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895/**
* Build optimization tests — verifies tree-shaking and chunking configuration
* is correctly applied to client builds.
*
* Tests the treeshake config, manualChunks function, and experimentalMinChunkSize
* to ensure large barrel-exporting libraries (e.g. mermaid) produce smaller bundles.
*/
import { describe, it, expect } from "vitest";
import {
clientManualChunks,
clientTreeshakeConfig,
computeLazyChunks,
} from "../packages/vinext/src/index.js";
// ─── clientTreeshakeConfig ────────────────────────────────────────────────────
describe("clientTreeshakeConfig", () => {
it("uses 'recommended' preset for safe defaults", () => {
expect(clientTreeshakeConfig.preset).toBe("recommended");
});
it("sets moduleSideEffects to 'no-external' for aggressive vendor DCE", () => {
// 'no-external' marks node_modules as side-effect-free (enabling DCE for
// barrel-heavy libraries) while preserving side effects for local modules
// (CSS imports, polyfills).
expect(clientTreeshakeConfig.moduleSideEffects).toBe("no-external");
});
});
// ─── clientManualChunks ───────────────────────────────────────────────────────
describe("clientManualChunks", () => {
it("groups react into 'framework' chunk", () => {
expect(clientManualChunks("/node_modules/react/index.js")).toBe("framework");
});
it("groups react-dom into 'framework' chunk", () => {
expect(clientManualChunks("/node_modules/react-dom/client.js")).toBe("framework");
});
it("groups scheduler into 'framework' chunk", () => {
expect(clientManualChunks("/node_modules/scheduler/index.js")).toBe("framework");
});
it("returns undefined for other node_modules (Rollup default splitting)", () => {
expect(clientManualChunks("/node_modules/mermaid/dist/mermaid.js")).toBeUndefined();
expect(clientManualChunks("/node_modules/lodash-es/lodash.js")).toBeUndefined();
expect(clientManualChunks("/node_modules/@mui/material/index.js")).toBeUndefined();
expect(clientManualChunks("/node_modules/d3-selection/src/index.js")).toBeUndefined();
});
it("returns undefined for user source files", () => {
expect(clientManualChunks("/src/components/App.tsx")).toBeUndefined();
expect(clientManualChunks("/src/pages/index.tsx")).toBeUndefined();
});
it("handles pnpm-style nested node_modules paths", () => {
const pnpmPath = "/node_modules/.pnpm/react@19.0.0/node_modules/react/index.js";
expect(clientManualChunks(pnpmPath)).toBe("framework");
});
it("handles scoped package names correctly", () => {
// Scoped packages should not be grouped into framework
expect(clientManualChunks("/node_modules/@tanstack/react-query/index.js")).toBeUndefined();
});
});
// ─── optimizeDeps.exclude — prevents esbuild scanning virtual module imports ─
describe("optimizeDeps.exclude for vinext", () => {
it("excludes vinext at top level for Pages Router builds", async () => {
const vinext = (await import("../packages/vinext/src/index.js")).default;
const plugins = vinext();
const mainPlugin = plugins.find(
(p: any) => p.name === "vinext:config" && typeof p.config === "function",
);
expect(mainPlugin).toBeDefined();
const os = await import("node:os");
const fsp = await import("node:fs/promises");
const path = await import("node:path");
const tmpDir = await fsp.mkdtemp(path.join(os.tmpdir(), "vinext-ts-test-optdeps-"));
const rootNodeModules = path.resolve(import.meta.dirname, "../node_modules");
await fsp.symlink(rootNodeModules, path.join(tmpDir, "node_modules"), "junction");
await fsp.mkdir(path.join(tmpDir, "pages"), { recursive: true });
await fsp.writeFile(
path.join(tmpDir, "pages", "index.tsx"),
`export default function Home() { return <h1>Home</h1>; }`,
);
await fsp.writeFile(
path.join(tmpDir, "next.config.mjs"),
`export default {};`,
);
try {
const mockConfig = { root: tmpDir, build: {}, plugins: [] };
const result = await (mainPlugin as any).config(mockConfig, { command: "build" });
expect(result.optimizeDeps?.exclude).toContain("vinext");
} finally {
await fsp.rm(tmpDir, { recursive: true, force: true }).catch(() => {});
}
}, 15000);
it("excludes vinext in all environments for App Router builds", async () => {
const vinext = (await import("../packages/vinext/src/index.js")).default;
const plugins = vinext();
const mainPlugin = plugins.find(
(p: any) => p.name === "vinext:config" && typeof p.config === "function",
);
expect(mainPlugin).toBeDefined();
const os = await import("node:os");
const fsp = await import("node:fs/promises");
const path = await import("node:path");
const tmpDir = await fsp.mkdtemp(path.join(os.tmpdir(), "vinext-ts-test-optdeps-app-"));
const rootNodeModules = path.resolve(import.meta.dirname, "../node_modules");
await fsp.symlink(rootNodeModules, path.join(tmpDir, "node_modules"), "junction");
await fsp.mkdir(path.join(tmpDir, "app"), { recursive: true });
await fsp.writeFile(
path.join(tmpDir, "app", "layout.tsx"),
`export default function RootLayout({ children }: { children: React.ReactNode }) { return <html><body>{children}</body></html>; }`,
);
await fsp.writeFile(
path.join(tmpDir, "app", "page.tsx"),
`export default function Home() { return <h1>Home</h1>; }`,
);
await fsp.writeFile(
path.join(tmpDir, "next.config.mjs"),
`export default {};`,
);
try {
const mockConfig = { root: tmpDir, build: {}, plugins: [] };
const result = await (mainPlugin as any).config(mockConfig, { command: "build" });
// Top-level
expect(result.optimizeDeps?.exclude).toContain("vinext");
// Per-environment
expect(result.environments.rsc.optimizeDeps?.exclude).toContain("vinext");
expect(result.environments.ssr.optimizeDeps?.exclude).toContain("vinext");
expect(result.environments.client.optimizeDeps?.exclude).toContain("vinext");
} finally {
await fsp.rm(tmpDir, { recursive: true, force: true }).catch(() => {});
}
}, 15000);
});
// ─── Treeshake config applied to Vite builds ──────────────────────────────────
describe("treeshake config integration", () => {
it("plugin config hook applies treeshake to non-SSR builds", async () => {
const vinext = (await import("../packages/vinext/src/index.js")).default;
const plugins = vinext();
// Find the main vinext plugin (has a config hook)
const mainPlugin = plugins.find(
(p: any) => p.name === "vinext:config" && typeof p.config === "function",
);
expect(mainPlugin).toBeDefined();
// Simulate a client build config (no build.ssr)
const os = await import("node:os");
const fsp = await import("node:fs/promises");
const path = await import("node:path");
const tmpDir = await fsp.mkdtemp(path.join(os.tmpdir(), "vinext-ts-test-"));
const rootNodeModules = path.resolve(import.meta.dirname, "../node_modules");
await fsp.symlink(rootNodeModules, path.join(tmpDir, "node_modules"), "junction");
await fsp.mkdir(path.join(tmpDir, "pages"), { recursive: true });
await fsp.writeFile(
path.join(tmpDir, "pages", "index.tsx"),
`export default function Home() { return <h1>Home</h1>; }`,
);
await fsp.writeFile(
path.join(tmpDir, "next.config.mjs"),
`export default {};`,
);
try {
const mockConfig = {
root: tmpDir,
build: {},
plugins: [],
};
const result = await (mainPlugin as any).config(mockConfig, { command: "build" });
// treeshake should be set on rollupOptions for non-SSR builds
expect(result.build.rollupOptions.treeshake).toEqual({
preset: "recommended",
moduleSideEffects: "no-external",
});
} finally {
await fsp.rm(tmpDir, { recursive: true, force: true }).catch(() => {});
}
}, 15000);
it("plugin config hook does NOT apply treeshake to SSR builds", async () => {
const vinext = (await import("../packages/vinext/src/index.js")).default;
const plugins = vinext();
const mainPlugin = plugins.find(
(p: any) => p.name === "vinext:config" && typeof p.config === "function",
);
expect(mainPlugin).toBeDefined();
const os = await import("node:os");
const fsp = await import("node:fs/promises");
const path = await import("node:path");
const tmpDir = await fsp.mkdtemp(path.join(os.tmpdir(), "vinext-ts-test-ssr-"));
const rootNodeModules = path.resolve(import.meta.dirname, "../node_modules");
await fsp.symlink(rootNodeModules, path.join(tmpDir, "node_modules"), "junction");
await fsp.mkdir(path.join(tmpDir, "pages"), { recursive: true });
await fsp.writeFile(
path.join(tmpDir, "pages", "index.tsx"),
`export default function Home() { return <h1>Home</h1>; }`,
);
await fsp.writeFile(
path.join(tmpDir, "next.config.mjs"),
`export default {};`,
);
try {
const mockConfig = {
root: tmpDir,
build: { ssr: "virtual:vinext-server-entry" },
plugins: [],
};
const result = await (mainPlugin as any).config(mockConfig, { command: "build" });
// treeshake should NOT be set for SSR builds
expect(result.build.rollupOptions.treeshake).toBeUndefined();
} finally {
await fsp.rm(tmpDir, { recursive: true, force: true }).catch(() => {});
}
}, 15000);
it("multi-env build scopes treeshake to client environment only", async () => {
// In App Router builds (multi-env), treeshake must NOT be set globally
// (which would leak into RSC/SSR) — it should only appear on the client
// environment's rollupOptions.
const vinext = (await import("../packages/vinext/src/index.js")).default;
const plugins = vinext();
const mainPlugin = plugins.find(
(p: any) => p.name === "vinext:config" && typeof p.config === "function",
);
expect(mainPlugin).toBeDefined();
const os = await import("node:os");
const fsp = await import("node:fs/promises");
const path = await import("node:path");
const tmpDir = await fsp.mkdtemp(path.join(os.tmpdir(), "vinext-ts-test-multienv-"));
const rootNodeModules = path.resolve(import.meta.dirname, "../node_modules");
await fsp.symlink(rootNodeModules, path.join(tmpDir, "node_modules"), "junction");
// Create an app/ directory to trigger multi-env mode (hasAppDir = true)
await fsp.mkdir(path.join(tmpDir, "app"), { recursive: true });
await fsp.writeFile(
path.join(tmpDir, "app", "layout.tsx"),
`export default function RootLayout({ children }: { children: React.ReactNode }) { return <html><body>{children}</body></html>; }`,
);
await fsp.writeFile(
path.join(tmpDir, "app", "page.tsx"),
`export default function Home() { return <h1>Home</h1>; }`,
);
await fsp.writeFile(
path.join(tmpDir, "next.config.mjs"),
`export default {};`,
);
try {
const mockConfig = {
root: tmpDir,
build: {},
plugins: [],
};
const result = await (mainPlugin as any).config(mockConfig, { command: "build" });
// Global rollupOptions should NOT have treeshake (would leak into RSC/SSR)
expect(result.build.rollupOptions.treeshake).toBeUndefined();
// Client environment should have treeshake
expect(result.environments.client.build.rollupOptions.treeshake).toEqual({
preset: "recommended",
moduleSideEffects: "no-external",
});
// RSC and SSR environments should NOT have treeshake
expect(result.environments.rsc.build?.rollupOptions?.treeshake).toBeUndefined();
expect(result.environments.ssr.build?.rollupOptions?.treeshake).toBeUndefined();
} finally {
await fsp.rm(tmpDir, { recursive: true, force: true }).catch(() => {});
}
}, 15000);
it("client output config includes experimentalMinChunkSize", async () => {
const vinext = (await import("../packages/vinext/src/index.js")).default;
const plugins = vinext();
const mainPlugin = plugins.find(
(p: any) => p.name === "vinext:config" && typeof p.config === "function",
);
expect(mainPlugin).toBeDefined();
const os = await import("node:os");
const fsp = await import("node:fs/promises");
const path = await import("node:path");
const tmpDir = await fsp.mkdtemp(path.join(os.tmpdir(), "vinext-ts-test-mcs-"));
const rootNodeModules = path.resolve(import.meta.dirname, "../node_modules");
await fsp.symlink(rootNodeModules, path.join(tmpDir, "node_modules"), "junction");
await fsp.mkdir(path.join(tmpDir, "pages"), { recursive: true });
await fsp.writeFile(
path.join(tmpDir, "pages", "index.tsx"),
`export default function Home() { return <h1>Home</h1>; }`,
);
await fsp.writeFile(
path.join(tmpDir, "next.config.mjs"),
`export default {};`,
);
try {
const mockConfig = {
root: tmpDir,
build: {},
plugins: [],
};
const result = await (mainPlugin as any).config(mockConfig, { command: "build" });
// For standalone client builds (non-SSR, non-multi-env),
// output config should include experimentalMinChunkSize
const output = result.build.rollupOptions.output;
expect(output).toBeDefined();
expect(output.experimentalMinChunkSize).toBe(10_000);
} finally {
await fsp.rm(tmpDir, { recursive: true, force: true }).catch(() => {});
}
}, 15000);
it("App Router client env gets manifest: true when Cloudflare plugin is present", async () => {
// When deploying to Cloudflare Workers, the client environment must produce
// a build manifest (manifest.json) so the vinext:cloudflare-build plugin can
// read dynamicImports and compute lazy chunks. Without this, all chunks get
// modulepreloaded on every page, defeating code-splitting for React.lazy()
// and next/dynamic boundaries.
const vinext = (await import("../packages/vinext/src/index.js")).default;
const plugins = vinext();
const mainPlugin = plugins.find(
(p: any) => p.name === "vinext:config" && typeof p.config === "function",
);
expect(mainPlugin).toBeDefined();
const os = await import("node:os");
const fsp = await import("node:fs/promises");
const path = await import("node:path");
const tmpDir = await fsp.mkdtemp(path.join(os.tmpdir(), "vinext-ts-test-cf-manifest-"));
const rootNodeModules = path.resolve(import.meta.dirname, "../node_modules");
await fsp.symlink(rootNodeModules, path.join(tmpDir, "node_modules"), "junction");
// Create an app/ directory to trigger App Router multi-env mode
await fsp.mkdir(path.join(tmpDir, "app"), { recursive: true });
await fsp.writeFile(
path.join(tmpDir, "app", "layout.tsx"),
`export default function RootLayout({ children }: { children: React.ReactNode }) { return <html><body>{children}</body></html>; }`,
);
await fsp.writeFile(
path.join(tmpDir, "app", "page.tsx"),
`export default function Home() { return <h1>Home</h1>; }`,
);
await fsp.writeFile(
path.join(tmpDir, "next.config.mjs"),
`export default {};`,
);
try {
// Simulate having the Cloudflare plugin in the plugin list.
// The vinext config hook detects it by checking plugin names.
const fakeCloudflarePlugin = { name: "vite-plugin-cloudflare" };
const mockConfig = {
root: tmpDir,
build: {},
plugins: [fakeCloudflarePlugin],
};
const result = await (mainPlugin as any).config(mockConfig, { command: "build" });
// Client environment should have manifest: true for lazy chunk detection
expect(result.environments).toBeDefined();
expect(result.environments.client).toBeDefined();
expect(result.environments.client.build.manifest).toBe(true);
// Without Cloudflare plugin, manifest should NOT be set (standard App Router)
const resultNoCf = await (mainPlugin as any).config({
root: tmpDir,
build: {},
plugins: [],
}, { command: "build" });
expect(resultNoCf.environments.client.build.manifest).toBeUndefined();
} finally {
await fsp.rm(tmpDir, { recursive: true, force: true }).catch(() => {});
}
}, 15000);
});
// ─── computeLazyChunks ────────────────────────────────────────────────────────
describe("computeLazyChunks", () => {
it("returns empty array for manifest with only entry chunks", () => {
const manifest = {
"src/main.ts": {
file: "assets/main-abc123.js",
isEntry: true,
imports: [],
},
};
expect(computeLazyChunks(manifest)).toEqual([]);
});
it("excludes statically imported chunks from lazy set", () => {
const manifest = {
"src/main.ts": {
file: "assets/main-abc123.js",
isEntry: true,
imports: ["src/utils.ts"],
},
"src/utils.ts": {
file: "assets/utils-def456.js",
},
};
expect(computeLazyChunks(manifest)).toEqual([]);
});
it("identifies dynamically-imported-only chunks as lazy", () => {
const manifest = {
"src/main.ts": {
file: "assets/main-abc123.js",
isEntry: true,
imports: ["src/framework.ts"],
dynamicImports: ["src/mermaid.ts"],
},
"src/framework.ts": {
file: "assets/framework-abc.js",
},
"src/mermaid.ts": {
file: "assets/mermaid-NOHMQCX5.js",
isDynamicEntry: true,
},
};
const lazy = computeLazyChunks(manifest);
expect(lazy).toContain("assets/mermaid-NOHMQCX5.js");
expect(lazy).not.toContain("assets/main-abc123.js");
expect(lazy).not.toContain("assets/framework-abc.js");
});
it("handles transitive static imports from entry", () => {
// entry -> A -> B (all static) — none should be lazy
const manifest = {
"src/main.ts": {
file: "assets/main.js",
isEntry: true,
imports: ["src/a.ts"],
},
"src/a.ts": {
file: "assets/a.js",
imports: ["src/b.ts"],
},
"src/b.ts": {
file: "assets/b.js",
},
};
expect(computeLazyChunks(manifest)).toEqual([]);
});
it("handles transitive dynamic imports as lazy", () => {
// entry -> A (static) -> B (dynamic) -> C (static from B)
// B and C should be lazy (B is only reachable via dynamic import)
// But C is statically imported by B, which is a dynamic entry
// Since B is not an entry, C is only reachable through B which is lazy
const manifest = {
"src/main.ts": {
file: "assets/main.js",
isEntry: true,
imports: ["src/a.ts"],
},
"src/a.ts": {
file: "assets/a.js",
dynamicImports: ["src/b.ts"],
},
"src/b.ts": {
file: "assets/b.js",
isDynamicEntry: true,
imports: ["src/c.ts"],
},
"src/c.ts": {
file: "assets/c.js",
},
};
const lazy = computeLazyChunks(manifest);
expect(lazy).toContain("assets/b.js");
expect(lazy).toContain("assets/c.js");
expect(lazy).not.toContain("assets/main.js");
expect(lazy).not.toContain("assets/a.js");
});
it("does not mark CSS files as lazy", () => {
const manifest = {
"src/main.ts": {
file: "assets/main.js",
isEntry: true,
dynamicImports: ["src/lazy.ts"],
},
"src/lazy.ts": {
file: "assets/lazy.js",
isDynamicEntry: true,
css: ["assets/lazy-styles.css"],
},
};
const lazy = computeLazyChunks(manifest);
expect(lazy).toContain("assets/lazy.js");
// CSS files are never in the lazy list (only .js files)
expect(lazy).not.toContain("assets/lazy-styles.css");
});
it("handles chunk shared between static and dynamic paths as eager", () => {
// If a chunk is statically imported by one module AND dynamically by another,
// it should NOT be lazy (it's reachable statically)
const manifest = {
"src/main.ts": {
file: "assets/main.js",
isEntry: true,
imports: ["src/shared.ts"],
dynamicImports: ["src/lazy.ts"],
},
"src/shared.ts": {
file: "assets/shared.js",
},
"src/lazy.ts": {
file: "assets/lazy.js",
isDynamicEntry: true,
imports: ["src/shared.ts"],
},
};
const lazy = computeLazyChunks(manifest);
expect(lazy).toContain("assets/lazy.js");
expect(lazy).not.toContain("assets/shared.js");
expect(lazy).not.toContain("assets/main.js");
});
it("returns empty array for empty manifest", () => {
expect(computeLazyChunks({})).toEqual([]);
});
it("handles circular static imports without infinite loop", () => {
const manifest = {
"src/entry.ts": {
file: "assets/entry.js",
isEntry: true,
imports: ["src/a.ts"],
},
"src/a.ts": {
file: "assets/a.js",
imports: ["src/b.ts"],
},
"src/b.ts": {
file: "assets/b.js",
imports: ["src/a.ts"], // circular: b -> a -> b -> ...
},
};
const lazy = computeLazyChunks(manifest);
expect(lazy).toEqual([]);
// All three are statically reachable from entry
});
it("handles multiple entry points", () => {
const manifest = {
"src/main.ts": {
file: "assets/main.js",
isEntry: true,
imports: ["src/a.ts"],
},
"src/other-entry.ts": {
file: "assets/other.js",
isEntry: true,
imports: ["src/b.ts"],
},
"src/a.ts": {
file: "assets/a.js",
},
"src/b.ts": {
file: "assets/b.js",
dynamicImports: ["src/lazy.ts"],
},
"src/lazy.ts": {
file: "assets/lazy.js",
isDynamicEntry: true,
},
};
const lazy = computeLazyChunks(manifest);
expect(lazy).toContain("assets/lazy.js");
expect(lazy).not.toContain("assets/main.js");
expect(lazy).not.toContain("assets/other.js");
expect(lazy).not.toContain("assets/a.js");
expect(lazy).not.toContain("assets/b.js");
});
it("handles manifest with no entry chunks (all chunks marked lazy)", () => {
// If no chunks have isEntry, the BFS starts with an empty queue
// and all JS files should be classified as lazy
const manifest = {
"src/orphan.ts": {
file: "assets/orphan.js",
imports: [],
},
"src/other.ts": {
file: "assets/other.js",
},
};
const lazy = computeLazyChunks(manifest);
expect(lazy).toContain("assets/orphan.js");
expect(lazy).toContain("assets/other.js");
});
it("handles realistic mermaid-like scenario", () => {
// Simulates: client entry -> page (dynamic) -> streamdown (static from page)
// streamdown -> mermaid (dynamic via React.lazy)
// The page itself is dynamic from the entry (vinext pattern), but
// mermaid is dynamic from streamdown — mermaid should be lazy
const manifest = {
"virtual:vinext-client-entry": {
file: "assets/vinext-client-entry-abc.js",
isEntry: true,
imports: ["node_modules/react/index.js", "node_modules/react-dom/client.js"],
dynamicImports: ["src/pages/index.tsx", "src/pages/about.tsx"],
},
"node_modules/react/index.js": {
file: "assets/framework-xyz.js",
},
"node_modules/react-dom/client.js": {
file: "assets/framework-xyz.js", // same chunk (manualChunks)
},
"src/pages/index.tsx": {
file: "assets/index-page.js",
isDynamicEntry: true,
imports: ["node_modules/streamdown/index.js"],
dynamicImports: [],
},
"src/pages/about.tsx": {
file: "assets/about-page.js",
isDynamicEntry: true,
},
"node_modules/streamdown/index.js": {
file: "assets/streamdown-chunk.js",
dynamicImports: ["node_modules/mermaid/dist/mermaid.js"],
},
"node_modules/mermaid/dist/mermaid.js": {
file: "assets/mermaid-NOHMQCX5.js",
isDynamicEntry: true,
},
};
const lazy = computeLazyChunks(manifest);
// Mermaid should be lazy — only reachable through dynamic imports
expect(lazy).toContain("assets/mermaid-NOHMQCX5.js");
// Pages are dynamic from entry — they should also be lazy
expect(lazy).toContain("assets/index-page.js");
expect(lazy).toContain("assets/about-page.js");
// streamdown is statically imported by a page, but the page itself is
// dynamic from entry — so streamdown is also lazy
expect(lazy).toContain("assets/streamdown-chunk.js");
// Framework and entry should NOT be lazy
expect(lazy).not.toContain("assets/vinext-client-entry-abc.js");
expect(lazy).not.toContain("assets/framework-xyz.js");
});
});
// ─── collectAssetTags lazy filtering (integration) ────────────────────────────
describe("collectAssetTags lazy chunk filtering", () => {
// collectAssetTags lives inside the generated virtual server entry and
// can't be imported directly. These tests verify the filtering behavior
// by simulating what collectAssetTags does: build a lazy set from
// computeLazyChunks output, then filter asset tags accordingly.
/**
* Simulates the collectAssetTags filtering logic:
* - Normalizes leading slashes from SSR manifest values
* - CSS files always get a <link rel="stylesheet"> tag
* - Non-lazy JS files get both modulepreload and script tags
* - Lazy JS files are skipped entirely
*
* Must match the actual collectAssetTags implementation in index.ts.
*/
function simulateAssetTagFiltering(
ssrManifestFiles: string[],
lazyChunks: string[],
): string[] {
const lazySet = new Set(lazyChunks);
const tags: string[] = [];
const seen = new Set<string>();
for (let tf of ssrManifestFiles) {
// Normalize: strip leading slash from SSR manifest values to avoid
// producing protocol-relative URLs (e.g. "//assets/chunk.js") and
// to ensure consistent matching against lazySet and seen set.
if (tf.startsWith("/")) tf = tf.slice(1);
if (seen.has(tf)) continue;
seen.add(tf);
if (tf.endsWith(".css")) {
tags.push(`<link rel="stylesheet" href="/${tf}" />`);
} else if (tf.endsWith(".js")) {
if (lazySet.has(tf)) continue;
tags.push(`<link rel="modulepreload" href="/${tf}" />`);
tags.push(`<script type="module" src="/${tf}" crossorigin></script>`);
}
}
return tags;
}
it("excludes lazy JS chunks from modulepreload and script tags", () => {
const buildManifest = {
"virtual:vinext-client-entry": {
file: "assets/entry.js",
isEntry: true,
imports: ["node_modules/react/index.js"],
dynamicImports: ["src/pages/index.tsx"],
},
"node_modules/react/index.js": {
file: "assets/framework.js",
},
"src/pages/index.tsx": {
file: "assets/page-index.js",
isDynamicEntry: true,
dynamicImports: ["node_modules/mermaid/dist/mermaid.js"],
},
"node_modules/mermaid/dist/mermaid.js": {
file: "assets/mermaid-big.js",
isDynamicEntry: true,
},
};
const lazyChunks = computeLazyChunks(buildManifest);
// SSR manifest for the index page would include these files
const ssrFiles = [
"assets/entry.js",
"assets/framework.js",
"assets/page-index.js",
"assets/mermaid-big.js",
];
const tags = simulateAssetTagFiltering(ssrFiles, lazyChunks);
// Entry and framework should have modulepreload + script tags
expect(tags).toContain('<link rel="modulepreload" href="/assets/entry.js" />');
expect(tags).toContain('<script type="module" src="/assets/entry.js" crossorigin></script>');
expect(tags).toContain('<link rel="modulepreload" href="/assets/framework.js" />');
// Page chunk and mermaid are lazy — should have NO tags at all
expect(tags.join("\n")).not.toContain("page-index.js");
expect(tags.join("\n")).not.toContain("mermaid-big.js");
});
it("always includes CSS files even for lazy chunks", () => {
const buildManifest = {
"src/entry.ts": {
file: "assets/entry.js",
isEntry: true,
dynamicImports: ["src/lazy.ts"],
},
"src/lazy.ts": {
file: "assets/lazy.js",
isDynamicEntry: true,
css: ["assets/lazy.css"],
},
};
const lazyChunks = computeLazyChunks(buildManifest);
const ssrFiles = ["assets/entry.js", "assets/lazy.js", "assets/lazy.css"];
const tags = simulateAssetTagFiltering(ssrFiles, lazyChunks);
// CSS always included (prevents FOUC)
expect(tags).toContain('<link rel="stylesheet" href="/assets/lazy.css" />');
// Lazy JS excluded
expect(tags.join("\n")).not.toContain("lazy.js");
// Entry included
expect(tags).toContain('<link rel="modulepreload" href="/assets/entry.js" />');
});
it("includes all chunks when lazy list is empty", () => {
const buildManifest = {
"src/entry.ts": {
file: "assets/entry.js",
isEntry: true,
imports: ["src/utils.ts"],
},
"src/utils.ts": {
file: "assets/utils.js",
},
};
const lazyChunks = computeLazyChunks(buildManifest);
expect(lazyChunks).toEqual([]); // nothing is lazy
const ssrFiles = ["assets/entry.js", "assets/utils.js"];
const tags = simulateAssetTagFiltering(ssrFiles, lazyChunks);
// Both should be present
expect(tags).toContain('<link rel="modulepreload" href="/assets/entry.js" />');
expect(tags).toContain('<link rel="modulepreload" href="/assets/utils.js" />');
expect(tags).toContain('<script type="module" src="/assets/entry.js" crossorigin></script>');
expect(tags).toContain('<script type="module" src="/assets/utils.js" crossorigin></script>');
});
it("normalizes leading slashes from SSR manifest values", () => {
// Vite's SSR manifest values include a leading "/" (from joinUrlSegments
// with base="/"), e.g. "/assets/framework-AbCd.js". Without normalization,
// prepending "/" produces protocol-relative URLs "//assets/..." which
// browsers interpret as https://assets/... (wrong host).
const buildManifest = {
"src/entry.ts": {
file: "assets/entry.js",
isEntry: true,
imports: ["node_modules/react/index.js"],
dynamicImports: ["src/pages/index.tsx"],
},
"node_modules/react/index.js": {
file: "assets/framework.js",
},
"src/pages/index.tsx": {
file: "assets/page-index.js",
isDynamicEntry: true,
},
};
const lazyChunks = computeLazyChunks(buildManifest);
// Simulate SSR manifest values WITH leading slashes (real Vite output)
const ssrFilesWithLeadingSlash = [
"/assets/entry.js",
"/assets/framework.js",
"/assets/page-index.js",
];
const tags = simulateAssetTagFiltering(ssrFilesWithLeadingSlash, lazyChunks);
// All URLs should have exactly one leading slash, not double
for (const tag of tags) {
expect(tag).not.toContain('href="//');
expect(tag).not.toContain('src="//');
}
// Entry and framework should be present with correct single-slash paths
expect(tags).toContain('<link rel="modulepreload" href="/assets/entry.js" />');
expect(tags).toContain('<script type="module" src="/assets/entry.js" crossorigin></script>');
expect(tags).toContain('<link rel="modulepreload" href="/assets/framework.js" />');
// Page chunk is lazy — should be excluded even with leading-slash input
expect(tags.join("\n")).not.toContain("page-index.js");
});
it("deduplicates entries when SSR manifest has leading slashes and client entry does not", () => {
// The client entry (from __VINEXT_CLIENT_ENTRY__) uses values without
// leading slashes ("assets/entry.js"), while SSR manifest values have
// them ("/assets/entry.js"). After normalization, both should resolve
// to the same key and the entry should appear only once.
const ssrFiles = [
"assets/entry.js", // added first (e.g. from client entry)
"/assets/entry.js", // same file from SSR manifest with leading slash
"/assets/framework.js",
];
const tags = simulateAssetTagFiltering(ssrFiles, []);
// entry.js should appear exactly once in modulepreload tags
const entryPreloads = tags.filter((t) => t.includes("entry.js") && t.includes("modulepreload"));
expect(entryPreloads).toHaveLength(1);
// framework.js should also appear with correct path
expect(tags).toContain('<link rel="modulepreload" href="/assets/framework.js" />');
});
});