Add wikilink support as a markdown-it plugin with unit tests

tests/run-wikilinks-test.mjs

@@ -0,0 +1,107 @@
+// Standalone test for the Obsidian-style wikilink plugin.
+// Run with: node tests/run-wikilinks-test.mjs
+import esbuild from "esbuild";
+import MarkdownIt from "markdown-it";
+import fs from "fs";
+import os from "os";
+import path from "path";
+import url from "url";
+
+const out = path.join(os.tmpdir(), `folio-wikilinks-${process.pid}.mjs`);
+await esbuild.build({
+  entryPoints: [path.resolve("src/renderer/wikilinks.ts")],
+  bundle: true,
+  platform: "node",
+  format: "esm",
+  outfile: out,
+  write: true,
+  logLevel: "silent",
+});
+
+const mod = await import(url.pathToFileURL(out).href);
+const { wikilinkPlugin } = mod;
+
+const chapters = [
+  { id: "introduction-1", title: "Introduction" },
+  { id: "money-2", title: "Money" },
+];
+
+function makeMd() {
+  const md = new MarkdownIt({ html: false, linkify: true, typographer: true });
+  md.use(wikilinkPlugin, { chapters });
+  return md;
+}
+
+let failures = 0;
+function ok(cond, msg) {
+  if (cond) console.log("  ok -", msg);
+  else {
+    failures++;
+    console.error("FAIL -", msg);
+  }
+}
+
+const md = makeMd();
+
+// basic wikilink resolves by title (case-insensitive)
+const html1 = md.render("See [[Introduction]] for details.");
+ok(
+  html1.includes('<a href="folio:chapter/introduction-1" class="wikilink internal">Introduction</a>'),
+  "wikilink resolves by title -> internal link with chapter id"
+);
+
+// wikilink resolves by id
+const html2 = md.render("Link to [[introduction-1]] too.");
+ok(
+  html2.includes('href="folio:chapter/introduction-1"') &&
+    html2.includes("class=\"wikilink internal\""),
+  "wikilink resolves by chapter id"
+);
+
+// label-only match: title takes priority over id
+const html2b = md.render("[[Money]]");
+ok(html2b.includes('href="folio:chapter/money-2"'), "title match wins over id when both plausible");
+
+// missing wikilink renders as missing
+const html3 = md.render("A [[Nonexistent]] thing.");
+ok(
+  html3.includes('href="#"') && html3.includes('class="wikilink missing"'),
+  "unresolved wikilink renders as missing"
+);
+
+// alias / label syntax [[target|label]]
+const html4 = md.render("[[Introduction|custom label]]");
+ok(
+  html4.includes('href="folio:chapter/introduction-1"') &&
+    html4.includes(">custom label<"),
+  "alias syntax renders custom label pointing at resolved target"
+);
+
+// alias of a missing target is still missing
+const html5 = md.render("[[Nope|shown]]");
+ok(
+  html5.includes('class="wikilink missing"') && html5.includes(">shown<"),
+  "alias of missing target renders missing with alias label"
+);
+
+// regression: standard markdown links still work alongside wikilinks
+const html6 = md.render("[external](https://example.com) and [[Introduction]]");
+ok(html6.includes('<a href="https://example.com">external</a>'), "standard link still renders");
+ok(html6.includes('href="folio:chapter/introduction-1"'), "wikilink renders next to standard link");
+
+// regression: bold/italic still parse
+const html7 = md.render("**bold** and [[Introduction]]");
+ok(html7.includes("<strong>bold</strong>"), "emphasis still parses with wikilinks present");
+
+// nested brackets are not treated as wikilinks
+const html8 = md.render("not a [[a [[b]] c]] wikilink");
+ok(!html8.includes('class="wikilink"'), "nested brackets not parsed as wikilink");
+
+// empty [[ ]] is not a wikilink
+const html9 = md.render("empty [[] here");
+ok(!html9.includes('class="wikilink"'), "empty wikilink target not parsed");
+
+fs.rmSync(out, { force: true });
+
+console.log("\nWikilink tests: " + (failures === 0 ? "ALL PASSED" : failures + " FAILED"));
+process.exit(failures === 0 ? 0 : 1);