fix ScopedHistory.createHref to prepend location with scoped history basePath

docs/development/core/public/kibana-plugin-core-public.scopedhistory.createhref.md

@@ -4,10 +4,12 @@
 
 ## ScopedHistory.createHref property
 
-Creates an href (string) to the location.
+Creates an href (string) to the location. If `prependBasePath` is true (default), it will prepend the location's path with the scoped history basePath.
 
 <b>Signature:</b>
 
 ```typescript
-createHref: (location: LocationDescriptorObject<HistoryLocationState>) => string;
+createHref: (location: LocationDescriptorObject<HistoryLocationState>, { prependBasePath }?: {
+        prependBasePath?: boolean | undefined;
+    }) => string;
 ```

docs/development/core/public/kibana-plugin-core-public.scopedhistory.md

@@ -28,7 +28,7 @@ export declare class ScopedHistory<HistoryLocationState = unknown> implements Hi
 |  --- | --- | --- | --- |
 |  [action](./kibana-plugin-core-public.scopedhistory.action.md) |  | <code>Action</code> | The last action dispatched on the history stack. |
 |  [block](./kibana-plugin-core-public.scopedhistory.block.md) |  | <code>(prompt?: string &#124; boolean &#124; History.TransitionPromptHook&lt;HistoryLocationState&gt; &#124; undefined) =&gt; UnregisterCallback</code> | Not supported. Use [AppMountParameters.onAppLeave](./kibana-plugin-core-public.appmountparameters.onappleave.md)<!-- -->. |
-|  [createHref](./kibana-plugin-core-public.scopedhistory.createhref.md) |  | <code>(location: LocationDescriptorObject&lt;HistoryLocationState&gt;) =&gt; string</code> | Creates an href (string) to the location. |
+|  [createHref](./kibana-plugin-core-public.scopedhistory.createhref.md) |  | <code>(location: LocationDescriptorObject&lt;HistoryLocationState&gt;, { prependBasePath }?: {</code><br/><code>        prependBasePath?: boolean &#124; undefined;</code><br/><code>    }) =&gt; string</code> | Creates an href (string) to the location. If <code>prependBasePath</code> is true (default), it will prepend the location's path with the scoped history basePath. |
 |  [createSubHistory](./kibana-plugin-core-public.scopedhistory.createsubhistory.md) |  | <code>&lt;SubHistoryLocationState = unknown&gt;(basePath: string) =&gt; ScopedHistory&lt;SubHistoryLocationState&gt;</code> | Creates a <code>ScopedHistory</code> for a subpath of this <code>ScopedHistory</code>. Useful for applications that may have sub-apps that do not need access to the containing application's history. |
 |  [go](./kibana-plugin-core-public.scopedhistory.go.md) |  | <code>(n: number) =&gt; void</code> | Send the user forward or backwards in the history stack. |
 |  [goBack](./kibana-plugin-core-public.scopedhistory.goback.md) |  | <code>() =&gt; void</code> | Send the user one location back in the history stack. Equivalent to calling [ScopedHistory.go(-1)](./kibana-plugin-core-public.scopedhistory.go.md)<!-- -->. If no more entries are available backwards, this is a no-op. |

src/core/public/application/scoped_history.test.ts

@@ -268,11 +268,32 @@ describe('ScopedHistory', () => {
       const gh = createMemoryHistory();
       gh.push('/app/wow');
       const h = new ScopedHistory(gh, '/app/wow');
-      expect(h.createHref({ pathname: '' })).toEqual(`/`);
+      expect(h.createHref({ pathname: '' })).toEqual(`/app/wow`);
+      expect(h.createHref({})).toEqual(`/app/wow`);
       expect(h.createHref({ pathname: '/new-page', search: '?alpha=true' })).toEqual(
-        `/new-page?alpha=true`
+        `/app/wow/new-page?alpha=true`
       );
     });
+
+    it('behave correctly with slash-ending basePath', () => {
+      const gh = createMemoryHistory();
+      gh.push('/app/wow/');
+      const h = new ScopedHistory(gh, '/app/wow/');
+      expect(h.createHref({ pathname: '' })).toEqual(`/app/wow/`);
+      expect(h.createHref({ pathname: '/new-page', search: '?alpha=true' })).toEqual(
+        `/app/wow/new-page?alpha=true`
+      );
+    });
+
+    it('skips the scoped history path when `prependBasePath` is false', () => {
+      const gh = createMemoryHistory();
+      gh.push('/app/wow');
+      const h = new ScopedHistory(gh, '/app/wow');
+      expect(h.createHref({ pathname: '' }, { prependBasePath: false })).toEqual(`/`);
+      expect(
+        h.createHref({ pathname: '/new-page', search: '?alpha=true' }, { prependBasePath: false })
+      ).toEqual(`/new-page?alpha=true`);
+    });
   });
 
   describe('action', () => {

src/core/public/application/scoped_history.ts

@@ -219,11 +219,26 @@ export class ScopedHistory<HistoryLocationState = unknown>
 
   /**
    * Creates an href (string) to the location.
+   * If `prependBasePath` is true (default), it will prepend the location's path with the scoped history basePath.
    *
    * @param location
+   * @param prependBasePath
    */
-  public createHref = (location: LocationDescriptorObject<HistoryLocationState>): Href => {
+  public createHref = (
+    location: LocationDescriptorObject<HistoryLocationState>,
+    { prependBasePath = true }: { prependBasePath?: boolean } = {}
+  ): Href => {
     this.verifyActive();
+    if (prependBasePath) {
+      location = this.prependBasePath(location);
+      if (location.pathname === undefined) {
+        // we always want to create an url relative to the basePath
+        // so if pathname is not present, we use the history's basePath as default
+        // we are doing that here because `prependBasePath` should not
+        // alter pathname for other method calls
+        location.pathname = this.basePath;
+      }
+    }
     return this.parentHistory.createHref(location);
   };
 
@@ -254,8 +269,7 @@ export class ScopedHistory<HistoryLocationState = unknown>
    * Prepends the base path to string.
    */
   private prependBasePathToString(path: string): string {
-    path = path.startsWith('/') ? path.slice(1) : path;
-    return path.length ? `${this.basePath}/${path}` : this.basePath;
+    return path.length ? `${this.basePath}/${path}`.replace(/\/{2,}/g, '/') : this.basePath;
   }
 
   /**

src/core/public/public.api.md

@@ -1196,7 +1196,9 @@ export class ScopedHistory<HistoryLocationState = unknown> implements History<Hi
     constructor(parentHistory: History, basePath: string);
     get action(): Action;
     block: (prompt?: string | boolean | History.TransitionPromptHook<HistoryLocationState> | undefined) => UnregisterCallback;
-    createHref: (location: LocationDescriptorObject<HistoryLocationState>) => string;
+    createHref: (location: LocationDescriptorObject<HistoryLocationState>, { prependBasePath }?: {
+        prependBasePath?: boolean | undefined;
+    }) => string;
     createSubHistory: <SubHistoryLocationState = unknown>(basePath: string) => ScopedHistory<SubHistoryLocationState>;
     go: (n: number) => void;
     goBack: () => void;

test/plugin_functional/plugins/core_plugin_a/public/application.tsx

@@ -95,7 +95,7 @@ const Nav = withRouter(({ history, navigateToApp }: NavProps) => (
           {
             id: 'home',
             name: 'Home',
-            onClick: () => history.push('/'),
+            onClick: () => history.push(''),
             'data-test-subj': 'fooNavHome',
           },
           {

test/plugin_functional/plugins/core_plugin_b/public/application.tsx

@@ -102,7 +102,7 @@ const Nav = withRouter(({ history, navigateToApp }: NavProps) => (
           {
             id: 'home',
             name: 'Home',
-            onClick: () => navigateToApp('bar', { path: '/' }),
+            onClick: () => navigateToApp('bar', { path: '' }),
             'data-test-subj': 'barNavHome',
           },
           {