TypeScript support: don't try to compile templates

package.json

@@ -22,7 +22,8 @@
     "http-link-header": "^1.0.2",
     "shimport": "^1.0.1",
     "sourcemap-codec": "^1.4.6",
-    "string-hash": "^1.1.3"
+    "string-hash": "^1.1.3",
+    "tippex": "^3.0.0"
   },
   "devDependencies": {
     "@types/mocha": "^5.2.7",

src/core/create_manifest_data.ts

@@ -1,9 +1,26 @@
 import * as fs from 'fs';
 import * as path from 'path';
-import svelte from 'svelte/compiler';
+import * as tippex from 'tippex';
 import { Page, PageComponent, ServerRoute, ManifestData } from '../interfaces';
 import { posixify, reserved_words } from '../utils';
 
+export function template_has_preload(content: string) {
+	const regex = /<script.*?context="module".*?>([^]*?)<\/script>/g;
+	let m;
+	while ((m = regex.exec(content)) !== null) {
+		// This is necessary to avoid infinite loops with zero-width matches
+		if (m.index === regex.lastIndex) {
+			regex.lastIndex++;
+		}
+
+		const source_minus_comments = tippex.erase(m[1]);
+		if (/export\s+.*?preload/.test(source_minus_comments)) {
+			return true;
+		}
+	}
+	return false;
+}
+
 export default function create_manifest_data(cwd: string, extensions: string = '.svelte .html'): ManifestData {
 
 	const component_extensions = extensions.split(' ');
@@ -13,30 +30,24 @@ export default function create_manifest_data(cwd: string, extensions: string = '
 		throw new Error(`As of Sapper 0.21, the routes/ directory should become src/routes/`);
 	}
 
-	function has_preload(file: string) {
-		const source = fs.readFileSync(path.join(cwd, file), 'utf-8');
-
-		if (/preload/.test(source)) {
-			try {
-				const { vars } = svelte.compile(source.replace(/<style\b[^>]*>[^]*?<\/style>/g, ''), { generate: false });
-				return vars.some((variable: any) => variable.module && variable.export_name === 'preload');
-			} catch (err) {}
-		}
-
-		return false;
+	function file_has_preload(file: string) {
+		const content = fs.readFileSync(path.join(cwd, file), 'utf-8');
+		return template_has_preload(content);
 	}
 
 	function find_layout(file_name: string, component_name: string, dir: string = '') {
 		const ext = component_extensions.find((ext) => fs.existsSync(path.join(cwd, dir, `${file_name}${ext}`)));
 		const file = posixify(path.join(dir, `${file_name}${ext}`))
 
-		return ext
-			? {
+		if (!ext) {
+			return null;
+		}
+
+		return {
 				name: component_name,
 				file: file,
-				has_preload: has_preload(file)
-			}
-			: null;
+				has_preload: file_has_preload(file)
+			};
 	}
 
 	const components: PageComponent[] = [];
@@ -162,7 +173,7 @@ export default function create_manifest_data(cwd: string, extensions: string = '
 				const component = {
 					name: get_slug(item.file),
 					file: item.file,
-					has_preload: has_preload(item.file)
+					has_preload: file_has_preload(item.file)
 				};
 
 				components.push(component);

test/unit/create_manifest_data/test.ts

@@ -1,6 +1,65 @@
 import * as path from 'path';
 import * as assert from 'assert';
-import create_manifest_data from '../../../src/core/create_manifest_data';
+import create_manifest_data, { template_has_preload } from '../../../src/core/create_manifest_data';
+
+describe('template_has_preload', () => {
+	it('should detect async preload', () => {
+		const source = `
+			<script context="module">
+				export async function preload() {
+					const client = getClient();
+					let response = await client.query({ query: GET_POSTS });
+					let posts = response.data.getPosts;
+					return { posts };
+				}
+			</script>
+		`;
+		assert.ok(template_has_preload(source));
+	});
+
+	it('should detect preload in composed function', () => {
+		const source = `
+			<script context="module">
+				export const preload = verifyUser(catchErrors(function () { console.log('test'); }));
+			</script>
+		`;
+		assert.ok(template_has_preload(source));
+	});
+
+	it('should detect reusable preload functions', () => {
+		const source = `
+			<script context="module">
+				export { preload } from './userData'
+			</script>
+		`;
+		assert.ok(template_has_preload(source));
+	});
+
+	it('should not detect preload functions in single line comment', () => {
+		const source = `
+			<script context="module">
+				//export { preload } from './userData'
+			</script>
+		`;
+		assert.ok(!template_has_preload(source));
+	});
+
+	it('should not detect preload functions in comment block', () => {
+		const source = `
+			<script context="module">
+				/*
+				export async function preload() {
+					const client = getClient();
+					let response = await client.query({ query: GET_POSTS });
+					let posts = response.data.getPosts;
+					return { posts };
+				}
+				*/
+			</script>
+		`;
+		assert.ok(!template_has_preload(source));
+	});
+});
 
 describe('manifest_data', () => {
 	it('creates routes', () => {