feat(compiler): bundle islands with a shared React chunk

splitting:true keeps React in one shared chunk so a page with several islands does not ship react-dom repeatedly. Island .tsx is compiled against React's JSX runtime via a Bun onLoad plugin. The repo's root tsconfig sets jsxImportSource to @wrnexus/core, so islands would otherwise compile to the HTML-string renderer and never mount. A @jsxImportSource pragma only affects the file carrying it, so injecting one into the generated entry is not enough — the injection has to happen per source file. App-authored islands stay plain .tsx. The JSX test asserts built output rather than generated entry text, because the entry-text assertion passed while the mechanism did not work. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
2026-08-18 15:22:58 +05:30
parent d269772a79
commit 06df9d66ae
2 changed files with 174 additions and 0 deletions
@@ -0,0 +1,61 @@
+import { afterAll, expect, test } from "bun:test";
+import { mkdtempSync, readFileSync, readdirSync, rmSync, writeFileSync } from "node:fs";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+
+import { assertReactAvailable, buildIslands, generateIslandEntry } from "../src/island-bundle.ts";
+
+const created: string[] = [];
+afterAll(() => {
+  for (const dir of created) rmSync(dir, { recursive: true, force: true });
+});
+
+test("generates an entry that re-exports the island component", () => {
+  const entry = generateIslandEntry({ name: "Chart", sourcePath: "/app/Chart.tsx" });
+  expect(entry).toContain("/app/Chart.tsx");
+  expect(entry).toContain("Chart");
+  expect(entry).not.toContain("react-dom/server");
+});
+
+test("island .tsx compiles against React's JSX runtime, not WRNexus's", async () => {
+  // The root tsconfig points jsxImportSource at @wrnexus/core, so an island
+  // would otherwise compile to WRNexus's HTML-string renderer and never mount.
+  // A pragma applies only to the file carrying it, so this asserts the built
+  // output rather than the generated entry text.
+  // The fixture must live inside the repo: Bun resolves `react` from the
+  // importing file's location, exactly as a real island resolves it from the
+  // app that installed react.
+  const root = mkdtempSync(join(process.cwd(), ".island-jsx-test-"));
+  created.push(root);
+  const source = join(root, "Chart.tsx");
+  writeFileSync(
+    source,
+    `export default function Chart({ title }: { title: string }) {
+       return <div className="chart">{title}</div>;
+     }`,
+  );
+
+  const outDir = join(root, "out");
+  await buildIslands({ islands: [{ name: "Chart", sourcePath: source }], outDir });
+
+  const built = readdirSync(outDir)
+    .filter((file) => file.endsWith(".js"))
+    .map((file) => readFileSync(join(outDir, file), "utf8"))
+    .join("\n");
+
+  expect(built).not.toContain("wrnexus");
+  expect(built).toMatch(/react\/jsx|jsxDEV|jsx_runtime/);
+});
+
+test("reports WRN-ISLAND-REACT-MISSING when react is not installed", () => {
+  const root = mkdtempSync(join(tmpdir(), "wrnexus-noreact-"));
+  writeFileSync(join(root, "package.json"), JSON.stringify({ name: "app" }));
+
+  const diagnostic = assertReactAvailable(root);
+  expect(diagnostic?.code).toBe("WRN-ISLAND-REACT-MISSING");
+  expect(diagnostic?.message).toContain("bun add react react-dom");
+});
+
+test("returns null when react resolves", () => {
+  expect(assertReactAvailable(process.cwd())).toBeNull();
+});