Feat: Web loader

Loader/scripts/config.js

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+// Path: Loader/scripts/config.js
+
+export const LOADER_INTENT_STORAGE_KEY = "moku.loader.intent";
+export const LOADER_META_STORAGE_KEY = "moku.loader.meta";
+export const LOADER_SEEN_COOKIE_NAME = "moku_loader_seen";
+export const LOADER_DEFAULT_INTENT = "/";
+export const LOADER_ROOT_PREFIX = "/__loader";
+export const LOADER_HANDOFF_DELAY_MS = 720;
+export const LOADER_SEEN_COOKIE_MAX_AGE_SECONDS = 1800;

Loader/scripts/dom.js

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+// Path: Loader/scripts/dom.js
+
+export const getStatusElement = () => {
+	return document.getElementById("loader-status");
+};
+
+export const getIntentElement = () => {
+	return document.getElementById("loader-intent");
+};
+
+export const setStatus = (value) => {
+	const statusElement = getStatusElement();
+
+	if (statusElement instanceof HTMLElement) {
+		statusElement.textContent = value;
+	}
+};
+
+export const setIntentPreview = (value) => {
+	const intentElement = getIntentElement();
+
+	if (intentElement instanceof HTMLElement) {
+		intentElement.textContent = value;
+	}
+};

Loader/scripts/handoff.js

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+// Path: Loader/scripts/handoff.js
+
+import { LOADER_HANDOFF_DELAY_MS } from "./config.js";
+
+export const scheduleHandoff = (target, onBeforeHandoff) => {
+	window.setTimeout(() => {
+		if (typeof onBeforeHandoff === "function") {
+			onBeforeHandoff();
+		}
+
+		window.location.assign(target);
+	}, LOADER_HANDOFF_DELAY_MS);
+};

Loader/scripts/hints.js

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+// Path: Loader/scripts/hints.js
+
+export const collectClientHints = () => {
+	const navigatorConnection = navigator.connection || navigator.mozConnection || navigator.webkitConnection;
+
+	return {
+		capturedAt: new Date().toISOString(),
+		language: navigator.language,
+		languages: Array.isArray(navigator.languages) ? navigator.languages : [],
+		hardwareConcurrency: navigator.hardwareConcurrency ?? null,
+		deviceMemory: navigator.deviceMemory ?? null,
+		networkType: navigatorConnection?.effectiveType ?? null,
+		saveData: navigatorConnection?.saveData ?? null,
+		viewport: {
+			width: window.innerWidth,
+			height: window.innerHeight,
+		},
+	};
+};

Loader/scripts/intent.js

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+// Path: Loader/scripts/intent.js
+
+import { LOADER_DEFAULT_INTENT, LOADER_ROOT_PREFIX } from "./config.js";
+
+export const getExplicitIntent = () => {
+	const params = new URLSearchParams(window.location.search);
+	const next = params.get("next");
+
+	if (typeof next === "string" && next.startsWith("/")) {
+		return next;
+	}
+
+	return null;
+};
+
+export const getCurrentPathIntent = () => {
+	const current = `${window.location.pathname}${window.location.search}${window.location.hash}`;
+
+	if (current === "/" || current === LOADER_ROOT_PREFIX || current === `${LOADER_ROOT_PREFIX}/` || current.startsWith(`${LOADER_ROOT_PREFIX}/`)) {
+		return LOADER_DEFAULT_INTENT;
+	}
+
+	return current;
+};
+
+export const resolveIntent = () => {
+	return getExplicitIntent() ?? getCurrentPathIntent();
+};
+
+export const resolveHandoffTarget = (intent) => {
+	return intent || LOADER_DEFAULT_INTENT;
+};

Loader/scripts/main.js

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+// Path: Loader/scripts/main.js
+
+import { setIntentPreview, setStatus } from "./dom.js";
+import { scheduleHandoff } from "./handoff.js";
+import { resolveHandoffTarget, resolveIntent } from "./intent.js";
+import { markLoaderSeen, persistLoaderState } from "./storage.js";
+
+const bootLoader = () => {
+	const intent = resolveIntent();
+	const handoffTarget = resolveHandoffTarget(intent);
+
+	setStatus("Capturing route intent");
+	setIntentPreview(intent);
+	persistLoaderState(intent);
+
+	window.setTimeout(() => {
+		setStatus("Preparing handoff");
+	}, 180);
+
+	scheduleHandoff(handoffTarget, () => {
+		setStatus("Handing off to application");
+		markLoaderSeen();
+	});
+};
+
+bootLoader();

Loader/scripts/storage.js

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+// Path: Loader/scripts/storage.js
+
+import { LOADER_INTENT_STORAGE_KEY, LOADER_META_STORAGE_KEY, LOADER_SEEN_COOKIE_MAX_AGE_SECONDS, LOADER_SEEN_COOKIE_NAME } from "./config.js";
+import { collectClientHints } from "./hints.js";
+
+export const persistLoaderState = (intent) => {
+	const payload = {
+		intent,
+		hints: collectClientHints(),
+	};
+
+	try {
+		window.sessionStorage.setItem(LOADER_INTENT_STORAGE_KEY, intent);
+		window.sessionStorage.setItem(LOADER_META_STORAGE_KEY, JSON.stringify(payload));
+	} catch (error) {
+		console.warn("[Loader] Unable to persist bootstrap state.", error);
+	}
+
+	return payload;
+};
+
+export const markLoaderSeen = () => {
+	document.cookie = `${LOADER_SEEN_COOKIE_NAME}=1; Path=/; Max-Age=${LOADER_SEEN_COOKIE_MAX_AGE_SECONDS}; SameSite=Lax`;
+};