feat(baoyu-md): add Mermaid preprocessing and utility modules

packages/baoyu-md/src/mermaid-utils.test.ts

@@ -0,0 +1,115 @@
+import assert from "node:assert/strict";
+import test from "node:test";
+
+import {
+  MERMAID_VERSION,
+  extractMermaidBlocks,
+  hashMermaidCode,
+  replaceMermaidBlocks,
+} from "./mermaid-utils.ts";
+
+test("extractMermaidBlocks finds fenced mermaid blocks at the top level", () => {
+  const markdown = `Intro
+
+\`\`\`mermaid
+graph TD
+  A --> B
+\`\`\`
+
+Outro`;
+
+  const blocks = extractMermaidBlocks(markdown);
+  assert.equal(blocks.length, 1);
+  assert.equal(blocks[0]!.code.trim(), "graph TD\n  A --> B");
+  assert.equal(blocks[0]!.infoString, "");
+  assert.ok(blocks[0]!.raw.includes("```mermaid"));
+});
+
+test("extractMermaidBlocks preserves info-string suffixes", () => {
+  const markdown = "```mermaid theme=dark\nflowchart LR\n  A --> B\n```";
+  const blocks = extractMermaidBlocks(markdown);
+  assert.equal(blocks.length, 1);
+  assert.equal(blocks[0]!.infoString, "theme=dark");
+});
+
+test("extractMermaidBlocks finds blocks nested inside lists", () => {
+  const markdown = `Steps:
+
+1. First, render the diagram:
+
+   \`\`\`mermaid
+   sequenceDiagram
+     Alice->>Bob: Hello
+   \`\`\`
+
+2. Then do something else.`;
+
+  const blocks = extractMermaidBlocks(markdown);
+  assert.equal(blocks.length, 1);
+  assert.equal(blocks[0]!.code.includes("sequenceDiagram"), true);
+});
+
+test("extractMermaidBlocks ignores non-mermaid fences and empty blocks", () => {
+  const markdown = `\`\`\`ts
+const x = 1;
+\`\`\`
+
+\`\`\`mermaid
+
+\`\`\`
+
+\`\`\`mermaidsomething
+not a real lang
+\`\`\``;
+
+  const blocks = extractMermaidBlocks(markdown);
+  assert.equal(blocks.length, 1);
+  assert.equal(blocks[0]!.infoString, "something");
+  assert.equal(blocks[0]!.code.trim(), "not a real lang");
+});
+
+test("replaceMermaidBlocks performs exact string replacement", () => {
+  const markdown = "before\n\n```mermaid\ngraph TD\nA-->B\n```\n\nafter";
+  const blocks = extractMermaidBlocks(markdown);
+  const map = new Map([[blocks[0]!.raw, "![diagram](img.png)"]]);
+  const replaced = replaceMermaidBlocks(markdown, map);
+  assert.equal(replaced, "before\n\n![diagram](img.png)\n\nafter");
+});
+
+test("replaceMermaidBlocks leaves markdown unchanged when no replacements match", () => {
+  const markdown = "hello\n\nworld";
+  const replaced = replaceMermaidBlocks(markdown, new Map([["nope", "x"]]));
+  assert.equal(replaced, markdown);
+});
+
+test("hashMermaidCode is stable for the same inputs", () => {
+  const a = hashMermaidCode({ code: "graph TD\nA-->B" });
+  const b = hashMermaidCode({ code: "graph TD\nA-->B" });
+  assert.equal(a, b);
+  assert.equal(a.length, 12);
+});
+
+test("hashMermaidCode defaults to 2x render scale", () => {
+  const implicit = hashMermaidCode({ code: "graph TD\nA-->B" });
+  const explicit = hashMermaidCode({ code: "graph TD\nA-->B", scale: 2 });
+  assert.equal(implicit, explicit);
+});
+
+test("hashMermaidCode ignores trailing whitespace", () => {
+  const a = hashMermaidCode({ code: "graph TD\nA-->B" });
+  const b = hashMermaidCode({ code: "graph TD\nA-->B   \n\n" });
+  assert.equal(a, b);
+});
+
+test("hashMermaidCode reflects theme/scale/background/version changes", () => {
+  const base = hashMermaidCode({ code: "graph TD\nA-->B" });
+  assert.notEqual(base, hashMermaidCode({ code: "graph TD\nA-->B", theme: "dark" }));
+  assert.notEqual(base, hashMermaidCode({ code: "graph TD\nA-->B", scale: 3 }));
+  assert.notEqual(base, hashMermaidCode({ code: "graph TD\nA-->B", minWidth: 860 }));
+  assert.notEqual(base, hashMermaidCode({ code: "graph TD\nA-->B", background: "#000" }));
+  assert.notEqual(base, hashMermaidCode({ code: "graph TD\nA-->B", version: "x.y.z" }));
+});
+
+test("MERMAID_VERSION matches the vendored bundle (10.x)", () => {
+  assert.match(MERMAID_VERSION, /^10\./);
+});