feat(version): versions

27 files changed, 2082 insertions, 0 deletions

diff --git a/src/templates/assets/javascripts/browser/document/index.ts b/src/templates/assets/javascripts/browser/document/index.ts
new file mode 100644
index 00000000..354c9b5c
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/document/index.ts
@@ -0,0 +1,48 @@
+/*
+ * 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 {
+  ReplaySubject,
+  Subject,
+  fromEvent
+} from "rxjs"
+
+/* ----------------------------------------------------------------------------
+ * Functions
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Watch document
+ *
+ * Documents are implemented as subjects, so all downstream observables are
+ * automatically updated when a new document is emitted.
+ *
+ * @returns Document subject
+ */
+export function watchDocument(): Subject<Document> {
+  const document$ = new ReplaySubject<Document>(1)
+  fromEvent(document, "DOMContentLoaded", { once: true })
+    .subscribe(() => document$.next(document))
+
+  /* Return document */
+  return document$
+}
diff --git a/src/templates/assets/javascripts/browser/element/_/.eslintrc b/src/templates/assets/javascripts/browser/element/_/.eslintrc
new file mode 100644
index 00000000..16973760
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/element/_/.eslintrc
@@ -0,0 +1,6 @@
+{
+  "rules": {
+    "jsdoc/require-jsdoc": "off",
+    "jsdoc/require-returns-check": "off"
+  }
+}
diff --git a/src/templates/assets/javascripts/browser/element/_/index.ts b/src/templates/assets/javascripts/browser/element/_/index.ts
new file mode 100644
index 00000000..b7beb462
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/element/_/index.ts
@@ -0,0 +1,120 @@
+/*
+ * 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.
+ */
+
+/* ----------------------------------------------------------------------------
+ * Functions
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Retrieve all elements matching the query selector
+ *
+ * @template T - Element type
+ *
+ * @param selector - Query selector
+ * @param node - Node of reference
+ *
+ * @returns Elements
+ */
+export function getElements<T extends keyof HTMLElementTagNameMap>(
+  selector: T, node?: ParentNode
+): HTMLElementTagNameMap[T][]
+
+export function getElements<T extends HTMLElement>(
+  selector: string, node?: ParentNode
+): T[]
+
+export function getElements<T extends HTMLElement>(
+  selector: string, node: ParentNode = document
+): T[] {
+  return Array.from(node.querySelectorAll<T>(selector))
+}
+
+/**
+ * Retrieve an element matching a query selector or throw a reference error
+ *
+ * Note that this function assumes that the element is present. If unsure if an
+ * element is existent, use the `getOptionalElement` function instead.
+ *
+ * @template T - Element type
+ *
+ * @param selector - Query selector
+ * @param node - Node of reference
+ *
+ * @returns Element
+ */
+export function getElement<T extends keyof HTMLElementTagNameMap>(
+  selector: T, node?: ParentNode
+): HTMLElementTagNameMap[T]
+
+export function getElement<T extends HTMLElement>(
+  selector: string, node?: ParentNode
+): T
+
+export function getElement<T extends HTMLElement>(
+  selector: string, node: ParentNode = document
+): T {
+  const el = getOptionalElement<T>(selector, node)
+  if (typeof el === "undefined")
+    throw new ReferenceError(
+      `Missing element: expected "${selector}" to be present`
+    )
+
+  /* Return element */
+  return el
+}
+
+/* ------------------------------------------------------------------------- */
+
+/**
+ * Retrieve an optional element matching the query selector
+ *
+ * @template T - Element type
+ *
+ * @param selector - Query selector
+ * @param node - Node of reference
+ *
+ * @returns Element or nothing
+ */
+export function getOptionalElement<T extends keyof HTMLElementTagNameMap>(
+  selector: T, node?: ParentNode
+): HTMLElementTagNameMap[T] | undefined
+
+export function getOptionalElement<T extends HTMLElement>(
+  selector: string, node?: ParentNode
+): T | undefined
+
+export function getOptionalElement<T extends HTMLElement>(
+  selector: string, node: ParentNode = document
+): T | undefined {
+  return node.querySelector<T>(selector) || undefined
+}
+
+/**
+ * Retrieve the currently active element
+ *
+ * @returns Element or nothing
+ */
+export function getActiveElement(): HTMLElement | undefined {
+  return document.activeElement instanceof HTMLElement
+    ? document.activeElement || undefined
+    : undefined
+}
diff --git a/src/templates/assets/javascripts/browser/element/focus/index.ts b/src/templates/assets/javascripts/browser/element/focus/index.ts
new file mode 100644
index 00000000..f31fe276
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/element/focus/index.ts
@@ -0,0 +1,81 @@
+/*
+ * 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,
+  debounceTime,
+  distinctUntilChanged,
+  fromEvent,
+  map,
+  merge,
+  shareReplay,
+  startWith
+} from "rxjs"
+
+import { getActiveElement } from "../_"
+
+/* ----------------------------------------------------------------------------
+ * Data
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Focus observable
+ *
+ * Previously, this observer used `focus` and `blur` events to determine whether
+ * an element is focused, but this doesn't work if there are focusable elements
+ * within the elements itself. A better solutions are `focusin` and `focusout`
+ * events, which bubble up the tree and allow for more fine-grained control.
+ *
+ * `debounceTime` is necessary, because when a focus change happens inside an
+ * element, the observable would first emit `false` and then `true` again.
+ */
+const observer$ = merge(
+  fromEvent(document.body, "focusin"),
+  fromEvent(document.body, "focusout")
+)
+  .pipe(
+    debounceTime(1),
+    startWith(undefined),
+    map(() => getActiveElement() || document.body),
+    shareReplay(1)
+  )
+
+/* ----------------------------------------------------------------------------
+ * Functions
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Watch element focus
+ *
+ * @param el - Element
+ *
+ * @returns Element focus observable
+ */
+export function watchElementFocus(
+  el: HTMLElement
+): Observable<boolean> {
+  return observer$
+    .pipe(
+      map(active => el.contains(active)),
+      distinctUntilChanged()
+    )
+}
diff --git a/src/templates/assets/javascripts/browser/element/index.ts b/src/templates/assets/javascripts/browser/element/index.ts
new file mode 100644
index 00000000..50ce84b2
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/element/index.ts
@@ -0,0 +1,27 @@
+/*
+ * 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.
+ */
+
+export * from "./_"
+export * from "./focus"
+export * from "./offset"
+export * from "./size"
+export * from "./visibility"
diff --git a/src/templates/assets/javascripts/browser/element/offset/_/index.ts b/src/templates/assets/javascripts/browser/element/offset/_/index.ts
new file mode 100644
index 00000000..6dd229d5
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/element/offset/_/index.ts
@@ -0,0 +1,86 @@
+/*
+ * 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,
+  animationFrameScheduler,
+  auditTime,
+  fromEvent,
+  map,
+  merge,
+  startWith
+} from "rxjs"
+
+/* ----------------------------------------------------------------------------
+ * Types
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Element offset
+ */
+export interface ElementOffset {
+  x: number                            /* Horizontal offset */
+  y: number                            /* Vertical offset */
+}
+
+/* ----------------------------------------------------------------------------
+ * Functions
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Retrieve element offset
+ *
+ * @param el - Element
+ *
+ * @returns Element offset
+ */
+export function getElementOffset(
+  el: HTMLElement
+): ElementOffset {
+  return {
+    x: el.offsetLeft,
+    y: el.offsetTop
+  }
+}
+
+/* ------------------------------------------------------------------------- */
+
+/**
+ * Watch element offset
+ *
+ * @param el - Element
+ *
+ * @returns Element offset observable
+ */
+export function watchElementOffset(
+  el: HTMLElement
+): Observable<ElementOffset> {
+  return merge(
+    fromEvent(window, "load"),
+    fromEvent(window, "resize")
+  )
+    .pipe(
+      auditTime(0, animationFrameScheduler),
+      map(() => getElementOffset(el)),
+      startWith(getElementOffset(el))
+    )
+}
diff --git a/src/templates/assets/javascripts/browser/element/offset/content/index.ts b/src/templates/assets/javascripts/browser/element/offset/content/index.ts
new file mode 100644
index 00000000..557301a6
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/element/offset/content/index.ts
@@ -0,0 +1,76 @@
+/*
+ * 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,
+  animationFrameScheduler,
+  auditTime,
+  fromEvent,
+  map,
+  merge,
+  startWith
+} from "rxjs"
+
+import { ElementOffset } from "../_"
+
+/* ----------------------------------------------------------------------------
+ * Functions
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Retrieve element content offset (= scroll offset)
+ *
+ * @param el - Element
+ *
+ * @returns Element content offset
+ */
+export function getElementContentOffset(
+  el: HTMLElement
+): ElementOffset {
+  return {
+    x: el.scrollLeft,
+    y: el.scrollTop
+  }
+}
+
+/* ------------------------------------------------------------------------- */
+
+/**
+ * Watch element content offset
+ *
+ * @param el - Element
+ *
+ * @returns Element content offset observable
+ */
+export function watchElementContentOffset(
+  el: HTMLElement
+): Observable<ElementOffset> {
+  return merge(
+    fromEvent(el, "scroll"),
+    fromEvent(window, "resize")
+  )
+    .pipe(
+      auditTime(0, animationFrameScheduler),
+      map(() => getElementContentOffset(el)),
+      startWith(getElementContentOffset(el))
+    )
+}
diff --git a/src/templates/assets/javascripts/browser/element/offset/index.ts b/src/templates/assets/javascripts/browser/element/offset/index.ts
new file mode 100644
index 00000000..602ff2cf
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/element/offset/index.ts
@@ -0,0 +1,24 @@
+/*
+ * 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.
+ */
+
+export * from "./_"
+export * from "./content"
diff --git a/src/templates/assets/javascripts/browser/element/size/_/index.ts b/src/templates/assets/javascripts/browser/element/size/_/index.ts
new file mode 100644
index 00000000..35a5e68b
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/element/size/_/index.ts
@@ -0,0 +1,151 @@
+/*
+ * 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 {
+  NEVER,
+  Observable,
+  Subject,
+  defer,
+  filter,
+  finalize,
+  map,
+  merge,
+  of,
+  shareReplay,
+  startWith,
+  switchMap,
+  tap
+} from "rxjs"
+
+import { watchScript } from "../../../script"
+
+/* ----------------------------------------------------------------------------
+ * Types
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Element offset
+ */
+export interface ElementSize {
+  width: number                        /* Element width */
+  height: number                       /* Element height */
+}
+
+/* ----------------------------------------------------------------------------
+ * Data
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Resize observer entry subject
+ */
+const entry$ = new Subject<ResizeObserverEntry>()
+
+/**
+ * Resize observer observable
+ *
+ * This observable will create a `ResizeObserver` on the first subscription
+ * and will automatically terminate it when there are no more subscribers.
+ * It's quite important to centralize observation in a single `ResizeObserver`,
+ * as the performance difference can be quite dramatic, as the link shows.
+ *
+ * If the browser doesn't have a `ResizeObserver` implementation available, a
+ * polyfill is automatically downloaded from unpkg.com. This is also compatible
+ * with the built-in privacy plugin, which will download the polyfill and put
+ * it alongside the built site for self-hosting.
+ *
+ * @see https://bit.ly/3iIYfEm - Google Groups on performance
+ */
+const observer$ = defer(() => (
+  typeof ResizeObserver === "undefined"
+    ? watchScript("https://unpkg.com/resize-observer-polyfill")
+    : of(undefined)
+))
+  .pipe(
+    map(() => new ResizeObserver(entries => {
+      for (const entry of entries)
+        entry$.next(entry)
+    })),
+    switchMap(observer => merge(NEVER, of(observer))
+      .pipe(
+        finalize(() => observer.disconnect())
+      )
+    ),
+    shareReplay(1)
+  )
+
+/* ----------------------------------------------------------------------------
+ * Functions
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Retrieve element size
+ *
+ * @param el - Element
+ *
+ * @returns Element size
+ */
+export function getElementSize(
+  el: HTMLElement
+): ElementSize {
+  return {
+    width:  el.offsetWidth,
+    height: el.offsetHeight
+  }
+}
+
+/* ------------------------------------------------------------------------- */
+
+/**
+ * Watch element size
+ *
+ * This function returns an observable that subscribes to a single internal
+ * instance of `ResizeObserver` upon subscription, and emit resize events until
+ * termination. Note that this function should not be called with the same
+ * element twice, as the first unsubscription will terminate observation.
+ *
+ * Sadly, we can't use the `DOMRect` objects returned by the observer, because
+ * we need the emitted values to be consistent with `getElementSize`, which will
+ * return the used values (rounded) and not actual values (unrounded). Thus, we
+ * use the `offset*` properties. See the linked GitHub issue.
+ *
+ * @see https://bit.ly/3m0k3he - GitHub issue
+ *
+ * @param el - Element
+ *
+ * @returns Element size observable
+ */
+export function watchElementSize(
+  el: HTMLElement
+): Observable<ElementSize> {
+  return observer$
+    .pipe(
+      tap(observer => observer.observe(el)),
+      switchMap(observer => entry$
+        .pipe(
+          filter(({ target }) => target === el),
+          finalize(() => observer.unobserve(el)),
+          map(() => getElementSize(el))
+        )
+      ),
+      startWith(getElementSize(el))
+    )
+}
diff --git a/src/templates/assets/javascripts/browser/element/size/content/index.ts b/src/templates/assets/javascripts/browser/element/size/content/index.ts
new file mode 100644
index 00000000..5ed388cf
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/element/size/content/index.ts
@@ -0,0 +1,67 @@
+/*
+ * 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 { ElementSize } from "../_"
+
+/* ----------------------------------------------------------------------------
+ * Functions
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Retrieve element content size (= scroll width and height)
+ *
+ * @param el - Element
+ *
+ * @returns Element content size
+ */
+export function getElementContentSize(
+  el: HTMLElement
+): ElementSize {
+  return {
+    width:  el.scrollWidth,
+    height: el.scrollHeight
+  }
+}
+
+/**
+ * Retrieve the overflowing container of an element, if any
+ *
+ * @param el - Element
+ *
+ * @returns Overflowing container or nothing
+ */
+export function getElementContainer(
+  el: HTMLElement
+): HTMLElement | undefined {
+  let parent = el.parentElement
+  while (parent)
+    if (
+      el.scrollWidth  <= parent.scrollWidth &&
+      el.scrollHeight <= parent.scrollHeight
+    )
+      parent = (el = parent).parentElement
+    else
+      break
+
+  /* Return overflowing container */
+  return parent ? el : undefined
+}
diff --git a/src/templates/assets/javascripts/browser/element/size/index.ts b/src/templates/assets/javascripts/browser/element/size/index.ts
new file mode 100644
index 00000000..602ff2cf
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/element/size/index.ts
@@ -0,0 +1,24 @@
+/*
+ * 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.
+ */
+
+export * from "./_"
+export * from "./content"
diff --git a/src/templates/assets/javascripts/browser/element/visibility/index.ts b/src/templates/assets/javascripts/browser/element/visibility/index.ts
new file mode 100644
index 00000000..1ffe0b8d
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/element/visibility/index.ts
@@ -0,0 +1,131 @@
+/*
+ * 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 {
+  NEVER,
+  Observable,
+  Subject,
+  defer,
+  distinctUntilChanged,
+  filter,
+  finalize,
+  map,
+  merge,
+  of,
+  shareReplay,
+  switchMap,
+  tap
+} from "rxjs"
+
+import {
+  getElementContentSize,
+  getElementSize,
+  watchElementContentOffset
+} from "~/browser"
+
+/* ----------------------------------------------------------------------------
+ * Data
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Intersection observer entry subject
+ */
+const entry$ = new Subject<IntersectionObserverEntry>()
+
+/**
+ * Intersection observer observable
+ *
+ * This observable will create an `IntersectionObserver` on first subscription
+ * and will automatically terminate it when there are no more subscribers.
+ *
+ * @see https://bit.ly/3iIYfEm - Google Groups on performance
+ */
+const observer$ = defer(() => of(
+  new IntersectionObserver(entries => {
+    for (const entry of entries)
+      entry$.next(entry)
+  }, {
+    threshold: 0
+  })
+))
+  .pipe(
+    switchMap(observer => merge(NEVER, of(observer))
+      .pipe(
+        finalize(() => observer.disconnect())
+      )
+    ),
+    shareReplay(1)
+  )
+
+/* ----------------------------------------------------------------------------
+ * Functions
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Watch element visibility
+ *
+ * @param el - Element
+ *
+ * @returns Element visibility observable
+ */
+export function watchElementVisibility(
+  el: HTMLElement
+): Observable<boolean> {
+  return observer$
+    .pipe(
+      tap(observer => observer.observe(el)),
+      switchMap(observer => entry$
+        .pipe(
+          filter(({ target }) => target === el),
+          finalize(() => observer.unobserve(el)),
+          map(({ isIntersecting }) => isIntersecting)
+        )
+      )
+    )
+}
+
+/**
+ * Watch element boundary
+ *
+ * This function returns an observable which emits whether the bottom content
+ * boundary (= scroll offset) of an element is within a certain threshold.
+ *
+ * @param el - Element
+ * @param threshold - Threshold
+ *
+ * @returns Element boundary observable
+ */
+export function watchElementBoundary(
+  el: HTMLElement, threshold = 16
+): Observable<boolean> {
+  return watchElementContentOffset(el)
+    .pipe(
+      map(({ y }) => {
+        const visible = getElementSize(el)
+        const content = getElementContentSize(el)
+        return y >= (
+          content.height - visible.height - threshold
+        )
+      }),
+      distinctUntilChanged()
+    )
+}
diff --git a/src/templates/assets/javascripts/browser/index.ts b/src/templates/assets/javascripts/browser/index.ts
new file mode 100644
index 00000000..f1ee2bae
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/index.ts
@@ -0,0 +1,32 @@
+/*
+ * 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.
+ */
+
+export * from "./document"
+export * from "./element"
+export * from "./keyboard"
+export * from "./location"
+export * from "./media"
+export * from "./request"
+export * from "./script"
+export * from "./toggle"
+export * from "./viewport"
+export * from "./worker"
diff --git a/src/templates/assets/javascripts/browser/keyboard/index.ts b/src/templates/assets/javascripts/browser/keyboard/index.ts
new file mode 100644
index 00000000..783f2cda
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/keyboard/index.ts
@@ -0,0 +1,148 @@
+/*
+ * 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 {
+  EMPTY,
+  Observable,
+  filter,
+  fromEvent,
+  map,
+  merge,
+  share,
+  startWith,
+  switchMap
+} from "rxjs"
+
+import { getActiveElement } from "../element"
+import { getToggle } from "../toggle"
+
+/* ----------------------------------------------------------------------------
+ * Types
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Keyboard mode
+ */
+export type KeyboardMode =
+  | "global"                           /* Global */
+  | "search"                           /* Search is open */
+
+/* ------------------------------------------------------------------------- */
+
+/**
+ * Keyboard
+ */
+export interface Keyboard {
+  mode: KeyboardMode                   /* Keyboard mode */
+  type: string                         /* Key type */
+  claim(): void                        /* Key claim */
+}
+
+/* ----------------------------------------------------------------------------
+ * Helper functions
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Check whether an element may receive keyboard input
+ *
+ * @param el - Element
+ * @param type - Key type
+ *
+ * @returns Test result
+ */
+function isSusceptibleToKeyboard(
+  el: HTMLElement, type: string
+): boolean {
+  switch (el.constructor) {
+
+    /* Input elements */
+    case HTMLInputElement:
+      /* @ts-expect-error - omit unnecessary type cast */
+      if (el.type === "radio")
+        return /^Arrow/.test(type)
+      else
+        return true
+
+    /* Select element and textarea */
+    case HTMLSelectElement:
+    case HTMLTextAreaElement:
+      return true
+
+    /* Everything else */
+    default:
+      return el.isContentEditable
+  }
+}
+
+/* ----------------------------------------------------------------------------
+ * Functions
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Watch composition events
+ *
+ * @returns Composition observable
+ */
+export function watchComposition(): Observable<boolean> {
+  return merge(
+    fromEvent(window, "compositionstart").pipe(map(() => true)),
+    fromEvent(window, "compositionend").pipe(map(() => false))
+  )
+    .pipe(
+      startWith(false)
+    )
+}
+
+/**
+ * Watch keyboard
+ *
+ * @returns Keyboard observable
+ */
+export function watchKeyboard(): Observable<Keyboard> {
+  const keyboard$ = fromEvent<KeyboardEvent>(window, "keydown")
+    .pipe(
+      filter(ev => !(ev.metaKey || ev.ctrlKey)),
+      map(ev => ({
+        mode: getToggle("search") ? "search" : "global",
+        type: ev.key,
+        claim() {
+          ev.preventDefault()
+          ev.stopPropagation()
+        }
+      } as Keyboard)),
+      filter(({ mode, type }) => {
+        if (mode === "global") {
+          const active = getActiveElement()
+          if (typeof active !== "undefined")
+            return !isSusceptibleToKeyboard(active, type)
+        }
+        return true
+      }),
+      share()
+    )
+
+  /* Don't emit during composition events - see https://bit.ly/3te3Wl8 */
+  return watchComposition()
+    .pipe(
+      switchMap(active => !active ? keyboard$ : EMPTY)
+    )
+}
diff --git a/src/templates/assets/javascripts/browser/location/_/index.ts b/src/templates/assets/javascripts/browser/location/_/index.ts
new file mode 100644
index 00000000..2672fa74
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/location/_/index.ts
@@ -0,0 +1,85 @@
+/*
+ * 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 { Subject } from "rxjs"
+
+import { feature } from "~/_"
+import { h } from "~/utilities"
+
+/* ----------------------------------------------------------------------------
+ * Functions
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Retrieve location
+ *
+ * This function returns a `URL` object (and not `Location`) to normalize the
+ * typings across the application. Furthermore, locations need to be tracked
+ * without setting them and `Location` is a singleton which represents the
+ * current location.
+ *
+ * @returns URL
+ */
+export function getLocation(): URL {
+  return new URL(location.href)
+}
+
+/**
+ * Set location
+ *
+ * If instant navigation is enabled, this function creates a temporary anchor
+ * element, sets the `href` attribute, appends it to the body, clicks it, and
+ * then removes it again. The event will bubble up the DOM and trigger be
+ * intercepted by the instant loading business logic.
+ *
+ * Note that we must append and remove the anchor element, or the event will
+ * not bubble up the DOM, making it impossible to intercept it.
+ *
+ * @param url - URL to navigate to
+ * @param navigate - Force navigation
+ */
+export function setLocation(
+  url: URL | HTMLLinkElement, navigate = false
+): void {
+  if (feature("navigation.instant") && !navigate) {
+    const el = h("a", { href: url.href })
+    document.body.appendChild(el)
+    el.click()
+    el.remove()
+
+  // If we're not using instant navigation, and the page should not be reloaded
+  // just instruct the browser to navigate to the given URL
+  } else {
+    location.href = url.href
+  }
+}
+
+/* ------------------------------------------------------------------------- */
+
+/**
+ * Watch location
+ *
+ * @returns Location subject
+ */
+export function watchLocation(): Subject<URL> {
+  return new Subject<URL>()
+}
diff --git a/src/templates/assets/javascripts/browser/location/hash/index.ts b/src/templates/assets/javascripts/browser/location/hash/index.ts
new file mode 100644
index 00000000..5d3a134a
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/location/hash/index.ts
@@ -0,0 +1,104 @@
+/*
+ * 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,
+  filter,
+  fromEvent,
+  map,
+  merge,
+  shareReplay,
+  startWith
+} from "rxjs"
+
+import { getOptionalElement } from "~/browser"
+import { h } from "~/utilities"
+
+/* ----------------------------------------------------------------------------
+ * Functions
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Retrieve location hash
+ *
+ * @returns Location hash
+ */
+export function getLocationHash(): string {
+  return location.hash.slice(1)
+}
+
+/**
+ * Set location hash
+ *
+ * Setting a new fragment identifier via `location.hash` will have no effect
+ * if the value doesn't change. When a new fragment identifier is set, we want
+ * the browser to target the respective element at all times, which is why we
+ * use this dirty little trick.
+ *
+ * @param hash - Location hash
+ */
+export function setLocationHash(hash: string): void {
+  const el = h("a", { href: hash })
+  el.addEventListener("click", ev => ev.stopPropagation())
+  el.click()
+}
+
+/* ------------------------------------------------------------------------- */
+
+/**
+ * Watch location hash
+ *
+ * @param location$ - Location observable
+ *
+ * @returns Location hash observable
+ */
+export function watchLocationHash(
+  location$: Observable<URL>
+): Observable<string> {
+  return merge(
+    fromEvent<HashChangeEvent>(window, "hashchange"),
+    location$
+  )
+    .pipe(
+      map(getLocationHash),
+      startWith(getLocationHash()),
+      filter(hash => hash.length > 0),
+      shareReplay(1)
+    )
+}
+
+/**
+ * Watch location target
+ *
+ * @param location$ - Location observable
+ *
+ * @returns Location target observable
+ */
+export function watchLocationTarget(
+  location$: Observable<URL>
+): Observable<HTMLElement> {
+  return watchLocationHash(location$)
+    .pipe(
+      map(id => getOptionalElement(`[id="${id}"]`)!),
+      filter(el => typeof el !== "undefined")
+    )
+}
diff --git a/src/templates/assets/javascripts/browser/location/index.ts b/src/templates/assets/javascripts/browser/location/index.ts
new file mode 100644
index 00000000..d77a5444
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/location/index.ts
@@ -0,0 +1,24 @@
+/*
+ * 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.
+ */
+
+export * from "./_"
+export * from "./hash"
diff --git a/src/templates/assets/javascripts/browser/media/index.ts b/src/templates/assets/javascripts/browser/media/index.ts
new file mode 100644
index 00000000..dd7400d4
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/media/index.ts
@@ -0,0 +1,95 @@
+/*
+ * 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 {
+  EMPTY,
+  Observable,
+  fromEvent,
+  fromEventPattern,
+  map,
+  merge,
+  startWith,
+  switchMap
+} from "rxjs"
+
+/* ----------------------------------------------------------------------------
+ * Functions
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Watch media query
+ *
+ * Note that although `MediaQueryList.addListener` is deprecated we have to
+ * use it, because it's the only way to ensure proper downward compatibility.
+ *
+ * @see https://bit.ly/3dUBH2m - GitHub issue
+ *
+ * @param query - Media query
+ *
+ * @returns Media observable
+ */
+export function watchMedia(query: string): Observable<boolean> {
+  const media = matchMedia(query)
+  return fromEventPattern<boolean>(next => (
+    media.addListener(() => next(media.matches))
+  ))
+    .pipe(
+      startWith(media.matches)
+    )
+}
+
+/**
+ * Watch print mode
+ *
+ * @returns Print observable
+ */
+export function watchPrint(): Observable<boolean> {
+  const media = matchMedia("print")
+  return merge(
+    fromEvent(window, "beforeprint").pipe(map(() => true)),
+    fromEvent(window, "afterprint").pipe(map(() => false))
+  )
+    .pipe(
+      startWith(media.matches)
+    )
+}
+
+/* ------------------------------------------------------------------------- */
+
+/**
+ * Toggle an observable with a media observable
+ *
+ * @template T - Data type
+ *
+ * @param query$ - Media observable
+ * @param factory - Observable factory
+ *
+ * @returns Toggled observable
+ */
+export function at<T>(
+  query$: Observable<boolean>, factory: () => Observable<T>
+): Observable<T> {
+  return query$
+    .pipe(
+      switchMap(active => active ? factory() : EMPTY)
+    )
+}
diff --git a/src/templates/assets/javascripts/browser/request/index.ts b/src/templates/assets/javascripts/browser/request/index.ts
new file mode 100644
index 00000000..74a56a64
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/request/index.ts
@@ -0,0 +1,141 @@
+/*
+ * 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,
+  Subject,
+  map,
+  shareReplay,
+  switchMap
+} from "rxjs"
+
+/* ----------------------------------------------------------------------------
+ * Helper types
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Options
+ */
+interface Options {
+  progress$?: Subject<number>          // Progress subject
+}
+
+/* ----------------------------------------------------------------------------
+ * Functions
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Fetch the given URL
+ *
+ * If the request fails (e.g. when dispatched from `file://` locations), the
+ * observable will complete without emitting a value.
+ *
+ * @param url - Request URL
+ * @param options - Options
+ *
+ * @returns Response observable
+ */
+export function request(
+  url: URL | string, options?: Options
+): Observable<Blob> {
+  return new Observable<Blob>(observer => {
+    const req = new XMLHttpRequest()
+    req.open("GET",  `${url}`)
+    req.responseType = "blob"
+
+    // Handle response
+    req.addEventListener("load", () => {
+      if (req.status >= 200 && req.status < 300) {
+        observer.next(req.response)
+        observer.complete()
+      } else {
+        observer.error(new Error(req.statusText))
+      }
+    })
+
+    // Handle network errors
+    req.addEventListener("error", () => {
+      observer.error(new Error("Network Error"))
+    })
+
+    // Handle aborted requests
+    req.addEventListener("abort", () => {
+      observer.error(new Error("Request aborted"))
+    })
+
+    // Handle download progress
+    if (typeof options?.progress$ !== "undefined") {
+      req.addEventListener("progress", event => {
+        options.progress$!.next((event.loaded / event.total) * 100)
+      })
+
+      // Immediately set progress to 5% to indicate that we're loading
+      options.progress$.next(5)
+    }
+
+    // Send request
+    req.send()
+  })
+}
+
+/* ------------------------------------------------------------------------- */
+
+/**
+ * Fetch JSON from the given URL
+ *
+ * @template T - Data type
+ *
+ * @param url - Request URL
+ * @param options - Options
+ *
+ * @returns Data observable
+ */
+export function requestJSON<T>(
+  url: URL | string, options?: Options
+): Observable<T> {
+  return request(url, options)
+    .pipe(
+      switchMap(res => res.text()),
+      map(body => JSON.parse(body) as T),
+      shareReplay(1)
+    )
+}
+
+/**
+ * Fetch XML from the given URL
+ *
+ * @param url - Request URL
+ * @param options - Options
+ *
+ * @returns Data observable
+ */
+export function requestXML(
+  url: URL | string, options?: Options
+): Observable<Document> {
+  const dom = new DOMParser()
+  return request(url, options)
+    .pipe(
+      switchMap(res => res.text()),
+      map(res => dom.parseFromString(res, "text/xml")),
+      shareReplay(1)
+    )
+}
diff --git a/src/templates/assets/javascripts/browser/script/index.ts b/src/templates/assets/javascripts/browser/script/index.ts
new file mode 100644
index 00000000..ef5c89e6
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/script/index.ts
@@ -0,0 +1,70 @@
+/*
+ * 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,
+  defer,
+  finalize,
+  fromEvent,
+  map,
+  merge,
+  switchMap,
+  take,
+  throwError
+} from "rxjs"
+
+import { h } from "~/utilities"
+
+/* ----------------------------------------------------------------------------
+ * Functions
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Create and load a `script` element
+ *
+ * This function returns an observable that will emit when the script was
+ * successfully loaded, or throw an error if it wasn't.
+ *
+ * @param src - Script URL
+ *
+ * @returns Script observable
+ */
+export function watchScript(src: string): Observable<void> {
+  const script = h("script", { src })
+  return defer(() => {
+    document.head.appendChild(script)
+    return merge(
+      fromEvent(script, "load"),
+      fromEvent(script, "error")
+        .pipe(
+          switchMap(() => (
+            throwError(() => new ReferenceError(`Invalid script: ${src}`))
+          ))
+        )
+    )
+      .pipe(
+        map(() => undefined),
+        finalize(() => document.head.removeChild(script)),
+        take(1)
+      )
+  })
+}
diff --git a/src/templates/assets/javascripts/browser/toggle/index.ts b/src/templates/assets/javascripts/browser/toggle/index.ts
new file mode 100644
index 00000000..0be4b29d
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/toggle/index.ts
@@ -0,0 +1,102 @@
+/*
+ * 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,
+  fromEvent,
+  map,
+  startWith
+} from "rxjs"
+
+import { getElement } from "../element"
+
+/* ----------------------------------------------------------------------------
+ * Types
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Toggle
+ */
+export type Toggle =
+  | "drawer"                           /* Toggle for drawer */
+  | "search"                           /* Toggle for search */
+
+/* ----------------------------------------------------------------------------
+ * Data
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Toggle map
+ */
+const toggles: Record<Toggle, HTMLInputElement> = {
+  drawer: getElement("[data-md-toggle=drawer]"),
+  search: getElement("[data-md-toggle=search]")
+}
+
+/* ----------------------------------------------------------------------------
+ * Functions
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Retrieve the value of a toggle
+ *
+ * @param name - Toggle
+ *
+ * @returns Toggle value
+ */
+export function getToggle(name: Toggle): boolean {
+  return toggles[name].checked
+}
+
+/**
+ * Set toggle
+ *
+ * Simulating a click event seems to be the most cross-browser compatible way
+ * of changing the value while also emitting a `change` event. Before, Material
+ * used `CustomEvent` to programmatically change the value of a toggle, but this
+ * is a much simpler and cleaner solution which doesn't require a polyfill.
+ *
+ * @param name - Toggle
+ * @param value - Toggle value
+ */
+export function setToggle(name: Toggle, value: boolean): void {
+  if (toggles[name].checked !== value)
+    toggles[name].click()
+}
+
+/* ------------------------------------------------------------------------- */
+
+/**
+ * Watch toggle
+ *
+ * @param name - Toggle
+ *
+ * @returns Toggle value observable
+ */
+export function watchToggle(name: Toggle): Observable<boolean> {
+  const el = toggles[name]
+  return fromEvent(el, "change")
+    .pipe(
+      map(() => el.checked),
+      startWith(el.checked)
+    )
+}
diff --git a/src/templates/assets/javascripts/browser/viewport/_/index.ts b/src/templates/assets/javascripts/browser/viewport/_/index.ts
new file mode 100644
index 00000000..09c45f32
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/viewport/_/index.ts
@@ -0,0 +1,69 @@
+/*
+ * 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,
+  map,
+  shareReplay
+} from "rxjs"
+
+import {
+  ViewportOffset,
+  watchViewportOffset
+} from "../offset"
+import {
+  ViewportSize,
+  watchViewportSize
+} from "../size"
+
+/* ----------------------------------------------------------------------------
+ * Types
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Viewport
+ */
+export interface Viewport {
+  offset: ViewportOffset               /* Viewport offset */
+  size: ViewportSize                   /* Viewport size */
+}
+
+/* ----------------------------------------------------------------------------
+ * Functions
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Watch viewport
+ *
+ * @returns Viewport observable
+ */
+export function watchViewport(): Observable<Viewport> {
+  return combineLatest([
+    watchViewportOffset(),
+    watchViewportSize()
+  ])
+    .pipe(
+      map(([offset, size]) => ({ offset, size })),
+      shareReplay(1)
+    )
+}
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
+      }))
+    )
+}
diff --git a/src/templates/assets/javascripts/browser/viewport/index.ts b/src/templates/assets/javascripts/browser/viewport/index.ts
new file mode 100644
index 00000000..b3d135e9
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/viewport/index.ts
@@ -0,0 +1,26 @@
+/*
+ * 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.
+ */
+
+export * from "./_"
+export * from "./at"
+export * from "./offset"
+export * from "./size"
diff --git a/src/templates/assets/javascripts/browser/viewport/offset/index.ts b/src/templates/assets/javascripts/browser/viewport/offset/index.ts
new file mode 100644
index 00000000..63d37dd2
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/viewport/offset/index.ts
@@ -0,0 +1,78 @@
+/*
+ * 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,
+  fromEvent,
+  map,
+  merge,
+  startWith
+} from "rxjs"
+
+/* ----------------------------------------------------------------------------
+ * Types
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Viewport offset
+ */
+export interface ViewportOffset {
+  x: number                            /* Horizontal offset */
+  y: number                            /* Vertical offset */
+}
+
+/* ----------------------------------------------------------------------------
+ * Functions
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Retrieve viewport offset
+ *
+ * On iOS Safari, viewport offset can be negative due to overflow scrolling.
+ * As this may induce strange behaviors downstream, we'll just limit it to 0.
+ *
+ * @returns Viewport offset
+ */
+export function getViewportOffset(): ViewportOffset {
+  return {
+    x: Math.max(0, scrollX),
+    y: Math.max(0, scrollY)
+  }
+}
+
+/* ------------------------------------------------------------------------- */
+
+/**
+ * Watch viewport offset
+ *
+ * @returns Viewport offset observable
+ */
+export function watchViewportOffset(): Observable<ViewportOffset> {
+  return merge(
+    fromEvent(window, "scroll", { passive: true }),
+    fromEvent(window, "resize", { passive: true })
+  )
+    .pipe(
+      map(getViewportOffset),
+      startWith(getViewportOffset())
+    )
+}
diff --git a/src/templates/assets/javascripts/browser/viewport/size/index.ts b/src/templates/assets/javascripts/browser/viewport/size/index.ts
new file mode 100644
index 00000000..06694888
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/viewport/size/index.ts
@@ -0,0 +1,71 @@
+/*
+ * 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,
+  fromEvent,
+  map,
+  startWith
+} from "rxjs"
+
+/* ----------------------------------------------------------------------------
+ * Types
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Viewport size
+ */
+export interface ViewportSize {
+  width: number                        /* Viewport width */
+  height: number                       /* Viewport height */
+}
+
+/* ----------------------------------------------------------------------------
+ * Functions
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Retrieve viewport size
+ *
+ * @returns Viewport size
+ */
+export function getViewportSize(): ViewportSize {
+  return {
+    width:  innerWidth,
+    height: innerHeight
+  }
+}
+
+/* ------------------------------------------------------------------------- */
+
+/**
+ * Watch viewport size
+ *
+ * @returns Viewport size observable
+ */
+export function watchViewportSize(): Observable<ViewportSize> {
+  return fromEvent(window, "resize", { passive: true })
+    .pipe(
+      map(getViewportSize),
+      startWith(getViewportSize())
+    )
+}
diff --git a/src/templates/assets/javascripts/browser/worker/index.ts b/src/templates/assets/javascripts/browser/worker/index.ts
new file mode 100644
index 00000000..12e4e63b
--- /dev/null
+++ b/src/templates/assets/javascripts/browser/worker/index.ts
@@ -0,0 +1,112 @@
+/*
+ * 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,
+  Subject,
+  endWith,
+  fromEvent,
+  ignoreElements,
+  mergeWith,
+  share,
+  takeUntil
+} from "rxjs"
+
+/* ----------------------------------------------------------------------------
+ * Types
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Worker message
+ */
+export interface WorkerMessage {
+  type: unknown                        /* Message type */
+  data?: unknown                       /* Message data */
+}
+
+/* ----------------------------------------------------------------------------
+ * Helper functions
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Create an observable for receiving from a web worker
+ *
+ * @template T - Data type
+ *
+ * @param worker - Web worker
+ *
+ * @returns Message observable
+ */
+function recv<T>(worker: Worker): Observable<T> {
+  return fromEvent<MessageEvent<T>, T>(worker, "message", ev => ev.data)
+}
+
+/**
+ * Create a subject for sending to a web worker
+ *
+ * @template T - Data type
+ *
+ * @param worker - Web worker
+ *
+ * @returns Message subject
+ */
+function send<T>(worker: Worker): Subject<T> {
+  const send$ = new Subject<T>()
+  send$.subscribe(data => worker.postMessage(data))
+
+  /* Return message subject */
+  return send$
+}
+
+/* ----------------------------------------------------------------------------
+ * Functions
+ * ------------------------------------------------------------------------- */
+
+/**
+ * Create a bidirectional communication channel to a web worker
+ *
+ * @template T - Data type
+ *
+ * @param url - Worker URL
+ * @param worker - Worker
+ *
+ * @returns Worker subject
+ */
+export function watchWorker<T extends WorkerMessage>(
+  url: string, worker = new Worker(url)
+): Subject<T> {
+  const recv$ = recv<T>(worker)
+  const send$ = send<T>(worker)
+
+  /* Create worker subject and forward messages */
+  const worker$ = new Subject<T>()
+  worker$.subscribe(send$)
+
+  /* Return worker subject */
+  const done$ = send$.pipe(ignoreElements(), endWith(true))
+  return worker$
+    .pipe(
+      ignoreElements(),
+      mergeWith(recv$.pipe(takeUntil(done$))),
+      share()
+    ) as Subject<T>
+}