Support Svelte 3

fixes #546, #551, #552, #554

runtime/src/server/middleware/mime.ts

@@ -0,0 +1,20 @@
+import mime_raw from './mime-types.md';
+
+const map: Map<string, string> = new Map();
+
+mime_raw.split('\n').forEach((row: string) => {
+	const match = /(.+?)\t+(.+)/.exec(row);
+	if (!match) return;
+
+	const type = match[1];
+	const extensions = match[2].split(' ');
+
+	extensions.forEach(ext => {
+		map.set(ext, type);
+	});
+});
+
+export function lookup(file: string) {
+	const match = /\.([^\.]+)$/.exec(file);
+	return match && map.get(match[1]);
+}