Fix SWC dynamic transform with suspense but without ssr

Author: Brooooooklyn

packages/next-swc/crates/core/src/next_dynamic.rs

@@ -226,6 +226,7 @@ impl Fold for NextDynamicPatcher {
                         })))];
 
                     let mut has_ssr_false = false;
+                    let mut has_suspense = false;
 
                     if expr.args.len() == 2 {
                         if let Expr::Object(ObjectLit {
@@ -253,21 +254,29 @@ impl Fold for NextDynamicPatcher {
                                             if let Some(Lit::Bool(Bool {
                                                 value: false,
                                                 span: _,
-                                            })) = match &**value {
-                                                Expr::Lit(lit) => Some(lit),
-                                                _ => None,
-                                            } {
+                                            })) = value.as_lit()
+                                            {
                                                 has_ssr_false = true
                                             }
                                         }
+                                        if sym == "suspense" {
+                                            if let Some(Lit::Bool(Bool {
+                                                value: true,
+                                                span: _,
+                                            })) = value.as_lit()
+                                            {
+                                                has_suspense = true
+                                            }
+                                        }
                                     }
                                 }
                             }
                             props.extend(options_props.iter().cloned());
                         }
                     }
-
-                    if has_ssr_false && self.is_server {
+                    // Don't need to strip the `loader` argument if suspense is true
+                    // See https://github.com/vercel/next.js/issues/36636 for background
+                    if has_ssr_false && !has_suspense && self.is_server {
                         expr.args[0] = Lit::Null(Null { span: DUMMY_SP }).as_arg();
                     }
 

packages/next-swc/crates/core/tests/fixture/next-dynamic/with-options/input.js

@@ -9,3 +9,8 @@ const DynamicClientOnlyComponent = dynamic(
   () => import('../components/hello'),
   { ssr: false }
 )
+
+const DynamicClientOnlyComponentWithSuspense = dynamic(
+  () => import('../components/hello'),
+  { ssr: false, suspense: true }
+)

packages/next-swc/crates/core/tests/fixture/next-dynamic/with-options/output-dev.js

@@ -17,3 +17,13 @@ const DynamicClientOnlyComponent = dynamic(()=>import('../components/hello')
     },
     ssr: false
 });
+const DynamicClientOnlyComponentWithSuspense = dynamic(()=>import('../components/hello')
+, {
+    loadableGenerated: {
+        modules: [
+            "some-file.js -> " + "../components/hello"
+        ]
+    },
+    ssr: false,
+    suspense: true
+});

packages/next-swc/crates/core/tests/fixture/next-dynamic/with-options/output-prod.js

@@ -17,3 +17,13 @@ const DynamicClientOnlyComponent = dynamic(()=>import('../components/hello')
     },
     ssr: false
 });
+const DynamicClientOnlyComponentWithSuspense = dynamic(()=>import('../components/hello')
+, {
+    loadableGenerated: {
+        webpack: ()=>[
+                require.resolveWeak("../components/hello")
+            ]
+    },
+    ssr: false,
+    suspense: true
+});

packages/next-swc/crates/core/tests/fixture/next-dynamic/with-options/output-server.js

@@ -16,3 +16,13 @@ const DynamicClientOnlyComponent = dynamic(null, {
     },
     ssr: false
 });
+const DynamicClientOnlyComponentWithSuspense = dynamic(()=>import('../components/hello')
+, {
+    loadableGenerated: {
+        modules: [
+            "some-file.js -> " + "../components/hello"
+        ]
+    },
+    ssr: false,
+    suspense: true
+});

test/e2e/dynamic-with-suspense/index.test.ts

@@ -0,0 +1,55 @@
+import { createNext } from 'e2e-utils'
+import { NextInstance } from 'test/lib/next-modes/base'
+import { hasRedbox, renderViaHTTP } from 'next-test-utils'
+import webdriver from 'next-webdriver'
+
+const suite =
+  process.env.NEXT_TEST_REACT_VERSION === '^17' ? describe.skip : describe
+
+// Skip the suspense test if react version is 17
+suite('dynamic with suspense', () => {
+  let next: NextInstance
+
+  beforeAll(async () => {
+    next = await createNext({
+      files: {
+        'pages/index.js': `
+          import { Suspense } from "react";
+          import dynamic from "next/dynamic";
+          
+          const Thing = dynamic(() => import("./thing"), { ssr: false, suspense: true });
+          
+          export default function IndexPage() {
+            return (
+              <div>
+                <p>Next.js Example</p>
+                <Suspense fallback="Loading...">
+                  <Thing />
+                </Suspense>
+              </div>
+            );
+          }
+        `,
+        'pages/thing.js': `
+          export default function Thing() {
+            return "Thing";
+          }
+        `,
+      },
+      dependencies: {},
+    })
+  })
+  afterAll(() => next.destroy())
+
+  it('should render server-side', async () => {
+    const html = await renderViaHTTP(next.url, '/')
+    expect(html).toContain('Next.js Example')
+    expect(html).toContain('Thing')
+  })
+
+  it('should render client-side', async () => {
+    const browser = await webdriver(next.url, '/')
+    expect(await hasRedbox(browser)).toBe(false)
+    await browser.close()
+  })
+})