Files
mkdocs-material/src/assets/javascripts/theme/component/sidebar/index.ts
2019-11-27 19:12:49 +01:00

151 lines
4.3 KiB
TypeScript

/*
* Copyright (c) 2016-2019 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 { equals } from "ramda"
import {
MonoTypeOperatorFunction,
Observable,
animationFrameScheduler,
combineLatest,
pipe
} from "rxjs"
import {
distinctUntilChanged,
finalize,
map,
observeOn,
shareReplay,
tap
} from "rxjs/operators"
import { ViewportOffset } from "../../../ui"
import {
resetSidebarHeight,
resetSidebarLock,
setSidebarHeight,
setSidebarLock
} from "../../action"
import { Main } from "../main"
/* ----------------------------------------------------------------------------
* Types
* ------------------------------------------------------------------------- */
/**
* Sidebar
*/
export interface Sidebar {
height: number /* Sidebar height */
lock: boolean /* Sidebar lock */
}
/* ----------------------------------------------------------------------------
* Function types
* ------------------------------------------------------------------------- */
/**
* Options
*/
interface Options {
offset$: Observable<ViewportOffset> /* Viewport offset observable */
main$: Observable<Main> /* Main area observable */
}
/* ----------------------------------------------------------------------------
* Functions
* ------------------------------------------------------------------------- */
/**
* Watch sidebar
*
* This function returns an observable that computes the visual parameters of
* the given element (a sidebar) from the vertical viewport offset, as well as
* the height of the main area. When the page is scrolled beyond the header,
* the sidebar is locked and fills the remaining space.
*
* @param el - Sidebar element
* @param options - Options
*
* @return Sidebar observable
*/
export function watchSidebar(
el: HTMLElement, { offset$, main$ }: Options
): Observable<Sidebar> {
/* Adjust for internal main area offset */
const adjust = parseFloat(
getComputedStyle(el.parentElement!)
.getPropertyValue("padding-top")
)
/* Compute the sidebar's available height */
const height$ = combineLatest([offset$, main$])
.pipe(
map(([{ y }, { offset, height }]) => {
return height - adjust + Math.min(adjust, Math.max(0, y - offset))
})
)
/* Compute whether the sidebar should be locked */
const lock$ = combineLatest([offset$, main$])
.pipe(
map(([{ y }, { offset }]) => y >= offset + adjust)
)
/* Combine into single hot observable */
return combineLatest([height$, lock$])
.pipe(
map(([height, lock]) => ({ height, lock })),
distinctUntilChanged<Sidebar>(equals),
shareReplay(1)
)
}
/* ------------------------------------------------------------------------- */
/**
* Paint sidebar from source observable
*
* @param el - Sidebar element
*
* @return Operator function
*/
export function paintSidebar(
el: HTMLElement
): MonoTypeOperatorFunction<Sidebar> {
return pipe(
/* Defer repaint to next animation frame */
observeOn(animationFrameScheduler),
tap(({ height, lock }) => {
setSidebarHeight(el, height)
setSidebarLock(el, lock)
}),
/* Reset on complete or error */
finalize(() => {
resetSidebarHeight(el)
resetSidebarLock(el)
})
)
}