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import { getUser, onAuthChange } from './auth.js';
// Reserved space for advertising.
//
// This renders an empty, correctly sized box. It loads nothing, calls
// nothing, and tracks nobody. Its only job is to hold the space so that
// wiring a real network later does not move the rest of the page around
// after it loads, which is the usual way ads ruin a layout.
//
// Before any network goes in, three things have to change together:
//
// 1. The Content-Security-Policy in web/serve.mjs forbids third-party
// script, frame and image sources. An ad network needs all three, and
// relaxing them is the single largest change to this app's security
// posture. script-src in particular currently has no third-party source
// at all.
// 2. The privacy page in app.js says there is no advertising and no
// third-party script. That becomes untrue the moment a tag is added.
// 3. An ad network sets cookies and profiles visitors, which brings
// consent requirements with it. There is no consent mechanism here.
//
// Shown to signed-out visitors and to signed-in accounts without the
// supporter flag. Never shown on the typing screen: interrupting somebody
// mid-test is the one placement that would cost more than it earns.
const SIZES = {
// Roughly a leaderboard unit, and a mobile banner below the breakpoint.
banner: { w: 728, h: 90, mobileW: 320, mobileH: 100 },
};
export function shouldShowAds() {
const user = getUser();
// A signed-out visitor is a free user for this purpose.
return !user || !user.is_supporter;
}
/// Renders the slot into `root`. Returns a cleanup function.
export function renderAdSlot(root, { size = 'banner', label = 'Advertisement' } = {}) {
const spec = SIZES[size] || SIZES.banner;
const wrap = document.createElement('div');
wrap.className = `ad-slot ad-slot-${size}`;
wrap.style.setProperty('--ad-w', `${spec.w}px`);
wrap.style.setProperty('--ad-h', `${spec.h}px`);
wrap.style.setProperty('--ad-mobile-w', `${spec.mobileW}px`);
wrap.style.setProperty('--ad-mobile-h', `${spec.mobileH}px`);
// Labelled for what it is. An unlabelled empty box reads as a bug.
wrap.innerHTML = `<span class="ad-slot-label">${label}</span>`;
function paint() {
wrap.hidden = !shouldShowAds();
}
paint();
const unsubscribe = onAuthChange(paint);
root.appendChild(wrap);
return () => {
unsubscribe();
wrap.remove();
};
}
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