Markstream Svelte

• Confirm Svelte 5; ask Svelte 4 users to upgrade.
• Add package and only requested peers.
• Import CSS after resets; KaTeX CSS for math.
• Default to <MarkdownRender {content} />.
  • For streaming AI chat, keep content and use built-in smooth streaming first.
    • smoothStreaming="auto" is the default and activates when typewriter={true} or maxLiveNodes <= 0.
    • typewriter only controls the blinking cursor and defaults to false.
    • fade controls node enter and streamed-text fade animations and defaults to true.
  • Streaming vs recovering history: in chat UIs the same renderer starts streaming and later switches to history when final={true}.
    • Streaming: smoothStreaming="auto", fade={false}, typewriter={true}. Smooth pacing handles gradual appearance; fade would flicker.
    • Recovering history: smoothStreaming={false}, fade={true}, typewriter={false}. Content is already complete — pacing would slow it down, but fade gives a polished entry animation.
    • Dynamic switch: smoothStreaming={isStreaming ? 'auto' : false}, fade={!isStreaming}.
  • Use nodes + final for worker-preparsed content, shared AST stores, or custom AST control.
• Use $props() and callbacks.
• Workers: setKaTeXWorker, setMermaidWorker, workers/*?worker.
• Custom UI: scoped setCustomComponents, customId, customHtmlTags.
• Verify with svelte-check, build, or e2e.