a95826f60c
* DEV: `Discourse.baseUri` does not exist This never could have worked - should have been `Discourse.BaseUri` if anything. * DEV: Remove Discourse.Environment * DEV: Remove `Discourse.disableMissingIconWarning` * DEV: A bunch more missing environment checks
90 lines
2.4 KiB
JavaScript
90 lines
2.4 KiB
JavaScript
import { isTesting } from "discourse-common/config/environment";
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import AppEvents from "discourse/services/app-events";
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let _skipUpdate;
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let _rootElement;
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export function configureEyeline(opts) {
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if (opts) {
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_skipUpdate = opts.skipUpdate;
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_rootElement = opts.rootElement;
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} else {
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_skipUpdate = isTesting();
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_rootElement = null;
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}
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}
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configureEyeline();
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// Track visible elements on the screen.
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const Eyeline = function Eyeline(selector) {
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this.selector = selector;
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this.appEvents = AppEvents.create();
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};
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Eyeline.prototype.on = function(name, cb) {
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this.appEvents.on(name, cb);
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};
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Eyeline.prototype.off = function(name, cb) {
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this.appEvents.off(name, cb);
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};
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Eyeline.prototype.update = function() {
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if (_skipUpdate) {
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return;
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}
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const docViewTop = _rootElement
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? $(_rootElement).scrollTop()
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: $(window).scrollTop();
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const windowHeight = _rootElement
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? $(_rootElement).height()
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: $(window).height();
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const docViewBottom = docViewTop + windowHeight;
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const $elements = $(this.selector);
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const bottomOffset = _rootElement
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? $elements.last().position()
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: $elements.last().offset();
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let atBottom = false;
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if (bottomOffset) {
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atBottom =
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bottomOffset.top <= docViewBottom && bottomOffset.top >= docViewTop;
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}
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let { appEvents } = this;
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return $elements.each((i, elem) => {
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const $elem = $(elem),
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elemTop = _rootElement ? $elem.position().top : $elem.offset().top,
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elemBottom = elemTop + $elem.height();
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let markSeen = false;
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// Make sure the element is visible
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if (!$elem.is(":visible")) return true;
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// It's seen if...
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// ...the element is vertically within the top and botom
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if (elemTop <= docViewBottom && elemTop >= docViewTop) markSeen = true;
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// ...the element top is above the top and the bottom is below the bottom (large elements)
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if (elemTop <= docViewTop && elemBottom >= docViewBottom) markSeen = true;
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// ...we're at the bottom and the bottom of the element is visible (large bottom elements)
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if (atBottom && elemBottom >= docViewTop) markSeen = true;
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if (!markSeen) return true;
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// If you hit the bottom we mark all the elements as seen. Otherwise, just the first one
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if (!atBottom) {
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return false;
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}
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if (i === $elements.length - 1) {
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return appEvents.trigger("sawBottom", { detail: $elem });
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}
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});
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};
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export default Eyeline;
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