Function handleHotUpdate

packages/vite/hmr/server/websocket.ts:5059–5458

(ctx)

		},

		async handleHotUpdate(ctx) {
			const { file, server } = ctx;
			if (!wss) {
				return;
			}
			// Graph update for this file change (wrapped to avoid aborting rest of handler)
			try {
				const mod = server.moduleGraph.getModuleById(file) || server.moduleGraph.getModuleById(file + '?vue');
				if (mod) {
					const deps = Array.from(mod.importedModules)
						.map((m) => (m.id || '').replace(/\?.*$/, ''))
						.filter(Boolean);
					const transformed = await server.transformRequest(mod.id!);
					const code = transformed?.code || '';
					upsertGraphModule((mod.id || '').replace(/\?.*$/, ''), code, deps);
				}
			} catch (e) {
				if (verbose) console.warn('[hmr-ws][v2] failed graph update', e);
			}

			const root = server.config.root || process.cwd();
			const srcDir = `${root}/src`;
			const coreDir = `${root}/core`;
			const appDir = `${root}/${APP_ROOT_DIR}`;
			const normalizedFile = file.split(path.sep).join('/');
			const inSrcOrCore = normalizedFile.includes(srcDir) || normalizedFile.includes(coreDir);
			const inApp = normalizedFile.includes(appDir);
			const shouldIgnore = !(inSrcOrCore || inApp);
			if (shouldIgnore) return;
			if (verbose) console.log(`[hmr-ws] Hot update for: ${file}`);

			// Handle CSS updates
			if (file.endsWith('.css')) {
				try {
					let rel = '/' + path.posix.normalize(path.relative(root, file)).split(path.sep).join('/');

					const origin = getServerOrigin(server);
					const msg = {
						type: 'ns:css-updates',
						origin,
						updates: [
							{
								type: 'css-update',
								path: rel,
								acceptedPath: rel,
								timestamp: Date.now(),
							},
						],
					};

					wss.clients.forEach((client) => {
						if (client.readyState === client.OPEN) {
							client.send(JSON.stringify(msg));
						}
					});
				} catch (error) {
					console.warn('[hmr-ws] CSS update failed:', error);
				}