refactor a bit, fix typing error

src/generators/Generator.ts

@@ -13,7 +13,8 @@ import annotateWithScopes from '../utils/annotateWithScopes';
 import clone from '../utils/clone';
 import DomBlock from './dom/Block';
 import SsrBlock from './server-side-rendering/Block';
-import extractSelectors from './extractSelectors';
+import { walkRules } from '../utils/css';
+import Selector from './Selector';
 import { Node, Parsed, CompileOptions } from '../interfaces';
 
 const test = typeof global !== 'undefined' && global.__svelte_test;
@@ -41,7 +42,7 @@ export default class Generator {
 	cssId: string;
 	usesRefs: boolean;
 
-	selectors: any[]; // TODO how to indicate it takes `(Node[]) => boolean` functions?
+	selectors: Selector[];
 
 	importedNames: Set<string>;
 	aliases: Map<string, string>;
@@ -74,12 +75,21 @@ export default class Generator {
 		this.expectedProperties = new Set();
 
 		this.code = new MagicString(source);
+		this.usesRefs = false;
+
+		// styles
 		this.cascade = options.cascade !== false; // TODO remove this option in v2
 		this.css = parsed.css ? processCss(parsed, this.code, this.cascade) : null;
 		this.cssId = parsed.css ? `svelte-${parsed.hash}` : '';
-		this.usesRefs = false;
+		this.selectors = [];
 
-		this.selectors = extractSelectors(parsed.css);
+		if (parsed.css) {
+			walkRules(parsed.css.children, node => {
+				node.selector.children.forEach((child: Node) => {
+					this.selectors.push(new Selector(child));
+				});
+			});
+		}
 
 		// allow compiler to deconflict user's `import { get } from 'whatever'` and
 		// Svelte's builtin `import { get, ... } from 'svelte/shared.ts'`;

src/generators/Selector.ts

@@ -1,21 +1,19 @@
 import { walkRules } from '../utils/css';
 import { Node } from '../interfaces';
 
-export default function extractSelectors(css: Node) :Node[] {
+export default class Selector {
-	if (!css) return [];
+	node: Node;
+	parts: Node[];
+	used: boolean;
 
-	const selectors = [];
+	constructor(node: Node) {
+		this.node = node;
 
-	walkRules(css.children, node => {
-		node.selector.children.forEach(processSelector);
-	});
-
-	function processSelector(selector: Node) {
 		// take trailing :global(...) selectors out of consideration
-		let i = selector.children.length;
+		let i = node.children.length;
 		while (i > 2) {
-			const last = selector.children[i-1];
+			const last = node.children[i-1];
-			const penultimate = selector.children[i-2];
+			const penultimate = node.children[i-2];
 
 			if (last.type === 'PseudoClassSelector' && last.name === 'global') {
 				i -= 2;
@@ -24,24 +22,21 @@ export default function extractSelectors(css: Node) :Node[] {
 			}
 		}
 
-		const parts = selector.children.slice(0, i);
+		this.parts = node.children.slice(0, i);
+
+		this.used = false; // TODO use this! warn on unused selectors
+	}
 
-		selectors.push({
+	apply(node: Node, stack: Node[]) {
-			used: false, // TODO use this! warn on unused selectors
+		const applies = selectorAppliesTo(this.parts, node, stack.slice());
-			apply: (node: Node, stack: Node[]) => {
-				const applies = selectorAppliesTo(parts, node, stack.slice());
 
 		if (applies) {
 			// add svelte-123xyz attribute to outermost and innermost
 			// elements — no need to add it to intermediate elements
 			node._needsCssAttribute = true;
-					if (stack[0] && selector.children.find(isDescendantSelector)) stack[0]._needsCssAttribute = true;
+			if (stack[0] && this.node.children.find(isDescendantSelector)) stack[0]._needsCssAttribute = true;
 		}
 	}
-		});
-	}
-
-	return selectors;
 }
 
 function isDescendantSelector(selector: Node) {