feat(version): versions

1 files changed, 84 insertions, 0 deletions

diff --git a/src/templates/assets/javascripts/browser/viewport/at/index.ts b/src/templates/assets/javascripts/browser/viewport/at/index.ts
new file mode 100644
index 00000000..8769cf3b
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/viewport/at/index.ts
@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2016-2023 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,
+  combineLatest,
+  distinctUntilKeyChanged,
+  map
+} from "rxjs"
+
+import { Header } from "~/components"
+
+import { getElementOffset } from "../../element"
+import { Viewport } from "../_"
+
+/* ----------------------------------------------------------------------------
+ * Helper types
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Watch options
+ */
+interface WatchOptions {
+  viewport$: Observable<Viewport>      /* Viewport observable */
+  header$: Observable<Header>          /* Header observable */
+}
+
+/* ----------------------------------------------------------------------------
+ * Functions
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Watch viewport relative to element
+ *
+ * @param el - Element
+ * @param options - Options
+ *
+ * @returns Viewport observable
+ */
+export function watchViewportAt(
+  el: HTMLElement, { viewport$, header$ }: WatchOptions
+): Observable<Viewport> {
+  const size$ = viewport$
+    .pipe(
+      distinctUntilKeyChanged("size")
+    )
+
+  /* Compute element offset */
+  const offset$ = combineLatest([size$, header$])
+    .pipe(
+      map(() => getElementOffset(el))
+    )
+
+  /* Compute relative viewport, return hot observable */
+  return combineLatest([header$, viewport$, offset$])
+    .pipe(
+      map(([{ height }, { offset, size }, { x, y }]) => ({
+        offset: {
+          x: offset.x - x,
+          y: offset.y - y + height
+        },
+        size
+      }))
+    )
+}