error if routes clash - fixes #33

Author: Rich-Harris

lib/utils/create_routes.js

@@ -1,7 +1,7 @@
 const path = require('path');
 
 module.exports = function create_matchers(files) {
-	return files
+	const routes = files
 		.map(file => {
 			if (/(^|\/|\\)_/.test(file)) return;
 
@@ -47,9 +47,31 @@ module.exports = function create_matchers(files) {
 		})
 		.filter(Boolean)
 		.sort((a, b) => {
-			return (
-				(a.dynamic.length - b.dynamic.length) || // match static paths first
-				(b.parts.length - a.parts.length) // match longer paths first
-			);
+			let same = true;
+
+			for (let i = 0; true; i += 1) {
+				const a_part = a.parts[i];
+				const b_part = b.parts[i];
+
+				if (!a_part && !b_part) {
+					if (same) throw new Error(`The ${a.file} and ${b.file} routes clash`);
+					return 0;
+				}
+
+				if (!a_part) return 1;
+				if (!b_part) return -1;
+
+				const a_is_dynamic = a_part[0] === '[';
+				const b_is_dynamic = b_part[0] === '[';
+
+				if (a_is_dynamic === b_is_dynamic) {
+					if (!a_is_dynamic) same = false;
+					continue;
+				}
+
+				return a_is_dynamic ? 1 : -1;
+			}
 		});
+
+	return routes;
 }

test/unit/create_routes.test.js

@@ -5,15 +5,17 @@ const create_routes = require('../../lib/utils/create_routes.js');
 
 describe('create_routes', () => {
 	it('sorts routes correctly', () => {
-		const routes = create_routes(['index.html', 'about.html', '[wildcard].html', 'post/[id].html']);
+		const routes = create_routes(['index.html', 'about.html', '[wildcard].html', 'post/foo.html', 'post/[id].html', 'post/bar.html']);
 
 		assert.deepEqual(
 			routes.map(r => r.file),
 			[
-				'about.html',
-				'index.html',
+				'post/foo.html',
+				'post/bar.html',
 				'post/[id].html',
-				'[wildcard].html'
+				'about.html',
+				'[wildcard].html',
+				'index.html'
 			]
 		);
 	});
@@ -48,4 +50,25 @@ describe('create_routes', () => {
 			]
 		);
 	});
+
+	it('matches /foo/:bar before /:baz/qux', () => {
+		const a = create_routes(['foo/[bar].html', '[baz]/qux.html']);
+		const b = create_routes(['[baz]/qux.html', 'foo/[bar].html']);
+
+		assert.deepEqual(
+			a.map(r => r.file),
+			['foo/[bar].html', '[baz]/qux.html']
+		);
+
+		assert.deepEqual(
+			b.map(r => r.file),
+			['foo/[bar].html', '[baz]/qux.html']
+		);
+	});
+
+	it('fails if routes are indistinguishable', () => {
+		assert.throws(() => {
+			create_routes(['[foo].html', '[bar]/index.html']);
+		}, /The \[foo\].html and \[bar\]\/index.html routes clash/);
+	});
 });