Files
mkdocs-material/src/assets/javascripts/patches/scrollfix/index.ts
2020-08-22 18:36:37 +02:00

105 lines
3.4 KiB
TypeScript

/*
* 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 { NEVER, Observable, fromEvent, iif, merge } from "rxjs"
import { map, mapTo, shareReplay, switchMap } from "rxjs/operators"
import { getElements } from "browser"
/* ----------------------------------------------------------------------------
* Helper types
* ------------------------------------------------------------------------- */
/**
* Patch options
*/
interface PatchOptions {
document$: Observable<Document> /* Document observable */
}
/* ----------------------------------------------------------------------------
* Helper functions
* ------------------------------------------------------------------------- */
/**
* Check whether the given device is an Apple device
*
* @return Test result
*/
function isAppleDevice(): boolean {
return /(iPad|iPhone|iPod)/.test(navigator.userAgent)
}
/* ----------------------------------------------------------------------------
* Functions
* ------------------------------------------------------------------------- */
/**
* Patch all elements with `data-md-scrollfix` attributes
*
* This is a year-old patch which ensures that overflow scrolling works at the
* top and bottom of containers on iOS by ensuring a `1px` scroll offset upon
* the start of a touch event.
*
* @see https://bit.ly/2SCtAOO - Original source
*
* @param options - Options
*/
export function patchScrollfix(
{ document$ }: PatchOptions
): void {
const els$ = document$
.pipe(
map(() => getElements("[data-md-scrollfix]")),
shareReplay({ bufferSize: 1, refCount: true })
)
/* Remove marker attribute, so we'll only add the fix once */
els$.subscribe(els => {
for (const el of els)
el.removeAttribute("data-md-scrollfix")
})
/* Patch overflow scrolling on touch start */
iif(isAppleDevice, els$, NEVER)
.pipe(
switchMap(els => merge(...els.map(el => (
fromEvent(el, "touchstart", { passive: true })
.pipe(
mapTo(el)
)
))))
)
.subscribe(el => {
const top = el.scrollTop
/* We're at the top of the container */
if (top === 0) {
el.scrollTop = 1
/* We're at the bottom of the container */
} else if (top + el.offsetHeight === el.scrollHeight) {
el.scrollTop = top - 1
}
})
}