|
||||
* The markdown renderer's two mdast grammars, one per rendering arm. Both are
|
||||
* built from the same micromark extensions, so block boundaries and inline
|
||||
* semantics are identical wherever a document (or a document tail) is parsed:
|
||||
* the incremental streaming path, the settled path, and the plain-text
|
||||
* projection all agree on where blocks start and end.
|
||||
*/
|
||||
|
||||
import type { Root } from 'mdast'
|
||||
import { fromMarkdown } from 'mdast-util-from-markdown'
|
||||
import { gfmFromMarkdown } from 'mdast-util-gfm'
|
||||
import { mathFromMarkdown } from 'mdast-util-math'
|
||||
import { gfm } from 'micromark-extension-gfm'
|
||||
import { math } from 'micromark-extension-math'
|
||||
import { mathCompatibility } from './mathCompatibility.ts'
|
||||
|
||||
/**
|
||||
* Parse GFM markdown (the streaming arm's grammar: no math, so incomplete
|
||||
* TeX never flashes KaTeX errors mid-stream).
|
||||
* @param text - Markdown source.
|
||||
* @returns The mdast root.
|
||||
*/
|
||||
export function parseGfm(text: string): Root {
|
||||
return fromMarkdown(text, {
|
||||
extensions: [gfm()],
|
||||
mdastExtensions: [gfmFromMarkdown()],
|
||||
})
|
||||
}
|
||||
|
||||
/**
|
||||
* Parse GFM markdown plus TeX math with the compatibility delimiters
|
||||
* (the settled arm's grammar).
|
||||
* @param text - Markdown source.
|
||||
* @returns The mdast root.
|
||||
*/
|
||||
export function parseGfmWithMath(text: string): Root {
|
||||
return fromMarkdown(text, {
|
||||
extensions: [gfm(), mathCompatibility(), math()],
|
||||
mdastExtensions: [gfmFromMarkdown(), mathFromMarkdown()],
|
||||
})
|
||||
}
|
||||
@@ -0,0 +1,512 @@
|
||||
/**
|
||||
* Direct mdast→React markdown renderer. Replaces the react-markdown /
|
||||
* remark-rehype pipeline with one switch over parsed nodes so streaming can
|
||||
* cache frozen blocks as React elements; the rendered DOM is pinned
|
||||
* byte-for-byte by `tests/fixtures/markdown-dom` and must not drift.
|
||||
*
|
||||
* Untrusted-output policy (unchanged from the replaced pipeline): link and
|
||||
* image destinations pass a protocol allowlist, images additionally require
|
||||
* absolute HTTP(S), raw HTML renders as literal text (no HTML enters the
|
||||
* DOM), and KaTeX runs without trusted commands. Fragment-anchor URLs fail
|
||||
* the allowlist, so footnote references and back-references render as plain
|
||||
* text rather than in-page links.
|
||||
*
|
||||
* Merge-extensible node unions fall through the documented default (render
|
||||
* nothing) rather than ending in assertNever: grammars registered elsewhere
|
||||
* may add node types this renderer has no mapping for.
|
||||
*/
|
||||
|
||||
import { Fragment, createElement } from 'react'
|
||||
import type { Key, ReactNode } from 'react'
|
||||
import type * as Md from 'mdast'
|
||||
import type {} from 'mdast-util-math'
|
||||
import { normalizeUri } from 'micromark-util-sanitize-uri'
|
||||
import { CodeBlock } from './CodeBlock.tsx'
|
||||
import { renderTexToReact } from './katex.tsx'
|
||||
import type { PositionedBlock } from './incremental.ts'
|
||||
import css from './MarkdownText.module.css'
|
||||
|
||||
/** Copy-button labels forwarded to fence CodeBlocks (this package is cordis-free, so copy arrives via props). */
|
||||
export interface MarkdownCodeLabels {
|
||||
/** Copy-button idle label. */
|
||||
copyLabel?: string | undefined
|
||||
/** Copy-button label during the post-copy confirmation window. */
|
||||
copiedLabel?: string | undefined
|
||||
}
|
||||
|
||||
function sanitizeUrl(url: string): string {
|
||||
try {
|
||||
switch (new URL(url).protocol) {
|
||||
case 'http:':
|
||||
case 'https:':
|
||||
case 'mailto:':
|
||||
return url
|
||||
default:
|
||||
return ''
|
||||
}
|
||||
} catch {
|
||||
// Relative and otherwise unparsable destinations are disallowed alongside
|
||||
// disallowed protocols; new URL() has no other failure mode for strings.
|
||||
return ''
|
||||
}
|
||||
}
|
||||
|
||||
function remoteImageUrl(url: string): string | undefined {
|
||||
try {
|
||||
const protocol = new URL(url).protocol
|
||||
return protocol === 'http:' || protocol === 'https:' ? url : undefined
|
||||
} catch {
|
||||
// Same single failure mode as above: not an absolute URL.
|
||||
return undefined
|
||||
}
|
||||
}
|
||||
|
||||
/** Link/image reference targets collected from a document (first definition per identifier wins, as in CommonMark). */
|
||||
export interface ReferenceTargets {
|
||||
/** Link/image definitions keyed by upper-cased identifier. */
|
||||
definitions: Map<string, Md.Definition>
|
||||
/** Footnote definitions keyed by upper-cased identifier. */
|
||||
footnotes: Map<string, Md.FootnoteDefinition>
|
||||
}
|
||||
|
||||
/**
|
||||
* Create an empty {@link ReferenceTargets}.
|
||||
* @returns Fresh empty maps.
|
||||
*/
|
||||
export function createReferenceTargets(): ReferenceTargets {
|
||||
return { definitions: new Map(), footnotes: new Map() }
|
||||
}
|
||||
|
||||
/**
|
||||
* Record every definition and footnote definition under `nodes` into
|
||||
* `targets`, depth-first, keeping the first definition per identifier.
|
||||
* @param nodes - Subtrees to walk (top-level blocks or any nested children).
|
||||
* @param targets - Accumulator, typically shared across incremental segments.
|
||||
*/
|
||||
export function collectReferenceTargets(
|
||||
nodes: readonly Md.RootContent[],
|
||||
targets: ReferenceTargets,
|
||||
): void {
|
||||
for (const node of nodes) {
|
||||
if (node.type === 'definition') {
|
||||
const id = node.identifier.toUpperCase()
|
||||
if (!targets.definitions.has(id)) targets.definitions.set(id, node)
|
||||
} else if (node.type === 'footnoteDefinition') {
|
||||
const id = node.identifier.toUpperCase()
|
||||
if (!targets.footnotes.has(id)) targets.footnotes.set(id, node)
|
||||
}
|
||||
if ('children' in node) collectReferenceTargets(node.children, targets)
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* One render pass's state: immutable options and targets plus the footnote
|
||||
* numbering accumulated in document order while references render.
|
||||
*/
|
||||
export interface MarkdownRenderContext {
|
||||
/** Streaming arm: fences render plain and TeX stays literal. */
|
||||
readonly streaming: boolean
|
||||
/** Localized fence copy-button labels. */
|
||||
readonly codeLabels: MarkdownCodeLabels | undefined
|
||||
/** Reference targets visible to this pass. */
|
||||
readonly targets: ReferenceTargets
|
||||
/** Footnote identifiers in first-reference order; a footnote's number is its 1-based index here. */
|
||||
readonly footnoteOrder: string[]
|
||||
/** References rendered per identifier; drives the section's back-reference count. */
|
||||
readonly footnoteCounts: Map<string, number>
|
||||
}
|
||||
|
||||
/**
|
||||
* Render top-level blocks. Nodes that render nothing (definitions, unmapped
|
||||
* types) are dropped rather than kept as null placeholders, matching the
|
||||
* replaced pipeline's child lists so separator newlines land identically.
|
||||
* @param blocks - Blocks with their stream-stable render keys.
|
||||
* @param context - The pass state; footnote numbering mutates in document order.
|
||||
* @returns One React node per rendered block.
|
||||
*/
|
||||
export function renderBlocks(
|
||||
blocks: readonly PositionedBlock[],
|
||||
context: MarkdownRenderContext,
|
||||
): ReactNode[] {
|
||||
return blocks
|
||||
.map(block => renderNode(block.node, block.key, context))
|
||||
.filter(element => element !== null)
|
||||
}
|
||||
|
||||
/**
|
||||
* Interleave the newline text nodes the replaced pipeline emitted between
|
||||
* block-level children. They are invisible between elements but coalesce
|
||||
* into adjacent literal raw-HTML text, where the DOM parity fixtures pin
|
||||
* them.
|
||||
* @param elements - Rendered block children with empty renders already dropped.
|
||||
* @param edges - Also emit the leading and trailing newline (hast's loose wrap).
|
||||
* @returns The interleaved children.
|
||||
*/
|
||||
export function wrapBlockChildren(elements: readonly ReactNode[], edges: boolean): ReactNode[] {
|
||||
const wrapped: ReactNode[] = []
|
||||
for (const element of elements) {
|
||||
if (edges || wrapped.length > 0) wrapped.push('\n')
|
||||
wrapped.push(element)
|
||||
}
|
||||
if (edges && elements.length > 0) wrapped.push('\n')
|
||||
return wrapped
|
||||
}
|
||||
|
||||
/**
|
||||
* A block child rendered for a parent that must tell paragraphs apart from
|
||||
* other blocks (list items unwrap them when tight; footnote bodies receive
|
||||
* their back-references inside the trailing paragraph).
|
||||
*/
|
||||
type BlockEntry = { paragraph: ReactNode[] } | { element: ReactNode }
|
||||
|
||||
/** Render container children into {@link BlockEntry} values, dropping empty renders. */
|
||||
function renderBlockEntries(
|
||||
blocks: readonly Md.RootContent[],
|
||||
context: MarkdownRenderContext,
|
||||
): BlockEntry[] {
|
||||
const entries: BlockEntry[] = []
|
||||
for (const [index, block] of blocks.entries()) {
|
||||
if (block.type === 'paragraph') {
|
||||
entries.push({ paragraph: renderChildren(block.children, context) })
|
||||
} else {
|
||||
const element = renderNode(block, index, context)
|
||||
if (element !== null) entries.push({ element })
|
||||
}
|
||||
}
|
||||
return entries
|
||||
}
|
||||
|
||||
function renderChildren(
|
||||
nodes: readonly Md.RootContent[],
|
||||
context: MarkdownRenderContext,
|
||||
): ReactNode[] {
|
||||
return nodes.map((node, index) => renderNode(node, index, context))
|
||||
}
|
||||
|
||||
function renderNode(node: Md.RootContent, key: Key, context: MarkdownRenderContext): ReactNode {
|
||||
switch (node.type) {
|
||||
case 'text':
|
||||
return node.value
|
||||
case 'paragraph':
|
||||
return <p key={key}>{renderChildren(node.children, context)}</p>
|
||||
case 'heading':
|
||||
return createElement(`h${node.depth}`, { key }, ...renderChildren(node.children, context))
|
||||
case 'blockquote':
|
||||
return (
|
||||
<blockquote key={key}>
|
||||
{wrapBlockChildren(renderChildren(node.children, context).filter(child => child !== null), true)}
|
||||
</blockquote>
|
||||
)
|
||||
case 'thematicBreak':
|
||||
return <hr key={key} />
|
||||
case 'break':
|
||||
// The replaced pipeline emitted a newline text node after each <br>.
|
||||
return <Fragment key={key}><br />{'\n'}</Fragment>
|
||||
case 'strong':
|
||||
return <strong key={key}>{renderChildren(node.children, context)}</strong>
|
||||
case 'emphasis':
|
||||
return <em key={key}>{renderChildren(node.children, context)}</em>
|
||||
case 'delete':
|
||||
return <del key={key}>{renderChildren(node.children, context)}</del>
|
||||
case 'inlineCode':
|
||||
// Parity with mdast-util-to-hast: inline code renders line endings as spaces.
|
||||
return <code key={key}>{node.value.replace(/\r?\n|\r/g, ' ')}</code>
|
||||
case 'html':
|
||||
// No HTML parser enters the pipeline: raw HTML stays literal text.
|
||||
return node.value
|
||||
case 'code':
|
||||
return renderCode(node, key, context)
|
||||
case 'math':
|
||||
return <Fragment key={key}>{renderTexToReact(node.value, true)}</Fragment>
|
||||
case 'inlineMath':
|
||||
return <Fragment key={key}>{renderTexToReact(node.value, false)}</Fragment>
|
||||
case 'list':
|
||||
return renderList(node, key, context)
|
||||
case 'listItem':
|
||||
// Reachable only in hand-built trees: the grammar emits items inside lists.
|
||||
return renderListItem(node, listItemLoose(node), key, context)
|
||||
case 'table':
|
||||
return renderTable(node, key, context)
|
||||
case 'link':
|
||||
return renderAnchor(node.url, renderChildren(node.children, context), key)
|
||||
case 'linkReference':
|
||||
return renderLinkReference(node, key, context)
|
||||
case 'image':
|
||||
return renderImage(node.url, node.alt ?? '', key)
|
||||
case 'imageReference':
|
||||
return renderImageReference(node, key, context)
|
||||
case 'footnoteReference':
|
||||
return renderFootnoteReference(node, key, context)
|
||||
case 'definition':
|
||||
case 'footnoteDefinition':
|
||||
// Targets render elsewhere: definitions resolve references in place;
|
||||
// footnote bodies render in the trailing section.
|
||||
return null
|
||||
default:
|
||||
// Documented default for the merge-extensible union: node types without
|
||||
// a mapping (tableRow/tableCell outside a table, frontmatter, future
|
||||
// grammar contributions) render nothing.
|
||||
return null
|
||||
}
|
||||
}
|
||||
|
||||
function renderCode(node: Md.Code, key: Key, context: MarkdownRenderContext): ReactNode {
|
||||
const language = node.lang ?? undefined
|
||||
if (node.value === '') {
|
||||
// Parity: the replaced pipeline kept the stock <pre> for an empty fence.
|
||||
return (
|
||||
<pre key={key}>
|
||||
<code className={language === undefined ? undefined : `language-${language}`} />
|
||||
</pre>
|
||||
)
|
||||
}
|
||||
// The replaced pipeline recovered the grammar id from the hast class with
|
||||
// /language-([\w-]+)/, which truncates at the first non-word character.
|
||||
const lang = language === undefined ? undefined : /^[\w-]+/.exec(language)?.[0]
|
||||
if (!context.streaming && lang === 'math') {
|
||||
// ```math fences render as display TeX once settled (rehype-katex parity);
|
||||
// its text extraction saw the code block's trailing newline.
|
||||
return <Fragment key={key}>{renderTexToReact(`${node.value}\n`, true)}</Fragment>
|
||||
}
|
||||
return (
|
||||
<CodeBlock
|
||||
key={key}
|
||||
code={node.value}
|
||||
lang={context.streaming ? undefined : lang}
|
||||
copyLabel={context.codeLabels?.copyLabel}
|
||||
copiedLabel={context.codeLabels?.copiedLabel}
|
||||
/>
|
||||
)
|
||||
}
|
||||
|
||||
/** A list is loose when it or any of its items is spread; every item then keeps its paragraphs. */
|
||||
function listLoose(list: Md.List): boolean {
|
||||
return (list.spread ?? false) || list.children.some(listItemLoose)
|
||||
}
|
||||
|
||||
function listItemLoose(item: Md.ListItem): boolean {
|
||||
return item.spread ?? item.children.length > 1
|
||||
}
|
||||
|
||||
function renderList(node: Md.List, key: Key, context: MarkdownRenderContext): ReactNode {
|
||||
const loose = listLoose(node)
|
||||
const properties: { start?: number; className?: string } = {}
|
||||
if (typeof node.start === 'number' && node.start !== 1) properties.start = node.start
|
||||
if (node.children.some(item => typeof item.checked === 'boolean')) {
|
||||
properties.className = 'contains-task-list'
|
||||
}
|
||||
return createElement(
|
||||
node.ordered === true ? 'ol' : 'ul',
|
||||
{ key, ...properties },
|
||||
...node.children.map((item, index) => renderListItem(item, loose, index, context)),
|
||||
)
|
||||
}
|
||||
|
||||
function renderListItem(
|
||||
item: Md.ListItem,
|
||||
loose: boolean,
|
||||
key: Key,
|
||||
context: MarkdownRenderContext,
|
||||
): ReactNode {
|
||||
const entries = renderBlockEntries(item.children, context)
|
||||
const task = typeof item.checked === 'boolean'
|
||||
if (task) {
|
||||
const checkbox = <input key="task-checkbox" type="checkbox" checked={item.checked === true} disabled />
|
||||
const head = entries[0]
|
||||
if (head !== undefined && 'paragraph' in head) {
|
||||
head.paragraph = head.paragraph.length > 0 ? [checkbox, ' ', ...head.paragraph] : [checkbox]
|
||||
} else {
|
||||
entries.unshift({ paragraph: [checkbox] })
|
||||
}
|
||||
}
|
||||
// Newline placement and tight-paragraph unwrapping mirror
|
||||
// mdast-util-to-hast's list-item handler: a newline before every child
|
||||
// except a tight leading paragraph, and after a trailing non-paragraph
|
||||
// (or any trailing child when loose).
|
||||
const parts: ReactNode[] = []
|
||||
for (const [index, entry] of entries.entries()) {
|
||||
const isParagraph = 'paragraph' in entry
|
||||
if (loose || index !== 0 || !isParagraph) parts.push('\n')
|
||||
if (!isParagraph) parts.push(entry.element)
|
||||
else if (loose) parts.push(<p key={`p-${index}`}>{entry.paragraph}</p>)
|
||||
else parts.push(<Fragment key={`p-${index}`}>{entry.paragraph}</Fragment>)
|
||||
}
|
||||
const tail = entries[entries.length - 1]
|
||||
if (tail !== undefined && (loose || !('paragraph' in tail))) parts.push('\n')
|
||||
return (
|
||||
<li key={key} className={task ? 'task-list-item' : undefined}>
|
||||
{parts}
|
||||
</li>
|
||||
)
|
||||
}
|
||||
|
||||
function renderTable(node: Md.Table, key: Key, context: MarkdownRenderContext): ReactNode {
|
||||
const align = node.align ?? null
|
||||
const [headRow, ...bodyRows] = node.children
|
||||
return (
|
||||
<div key={key} className={css.tableScroll}>
|
||||
<table>
|
||||
{headRow !== undefined && <thead>{renderTableRow(headRow, 'th', align, 0, context)}</thead>}
|
||||
{bodyRows.length > 0 && (
|
||||
<tbody>
|
||||
{bodyRows.map((row, index) => renderTableRow(row, 'td', align, index + 1, context))}
|
||||
</tbody>
|
||||
)}
|
||||
</table>
|
||||
</div>
|
||||
)
|
||||
}
|
||||
|
||||
function renderTableRow(
|
||||
row: Md.TableRow,
|
||||
cellTag: 'th' | 'td',
|
||||
align: readonly Md.AlignType[] | null,
|
||||
key: Key,
|
||||
context: MarkdownRenderContext,
|
||||
): ReactNode {
|
||||
// With column alignment present, every row renders exactly one cell per
|
||||
// column, padding or truncating the row (mdast-util-to-hast parity).
|
||||
const length = align === null ? row.children.length : align.length
|
||||
const cells: ReactNode[] = []
|
||||
for (let index = 0; index < length; index++) {
|
||||
const cell = row.children[index]
|
||||
const alignValue = align?.[index]
|
||||
cells.push(createElement(
|
||||
cellTag,
|
||||
// hast-util-to-jsx-runtime's default tableCellAlignToStyle turned the
|
||||
// deprecated align attribute into an inline style; keep that DOM.
|
||||
{ key: index, style: alignValue == null ? undefined : { textAlign: alignValue } },
|
||||
...(cell === undefined ? [] : renderChildren(cell.children, context)),
|
||||
))
|
||||
}
|
||||
return <tr key={key}>{cells}</tr>
|
||||
}
|
||||
|
||||
function renderAnchor(url: string, children: ReactNode[], key: Key): ReactNode {
|
||||
const safeHref = sanitizeUrl(normalizeUri(url))
|
||||
if (safeHref === '') return <Fragment key={key}>{children}</Fragment>
|
||||
const external = ['http:', 'https:'].includes(new URL(safeHref).protocol)
|
||||
return (
|
||||
<a
|
||||
key={key}
|
||||
href={safeHref}
|
||||
{...(external ? { target: '_blank', rel: 'noopener noreferrer' } : {})}
|
||||
>
|
||||
{children}
|
||||
</a>
|
||||
)
|
||||
}
|
||||
|
||||
function renderImage(url: string, alt: string, key: Key): ReactNode {
|
||||
const imageSrc = remoteImageUrl(sanitizeUrl(normalizeUri(url)))
|
||||
if (imageSrc === undefined) {
|
||||
return <span key={key} className={css.imageAlt}>{alt}</span>
|
||||
}
|
||||
return (
|
||||
<img
|
||||
key={key}
|
||||
className={css.image}
|
||||
src={imageSrc}
|
||||
alt={alt}
|
||||
loading="lazy"
|
||||
decoding="async"
|
||||
referrerPolicy="no-referrer"
|
||||
/>
|
||||
)
|
||||
}
|
||||
|
||||
/** The bracketed source text a reference reverts to when its definition is missing. */
|
||||
function referenceSuffix(node: Md.LinkReference | Md.ImageReference): string {
|
||||
if (node.referenceType === 'collapsed') return '][]'
|
||||
if (node.referenceType === 'full') return `][${node.label ?? node.identifier}]`
|
||||
return ']'
|
||||
}
|
||||
|
||||
function renderLinkReference(
|
||||
node: Md.LinkReference,
|
||||
key: Key,
|
||||
context: MarkdownRenderContext,
|
||||
): ReactNode {
|
||||
const definition = context.targets.definitions.get(node.identifier.toUpperCase())
|
||||
const children = renderChildren(node.children, context)
|
||||
if (definition === undefined) {
|
||||
// The grammar only emits references whose definitions exist somewhere in
|
||||
// the same parse, but incremental segments and hand-built trees may still
|
||||
// present unresolved ones: revert to the bracketed source text.
|
||||
return <Fragment key={key}>{'['}{children}{referenceSuffix(node)}</Fragment>
|
||||
}
|
||||
return renderAnchor(definition.url, children, key)
|
||||
}
|
||||
|
||||
function renderImageReference(
|
||||
node: Md.ImageReference,
|
||||
key: Key,
|
||||
context: MarkdownRenderContext,
|
||||
): ReactNode {
|
||||
const definition = context.targets.definitions.get(node.identifier.toUpperCase())
|
||||
if (definition === undefined) return `![${node.alt ?? ''}${referenceSuffix(node)}`
|
||||
return renderImage(definition.url, node.alt ?? '', key)
|
||||
}
|
||||
|
||||
function renderFootnoteReference(
|
||||
node: Md.FootnoteReference,
|
||||
key: Key,
|
||||
context: MarkdownRenderContext,
|
||||
): ReactNode {
|
||||
const id = node.identifier.toUpperCase()
|
||||
const seen = context.footnoteCounts.get(id)
|
||||
if (seen === undefined) context.footnoteOrder.push(id)
|
||||
context.footnoteCounts.set(id, (seen ?? 0) + 1)
|
||||
// The in-page anchor fails the protocol allowlist, so only the numbered
|
||||
// superscript renders (matching the replaced pipeline's unwrapped link).
|
||||
return <sup key={key}>{String(context.footnoteOrder.indexOf(id) + 1)}</sup>
|
||||
}
|
||||
|
||||
/**
|
||||
* Render the trailing footnote section for every footnote referenced during
|
||||
* the pass, in first-reference order, with one plain-text back-reference
|
||||
* marker per rendered reference.
|
||||
* @param context - The pass state after all blocks rendered.
|
||||
* @returns The section, or null when no referenced footnote has a definition.
|
||||
*/
|
||||
export function renderFootnoteSection(context: MarkdownRenderContext): ReactNode | null {
|
||||
const items: ReactNode[] = []
|
||||
for (const id of context.footnoteOrder) {
|
||||
const definition = context.targets.footnotes.get(id)
|
||||
if (definition === undefined) continue
|
||||
const count = context.footnoteCounts.get(id) ?? 0
|
||||
const backrefs: ReactNode[] = []
|
||||
for (let reference = 1; reference <= count; reference++) {
|
||||
if (backrefs.length > 0) backrefs.push(' ')
|
||||
backrefs.push('↩')
|
||||
if (reference > 1) backrefs.push(<sup key={`re-${reference}`}>{String(reference)}</sup>)
|
||||
}
|
||||
const entries = renderBlockEntries(definition.children, context)
|
||||
const tail = entries[entries.length - 1]
|
||||
const body: ReactNode[] = entries.map((entry, index) => (
|
||||
'paragraph' in entry
|
||||
? (
|
||||
<p key={`p-${index}`}>
|
||||
{entry.paragraph}
|
||||
{entry === tail && <>{' '}{backrefs}</>}
|
||||
</p>
|
||||
)
|
||||
: entry.element
|
||||
))
|
||||
// Without a trailing paragraph the back-references join the block list
|
||||
// itself (and pick up the wrap newlines), as in the replaced pipeline.
|
||||
if (tail === undefined || !('paragraph' in tail)) body.push(...backrefs)
|
||||
items.push(
|
||||
<li key={id} id={`user-content-fn-${normalizeUri(id.toLowerCase())}`}>
|
||||
{wrapBlockChildren(body, true)}
|
||||
</li>,
|
||||
)
|
||||
}
|
||||
if (items.length === 0) return null
|
||||
return (
|
||||
<section key="footnotes" data-footnotes className="footnotes">
|
||||
<h2 id="footnote-label" className="sr-only">Footnotes</h2>
|
||||
<ol>{items}</ol>
|
||||
</section>
|
||||
)
|
||||
}
|
||||
Reference in New Issue
Block a user