Expose browser-safe email preview rendering

packages/email-renderer/test/browser.test.ts

@@ -0,0 +1,36 @@
+import { expect, test } from "bun:test";
+import { renderEmailPreview } from "../src/browser.ts";
+import { renderEmail } from "../src/email.ts";
+import type { BlockDocument } from "@wrnexus/blocks";
+
+const document: BlockDocument = {
+  schemaVersion: 1, kind: "email", meta: { subject: "Local preview", lang: "en" }, theme: { tokens: {} },
+  root: { id: "root", type: "layout.email-document", version: 1, props: { width: "600" }, styles: {}, slots: {
+    content: [{ id: "text", type: "content.text", version: 1, props: { text: "Hello {{recipientName|friend}}" }, styles: {}, slots: {} }],
+  } },
+};
+
+test("browser preview matches production HTML/text without server validators", async () => {
+  const before = structuredClone(document);
+  for (const direction of ["ltr", "rtl"] as const) {
+    const options = { direction, variables: { recipientName: "<script>unsafe</script>" } };
+    const preview = await renderEmailPreview(document, options);
+    const production = await renderEmail(document, options);
+    expect(preview.ok).toBe(true);
+    expect(production.ok).toBe(true);
+    if (preview.ok && production.ok) {
+      expect(preview.value.html).toBe(production.value.parts.html.content);
+      expect(preview.value.text).toBe(production.value.parts.text.content);
+      expect(preview.value.html).toContain("&lt;script&gt;");
+    }
+  }
+  expect(document).toEqual(before);
+});
+
+test("browser preview rejects unknown blocks without mutating them", async () => {
+  const invalid = structuredClone(document);
+  invalid.root.slots.content[0].type = "unknown.block";
+  const before = structuredClone(invalid);
+  expect((await renderEmailPreview(invalid)).ok).toBe(false);
+  expect(invalid).toEqual(before);
+});