refactor: unify markdown formatting pipeline

src/signal/format.test.ts

@@ -0,0 +1,67 @@
+import { describe, expect, it } from "vitest";
+
+import { markdownToSignalText } from "./format.js";
+
+describe("markdownToSignalText", () => {
+  it("renders inline styles", () => {
+    const res = markdownToSignalText("hi _there_ **boss** ~~nope~~ `code`");
+
+    expect(res.text).toBe("hi there boss nope code");
+    expect(res.styles).toEqual([
+      { start: 3, length: 5, style: "ITALIC" },
+      { start: 9, length: 4, style: "BOLD" },
+      { start: 14, length: 4, style: "STRIKETHROUGH" },
+      { start: 19, length: 4, style: "MONOSPACE" },
+    ]);
+  });
+
+  it("renders links as label plus url when needed", () => {
+    const res = markdownToSignalText(
+      "see [docs](https://example.com) and https://example.com",
+    );
+
+    expect(res.text).toBe(
+      "see docs (https://example.com) and https://example.com",
+    );
+    expect(res.styles).toEqual([]);
+  });
+
+  it("applies spoiler styling", () => {
+    const res = markdownToSignalText("hello ||secret|| world");
+
+    expect(res.text).toBe("hello secret world");
+    expect(res.styles).toEqual([{ start: 6, length: 6, style: "SPOILER" }]);
+  });
+
+  it("renders fenced code blocks with monospaced styles", () => {
+    const res = markdownToSignalText(
+      "before\n\n```\nconst x = 1;\n```\n\nafter",
+    );
+
+    const prefix = "before\n\n";
+    const code = "const x = 1;\n";
+    const suffix = "\nafter";
+
+    expect(res.text).toBe(`${prefix}${code}${suffix}`);
+    expect(res.styles).toEqual([
+      { start: prefix.length, length: code.length, style: "MONOSPACE" },
+    ]);
+  });
+
+  it("renders lists without extra block markup", () => {
+    const res = markdownToSignalText("- one\n- two");
+
+    expect(res.text).toBe("• one\n• two");
+    expect(res.styles).toEqual([]);
+  });
+
+  it("uses UTF-16 code units for offsets", () => {
+    const res = markdownToSignalText("😀 **bold**");
+
+    const prefix = "😀 ";
+    expect(res.text).toBe(`${prefix}bold`);
+    expect(res.styles).toEqual([
+      { start: prefix.length, length: 4, style: "BOLD" },
+    ]);
+  });
+});