Refactored header title component

src/assets/javascripts/components/header/_/index.ts

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2016-2020 Martin Donath <martin.donath@squidfunk.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+import { OperatorFunction, pipe } from "rxjs"
+import { shareReplay, switchMap } from "rxjs/operators"
+
+import { Header, watchHeader } from "observables"
+
+/* ----------------------------------------------------------------------------
+ * Functions
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Mount header from source observable
+ *
+ * @return Header observable
+ */
+export function mountHeader(): OperatorFunction<HTMLElement, Header> {
+  return pipe(
+    switchMap(watchHeader),
+    shareReplay(1)
+  )
+}

src/assets/javascripts/components/header/index.ts

@@ -20,23 +20,5 @@
  * IN THE SOFTWARE.
  */
 
-import { OperatorFunction, pipe } from "rxjs"
-import { shareReplay, switchMap } from "rxjs/operators"
-
-import { Header, watchHeader } from "observables"
-
-/* ----------------------------------------------------------------------------
- * Functions
- * ------------------------------------------------------------------------- */
-
-/**
- * Mount header from source observable
- *
- * @return Header observable
- */
-export function mountHeader(): OperatorFunction<HTMLElement, Header> {
-  return pipe(
-    switchMap(watchHeader),
-    shareReplay(1)
-  )
-}
+export * from "./_"
+export * from "./title"

src/assets/javascripts/components/header/title/index.ts

@@ -0,0 +1,75 @@
+/*
+ * Copyright (c) 2016-2020 Martin Donath <martin.donath@squidfunk.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+import { Observable, OperatorFunction, pipe } from "rxjs"
+import { map, switchMap } from "rxjs/operators"
+
+import {
+  Header,
+  Viewport,
+  getElementOrThrow,
+  paintHeaderTitle,
+  watchViewportAt
+} from "observables"
+
+import { useComponent } from "../../_"
+
+/* ----------------------------------------------------------------------------
+ * Helper types
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Mount options
+ */
+interface MountOptions {
+  header$: Observable<Header>          /* Header observable */
+  viewport$: Observable<Viewport>      /* Viewport observable */
+}
+
+/* ----------------------------------------------------------------------------
+ * Functions
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Mount header title from source observable
+ *
+ * @param options - Options
+ *
+ * @return Header title observable
+ */
+export function mountHeaderTitle(
+  { header$, viewport$ }: MountOptions
+): OperatorFunction<HTMLElement, any> {
+  return pipe(
+    switchMap(el => useComponent("main")
+      .pipe(
+        map(main => getElementOrThrow("h1, h2, h3, h4, h5, h6", main)),
+        switchMap(headline => watchViewportAt(headline, { header$, viewport$ })
+          .pipe(
+            map(({ offset: { y } }) => y >= headline.offsetHeight),
+            paintHeaderTitle(el)
+          )
+        )
+      )
+    )
+  )
+}