NetNewsWire/Shared/Article Rendering/newsfoot.js

172 lines
5.2 KiB
JavaScript

// @ts-check
(function () {
/** @param {Node | null} el */
const remove = (el) => { if (el) el.parentElement.removeChild(el) };
const stripPx = (s) => +s.slice(0, -2);
/** @param {string} tag
* @param {string} cls
* @returns HTMLElement
*/
function newEl(tag, cls) {
const el = document.createElement(tag);
el.classList.add(cls);
return el;
}
/** @type {<T extends any[]>(fn: (...args: T) => void, t: number) => ((...args: T) => void)} */
function debounce(f, ms) {
let t = Date.now();
return (...args) => {
const now = Date.now();
if (now - t < ms) return;
t = now;
f(...args);
};
}
const clsPrefix = "newsfoot-footnote-";
const CONTAINER_CLS = `${clsPrefix}container`;
const POPOVER_CLS = `${clsPrefix}popover`;
const POPOVER_INNER_CLS = `${clsPrefix}popover-inner`;
const POPOVER_ARROW_CLS = `${clsPrefix}popover-arrow`;
/**
* @param {string} content
* @returns {HTMLElement}
*/
function footnoteMarkup(content) {
const popover = newEl("div", POPOVER_CLS);
const arrow = newEl("div", POPOVER_ARROW_CLS);
const inner = newEl("div", POPOVER_INNER_CLS);
popover.appendChild(inner);
popover.appendChild(arrow);
inner.innerHTML = content;
return popover;
}
class Footnote {
/**
* @param {string} content
* @param {Element} fnref
*/
constructor(content, fnref) {
this.popover = footnoteMarkup(content);
this.style = window.getComputedStyle(this.popover);
this.fnref = fnref;
let container = this.fnref.closest(`.${CONTAINER_CLS}`);
container.insertBefore(this.popover, fnref);
container.style.zIndex = 1;
/** @type {HTMLElement} */
this.arrow = this.popover.querySelector(`.${POPOVER_ARROW_CLS}`);
this.reposition();
/** @type {(ev:MouseEvent) => void} */
this.clickoutHandler = (ev) => {
if (!(ev.target instanceof Element)) return;
if (ev.target.closest(`.${POPOVER_CLS}`) === this.popover) return;
if (ev.target === this.fnref) {
ev.stopPropagation();
ev.preventDefault();
}
this.cleanup();
}
document.addEventListener("click", this.clickoutHandler, {capture: true});
this.resizeHandler = debounce(() => this.reposition(), 20);
window.addEventListener("resize", this.resizeHandler);
}
cleanup() {
this.fnref.closest(`.${CONTAINER_CLS}`).style.zIndex = 0;
remove(this.popover);
document.removeEventListener("click", this.clickoutHandler, {capture: true});
window.removeEventListener("resize", this.resizeHandler);
delete this.popover;
delete this.clickoutHandler;
delete this.resizeHandler;
}
reposition() {
const refRect = this.fnref.getBoundingClientRect();
const center = refRect.left + (refRect.width / 2);
const popoverHalfWidth = this.popover.clientWidth / 2;
const marginLeft = stripPx(this.style.marginLeft);
const marginRight = stripPx(this.style.marginRight);
const rightOverhang = center + popoverHalfWidth + marginRight > window.innerWidth;
const leftOverhang = center - (popoverHalfWidth + marginLeft) < 0;
let offset = 0;
if (!leftOverhang && rightOverhang) {
offset = -((center + popoverHalfWidth + marginRight) - window.innerWidth);
}
else if (leftOverhang && !rightOverhang) {
offset = (popoverHalfWidth + marginLeft) - center;
}
this.popover.style.transform = `translate(${offset}px)`;
this.arrow.style.transform = `translate(${-offset}px) rotate(45deg)`;
}
}
/** @param {HTMLAnchorElement} a */
function installContainer(a) {
if (!a.parentElement.matches(`.${CONTAINER_CLS}`)) {
const container = newEl("div", CONTAINER_CLS);
a.parentElement.insertBefore(container, a);
container.appendChild(a);
}
}
function idFromHash(target) {
if (!target.hash) return;
return decodeURIComponent(target.hash.substring(1));
}
/** @type {{fnref(target:HTMLAnchorElement): string|undefined}[]} */
const footnoteFormats = [
{ // Multimarkdown
fnref(target) {
if (!target.matches(".footnote")) return;
return idFromHash(target);
}
}
];
// Handle clicks on the footnote reference
document.addEventListener("click", (ev) => {
if (!(ev.target && ev.target instanceof HTMLAnchorElement)) return;
let targetId = undefined;
for(const f of footnoteFormats) {
targetId = f.fnref(ev.target);
if (targetId) break;
}
if (targetId === undefined) return;
// Only override the default behaviour when we know we can find the
// target element
const targetElement = document.getElementById(targetId);
if (targetElement === null) return;
ev.preventDefault();
installContainer(ev.target);
void new Footnote(targetElement.innerHTML, ev.target);
});
// Handle clicks on the footnote reverse link
document.addEventListener("click", (ev) =>
{
if (!(ev.target && ev.target instanceof HTMLAnchorElement)) return;
if (!ev.target.matches(".footnotes .reversefootnote, .footnotes .footnoteBackLink, .footnotes .footnote-return, .footnotes a[href*='#fn'], .footnotes a[href^='#']")) return;
const id = idFromHash(ev.target);
if (!id) return;
const fnref = document.getElementById(id);
window.scrollTo({ top: fnref.getBoundingClientRect().top + window.scrollY });
ev.preventDefault();
});
}());