feat(agent): render markdown and highlight code in chat replies - #28
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Assistant responses were shown as raw text. Render them as sanitized markdown (marked + DOMPurify) with syntax-highlighted code blocks (highlight.js core + a lean language set). User messages stay literal. - markdown.ts: parse + sanitize; SSR falls back to escaped text - highlight.ts: post-render highlightElement, guarded against re-runs - app.postcss: variable-based hljs theme + prose styles, light/dark aware Closes #26 Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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Closes #26.
What
Model responses in the agent chat were shown as raw text. Now they render as sanitized markdown with syntax-highlighted code blocks.
How
src/lib/markdown.ts—renderMarkdown():marked(gfm) →DOMPurifysanitize. Model output is untrusted, so it's sanitized before{@html}; links open in a new tab withnoopener. SSR (nowindow) falls back to escaped plain text.src/lib/highlight.ts—highlight.jscore + a lean language set (js/ts/json/xml/css/bash/python/markdown) instead of the full ~200-language registry. Code blocks are highlighted on the live DOM inafterUpdate, guarded bydata-highlightedso re-renders skip finished blocks.agentChat.svelte— assistant messages render markdown; user messages stay literal (plain text).app.postcss— variable-based hljs palette (github light / github-dark) + prose styles, adapts to the app's.darkclass.Tests
markdown.test.ts— inline md, fenced code + language class, XSS stripping, linktarget/rel.agentChat.test.ts— assistant markdown becomes real DOM (<strong>,<pre><code>), fenced block gets.hljs-*spans, user asterisks stay literal.All 94 tests pass;
svelte-check,eslint, andvite buildclean.🤖 Generated with Claude Code