mermaid-ascii: Mermaid to ASCII art playground via Go WASM

[simonw]

Clone https://github.com/AlexanderGrooff/mermaid-ascii to /tmp

Figure out if you can get it working in WebAssembly, like the most recently added project in this repo - then build a similar HTML playground called mermaid-ascii.html but with a ser if examples that fits this Go library (reusing existing samples from the Rust one if they work)

In-browser playground (mermaid-ascii.html) that renders Mermaid flowchart
and sequence diagram source as ASCII / Unicode box-drawing art, using
https://github.com/AlexanderGrooff/mermaid-ascii (MIT) compiled unmodified
to WebAssembly with the standard Go toolchain (GOOS=js GOARCH=wasm).

Follows the pattern of grok-mermaid.html but for the Go library:

• mermaid-ascii/build_wasm.sh clones upstream at a pinned commit, strips
  the cobra CLI and gin web-server entry points (nothing else imports
  them), adds a syscall/js shim exporting renderMermaidAscii(), and
  builds a 3.7 MB module (wasm-opt -Oz; ~1.1 MB gzipped).
• The page renders with the library's "html" style so classDef
  color:#hex classes work, sanitizing the unescaped span output via a
  strict tokenizer + textContent instead of innerHTML.
• Examples cover the features this library actually supports: labeled
  edges, A --> B & C fan-out, subgraphs,
  multi-line labels,
  classDef colors, and sequence diagrams with alt/loop/par fragments
  and notes (two examples reused from grok-mermaid where compatible).
• Controls: ASCII-only toggle, node padding X/Y, box padding, copy as
  text, permalink via URL fragment.
• tests/test_mermaid_ascii.py: 8 Playwright tests incl. an XSS probe.

Co-Authored-By: Claude Fable 5 noreply@anthropic.com
Claude-Session: https://claude.ai/code/session_01UPeaso82zQbKb67TTSVQ2e

[claude]

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