presets(vercel): support node.js 26

docs/2.deploy/20.providers/vercel.md

@@ -40,6 +40,8 @@ Nitro checks these sources, in order, to pick the runtime of the server function
 3. `bunVersion` in `vercel.json`.
 4. The runtime running the build: Bun when building with Bun, otherwise the build's Node.js major version, clamped to the versions Vercel supports.
 
+Vercel supports Node.js 22, 24, and 26. A build on Node.js 23 or 25 uses the next supported version, and a build on a newer version uses `26`.
+
 Steps 2 and 3 follow the same precedence as Vercel.
 
 ```json [package.json]

src/presets/vercel/types.ts

@@ -106,7 +106,7 @@ export interface VercelServerlessFunctionConfig {
   /**
    * The runtime to use. Defaults to `engines` in `package.json`, then `bunVersion` in `vercel.json`, then the runtime used to build.
    */
-  runtime?: "nodejs22.x" | "nodejs24.x" | "bun1.x" | "bun1.4.x" | (string & {});
+  runtime?: "nodejs22.x" | "nodejs24.x" | "nodejs26.x" | "bun1.x" | "bun1.4.x" | (string & {});
 
   /**
    * Experimental trigger configuration (e.g., Vercel Queues).

src/presets/vercel/utils.ts

@@ -34,7 +34,8 @@ import { ISR_URL_PARAM } from "./runtime/isr.ts";
 // https://vercel.com/docs/build-output-api/configuration
 
 // https://vercel.com/docs/functions/runtimes/node-js/node-js-versions
-const SUPPORTED_NODE_VERSIONS = [22, 24];
+// https://github.com/vercel/vercel/blob/main/packages/build-utils/src/fs/node-version.ts
+const SUPPORTED_NODE_VERSIONS = [22, 24, 26];
 
 // h3 ProxyOptions that Vercel CDN rewrites cannot handle at the edge.
 // https://vercel.com/docs/rewrites

test/unit/vercel-runtime.test.ts

@@ -14,10 +14,12 @@ describe("vercel: resolveVercelRuntime", () => {
   beforeEach(async () => {
     rootDir = await realpath(await mkdtemp(join(tmpdir(), "nitro-vercel-runtime-")));
     warn = vi.fn();
+    stubNodeVersion("26.0.0");
   });
 
   afterEach(async () => {
     vi.unstubAllGlobals();
+    restoreNodeVersion();
     await rm(rootDir, { recursive: true, force: true });
   });
 
@@ -51,9 +53,10 @@ describe("vercel: resolveVercelRuntime", () => {
     ["22.x", "nodejs22.x"],
     ["^22", "nodejs22.x"],
     [">=20 <24", "nodejs22.x"],
-    [">=22.0.0", "nodejs24.x"],
+    ["26.x", "nodejs26.x"],
+    [">=22.0.0", "nodejs26.x"],
     [">=24.20.0 <25", "nodejs24.x"],
-    ["^20.19.0 || >=22.12.0", "nodejs24.x"],
+    ["^20.19.0 || >=22.12.0", "nodejs26.x"],
   ])(
     "uses the newest supported Node.js version matching engines.node %s",
     async (node, expected) => {
@@ -62,6 +65,34 @@ describe("vercel: resolveVercelRuntime", () => {
     }
   );
 
+  it.skipIf(isBun).each([
+    ["26.0.0", "nodejs26.x"],
+    ["24.1.0", "nodejs24.x"],
+    ["22.0.0", "nodejs22.x"],
+    ["20.0.0", "nodejs22.x"],
+    ["23.0.0", "nodejs24.x"],
+    ["25.0.0", "nodejs26.x"],
+    ["27.0.0", "nodejs26.x"],
+    ["30.2.1", "nodejs26.x"],
+  ])("uses the runtime for the build Node.js version %s", async (version, expected) => {
+    stubNodeVersion(version);
+    expect(await resolveRuntime()).toBe(expected);
+    expect(warn).not.toHaveBeenCalled();
+  });
+
+  it("accepts an explicit nodejs26.x runtime", async () => {
+    stubNodeVersion("24.0.0");
+    expect(await resolveRuntime({ runtime: "nodejs26.x" })).toBe("nodejs26.x");
+  });
+
+  it("does not select versions newer than 26 when building on them", async () => {
+    stubNodeVersion("28.0.0");
+    expect(await resolveRuntime({ engines: { node: ">=22" } })).toBe("nodejs26.x");
+    expect(warn).not.toHaveBeenCalled();
+    expect(await resolveRuntime({ engines: { node: "28.x" } })).toBe("nodejs26.x");
+    expect(warn).toHaveBeenCalledWith(expect.stringContaining("(22, 24, 26)"));
+  });
+
   it("uses engines.node when building with Bun", async () => {
     stubBun();
     expect(await resolveRuntime({ engines: { node: ">=24.20.0 <25" } })).toBe("nodejs24.x");
@@ -128,7 +159,7 @@ describe("vercel: resolveVercelRuntime", () => {
     expect(await resolveRuntime()).toBe("bun1.x");
   });
 
-  it.each(["20.x", "18.x", ">=26", "lts/*"])(
+  it.each(["20.x", "18.x", ">=28", "lts/*"])(
     "warns and uses the build Node.js version when engines.node %s matches no supported version",
     async (node) => {
       const fallback = await resolveRuntime({ engines: { node } });
@@ -193,6 +224,16 @@ describe("vercel preset: function runtime from engines", () => {
   });
 });
 
+const originalNodeVersion = Object.getOwnPropertyDescriptor(process.versions, "node")!;
+
+function stubNodeVersion(version: string) {
+  Object.defineProperty(process.versions, "node", { ...originalNodeVersion, value: version });
+}
+
+function restoreNodeVersion() {
+  Object.defineProperty(process.versions, "node", originalNodeVersion);
+}
+
 // `Bun` is a non-configurable global on Bun
 function stubBun() {
   if (!isBun) {