Add shared dynamic api (#39163)

Add `next/dist/client/components/shared/dynamic` as shared api which server and client components can both support. 
Dynamic imports will be part of flight on server side.
This pr doesn't contain preloading part for client components.

packages/next/client/components/shared/dynamic/index.tsx

@@ -0,0 +1,21 @@
+import React from 'react'
+
+export type LoaderComponent<P = {}> = Promise<{
+  default: React.ComponentType<P>
+}>
+
+export type Loader<P = {}> = () => LoaderComponent<P>
+
+export type DynamicOptions<P = {}> = {
+  loader?: Loader<P>
+}
+
+export type LoadableComponent<P = {}> = React.ComponentType<P>
+
+export default function dynamic<P = {}>(
+  loader: Loader<P>
+): React.ComponentType<P> {
+  const LazyLoadable = React.lazy(loader)
+
+  return LazyLoadable
+}

test/e2e/app-dir/app/app/dashboard/index/dynamic-imports/dynamic.client.js

@@ -0,0 +1,7 @@
+import dynamic from 'next/dist/client/components/shared/dynamic'
+
+const Dynamic = dynamic(() => import('../text-dynamic.client'))
+
+export function NextDynamicClientComponent() {
+  return <Dynamic />
+}

test/e2e/app-dir/app/app/dashboard/index/dynamic-imports/dynamic.server.js

@@ -0,0 +1,7 @@
+import dynamic from 'next/dist/client/components/shared/dynamic'
+
+const Dynamic = dynamic(() => import('../text-dynamic.server'))
+
+export function NextDynamicServerComponent() {
+  return <Dynamic />
+}

test/e2e/app-dir/app/app/dashboard/index/react-lazy.client.js → test/e2e/app-dir/app/app/dashboard/index/dynamic-imports/react-lazy.client.js

@@ -1,13 +1,13 @@
 import { useState, lazy } from 'react'
 
-const Lazy = lazy(() => import('./lazy.client.js'))
+const Lazy = lazy(() => import('../text-lazy.client.js'))
 
 export function LazyClientComponent() {
   let [state] = useState('client')
   return (
     <>
       <Lazy />
-      <p className="hi">hello from modern the {state}</p>
+      <p className="hi">hello from {state}</p>
     </>
   )
 }

test/e2e/app-dir/app/app/dashboard/index/page.server.js

@@ -1,10 +1,12 @@
-import { LazyClientComponent } from './react-lazy.client'
-import { NextDynamicClientComponent } from './next-dynamic.client'
+import { LazyClientComponent } from './dynamic-imports/react-lazy.client'
+import { NextDynamicServerComponent } from './dynamic-imports/dynamic.server'
+import { NextDynamicClientComponent } from './dynamic-imports/dynamic.client'
 
 export default function DashboardIndexPage() {
   return (
     <>
       <p>hello from app/dashboard/index</p>
+      <NextDynamicServerComponent />
       <NextDynamicClientComponent />
       <LazyClientComponent />
     </>

test/e2e/app-dir/app/app/dashboard/index/text-dynamic.client.js

@@ -0,0 +1,11 @@
+import { useState } from 'react'
+import styles from './dynamic.module.css'
+
+export default function Dynamic() {
+  let [state] = useState('dynamic on client')
+  return (
+    <p id="css-text-dynamic-client" className={styles.dynamic}>
+      {`hello from ${state}`}
+    </p>
+  )
+}

test/e2e/app-dir/app/app/dashboard/index/text-dynamic.server.js

@@ -0,0 +1,9 @@
+import styles from './dynamic.module.css'
+
+export default function Dynamic() {
+  return (
+    <p id="css-text-dynamic-server" className={styles.dynamic}>
+      hello from dynamic on server
+    </p>
+  )
+}

test/e2e/app-dir/index.test.ts

@@ -67,8 +67,11 @@ describe('app dir', () => {
   it('should serve /index as separate page', async () => {
     const html = await renderViaHTTP(next.url, '/dashboard/index')
     expect(html).toContain('hello from app/dashboard/index')
-    // should load chunks generated via async import correctly
+    // should load chunks generated via async import correctly with React.lazy
     expect(html).toContain('hello from lazy')
+    // should support `dynamic` in both server and client components
+    expect(html).toContain('hello from dynamic on server')
+    expect(html).toContain('hello from dynamic on client')
   })
 
   // TODO-APP: handle css modules fouc in dev
@@ -77,7 +80,7 @@ describe('app dir', () => {
 
     expect(
       await browser.eval(
-        `window.getComputedStyle(document.querySelector('#css-text-dynamic')).color`
+        `window.getComputedStyle(document.querySelector('#css-text-dynamic-server')).color`
       )
     ).toBe('rgb(0, 0, 255)')
     expect(