102 lines
3.1 KiB
JavaScript
102 lines
3.1 KiB
JavaScript
/*
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* Copyright (c) 2016-2017 Martin Donath <martin.donath@squidfunk.com>
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to
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* deal in the Software without restriction, including without limitation the
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* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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* sell copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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/* ----------------------------------------------------------------------------
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* Class
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* ------------------------------------------------------------------------- */
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export default class Shadow {
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/**
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* Show or hide header shadow depending on page y-offset
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*
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* @constructor
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*
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* @property {HTMLElement} el_ - Content container
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* @property {HTMLElement} header_ - Header
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* @property {number} height_ - Offset height of previous nodes
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* @property {boolean} active_ - Header shadow state
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*
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* @param {(string|HTMLElement)} el - Selector or HTML element
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* @param {(string|HTMLElement)} header - Selector or HTML element
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*/
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constructor(el, header) {
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let ref = (typeof el === "string")
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? document.querySelector(el)
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: el
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if (!(ref instanceof HTMLElement) ||
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!(ref.parentNode instanceof HTMLElement))
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throw new ReferenceError
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this.el_ = ref.parentNode
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/* Retrieve header */
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ref = (typeof header === "string")
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? document.querySelector(header)
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: header
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if (!(ref instanceof HTMLElement))
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throw new ReferenceError
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this.header_ = ref
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/* Initialize height and state */
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this.height_ = 0
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this.active_ = false
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}
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/**
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* Calculate total height of previous nodes
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*/
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setup() {
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let current = this.el_
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while ((current = current.previousElementSibling)) {
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if (!(current instanceof HTMLElement))
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throw new ReferenceError
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this.height_ += current.offsetHeight
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}
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this.update()
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}
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/**
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* Update shadow state
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*
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* @param {Event} ev - Event
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*/
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update(ev) {
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if (ev && (ev.type === "resize" || ev.type === "orientationchange")) {
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this.height_ = 0
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this.setup()
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} else {
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const active = window.pageYOffset >= this.height_
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if (active !== this.active_)
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this.header_.dataset.mdState = (this.active_ = active) ? "shadow" : ""
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}
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}
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/**
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* Reset shadow state
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*/
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reset() {
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this.header_.dataset.mdState = ""
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this.height_ = 0
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this.active_ = false
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}
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}
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