Function applyDelta

packages/vite/hmr/client/index.ts:575–658

(payload: any)

}

function applyDelta(payload: any) {
	// If versions are out of sync, request a full graph resync, but still
	// opportunistically queue the changed ids so the client can react once
	// the resync arrives. This is especially important for simple TS flavors
	// where we only need a signal that "something changed" to trigger a
	// resetRootView-driven hot update.
	const currentVersion = getGraphVersion();
	const versionMatches = payload.baseVersion === currentVersion;
	if (!versionMatches) {
		if (VERBOSE) console.warn('[hmr][graph] version mismatch requesting resync', payload.baseVersion, currentVersion);
		try {
			hmrSocket?.send(JSON.stringify({ type: 'ns:hmr-resync-request' }));
		} catch {}
	}
	if (versionMatches) {
		setGraphVersion(payload.newVersion);
	}

	const changed = payload.changed || [];
	switch (__NS_TARGET_FLAVOR__) {
		case 'vue':
			recordVuePayloadChanges(changed, getGraphVersion());
			break;
	}

	(payload.changed || []).forEach((m: any) => {
		if (!m || !m.id) return;
		// Always update the local graph view with the announced module metadata
		graph.set(m.id, { id: m.id, deps: m.deps || [], hash: m.hash || '' });
	});
	(payload.removed || []).forEach((r: string) => {
		graph.delete(r);
	});
	if (VERBOSE) console.log('[hmr][graph] delta applied newVersion', getGraphVersion(), 'changed=', (payload.changed || []).length, 'removed=', (payload.removed || []).length, 'baseVersion=', payload.baseVersion);
	// Queue evaluation of changed modules (placeholder pipeline)
	if (payload.changed?.length) {
		// HARD SUPPRESS: the very first delta (baseVersion 0) commonly includes the app main entry which is already evaluated during bootstrap.
		// Importing it again with a cache-bust often produces a spurious module-not-found (timestamp param treated as distinct file).
		const isInitial = payload.baseVersion === 0;
		// Filter out virtual helper ids (e.g. '\0plugin-vue:export-helper') which we do not evaluate directly
		const realIds = payload.changed.map((c: any) => c.id).filter((id: string) => !/^\0|^\/\0|plugin-vue:export-helper/.test(id));
		// Proactively prefetch core/src deps for any changed .vue SFCs (before registry update triggers reset)
		try {
			for (const entry of payload.changed || []) {
				if (!entry || !/\.vue$/i.test(entry.id)) continue;
				const deps: string[] = Array.isArray(entry.deps) ? entry.deps : [];
				const prefetchTargets = deps.filter((d) => /^\//.test(d) && !/node_modules/.test(d) && !/\.vue$/i.test(d));
				if (prefetchTargets.length && VERBOSE) console.log('[hmr][prefetch] SFC deps', entry.id, '->', prefetchTargets);
				for (const dep of prefetchTargets) {
					const norm = normalizeSpec(dep);
					// Skip if we already wrote it (basic heuristic: moduleFetchCache has it or path exists in Documents/_ns_hmr)
					if (moduleFetchCache.has(norm)) continue;
					// Fire and forget; ensure rejection does not break HMR pipeline
					requestModuleFromServer(norm).catch(() => {});
				}
			}
		} catch (e) {
			if (VERBOSE) console.warn('[hmr][prefetch] failed', e);