Add test for isNavigatingToNewRootLayout

packages/next/src/client/components/router-reducer/is-navigating-to-new-root-layout.ts.test.ts

@@ -0,0 +1,100 @@
+import type { FlightRouterState } from '../../../server/app-render'
+import { isNavigatingToNewRootLayout } from './is-navigating-to-new-root-layout'
+
+describe('shouldHardNavigate', () => {
+  it('should return false if there is no new root layout', () => {
+    const getInitialRouterStateTree = (): FlightRouterState => [
+      '',
+      {
+        children: [
+          'linking',
+          {
+            children: ['', {}],
+          },
+        ],
+      },
+      undefined,
+      undefined,
+      true,
+    ]
+    const initialRouterStateTree = getInitialRouterStateTree()
+    const getNewRouterStateTree = (): FlightRouterState => {
+      return [
+        '',
+        {
+          children: [
+            'link-hard-push',
+            {
+              children: [
+                ['id', '456', 'd'],
+                {
+                  children: ['', {}],
+                },
+              ],
+            },
+          ],
+        },
+        null,
+        null,
+        true,
+      ]
+    }
+    const newRouterState = getNewRouterStateTree()
+
+    const result = isNavigatingToNewRootLayout(
+      newRouterState,
+      initialRouterStateTree
+    )
+
+    expect(result).toBe(false)
+  })
+
+  it('should return true if there is a mismatch between the root layouts', () => {
+    const getInitialRouterStateTree = (): FlightRouterState => [
+      '',
+      {
+        children: [
+          'linking',
+          {
+            children: ['', {}],
+          },
+          undefined,
+          undefined,
+          // Root layout at `linking` level.
+          true,
+        ],
+      },
+    ]
+    const initialRouterStateTree = getInitialRouterStateTree()
+    const getNewRouterStateTree = (): FlightRouterState => {
+      return [
+        '',
+        {
+          children: [
+            'link-hard-push',
+            {
+              children: [
+                ['id', '456', 'd'],
+                {
+                  children: ['', {}],
+                },
+              ],
+            },
+            null,
+            null,
+            // Root layout at `link-hard-push` level.
+            true,
+          ],
+        },
+      ]
+    }
+    const newRouterState = getNewRouterStateTree()
+
+    const result = isNavigatingToNewRootLayout(
+      newRouterState,
+      initialRouterStateTree
+    )
+
+    expect(result).toBe(true)
+  })
+})