fix: use hasOwnProperty instead of truthiness check for parameter presence in _parse

The check `!params[segments[0].name]` used truthiness to determine if a
parameter key was present, causing falsy-but-valid values like `0` to be
treated as missing. For example, `route('posts.show', { post: 0 })` would
incorrectly wrap params to `{ post: { post: 0 } }` because `!0` is `true`.

Replaced with `!params.hasOwnProperty(segments[0].name)` to check for key
presence instead.

Author: pataar

src/js/Router.js

@@ -263,7 +263,7 @@ export default class Router extends String {
             );
         } else if (
             segments.length === 1 &&
-            !params[segments[0].name] &&
+            !params.hasOwnProperty(segments[0].name) &&
             (params.hasOwnProperty(Object.values(route.bindings)[0]) || params.hasOwnProperty('id'))
         ) {
             // If there is only one template segment and `params` is an object, that object is

tests/js/route.test.js

@@ -593,6 +593,10 @@ describe('route()', () => {
         expect(route('posts.update', 0)).toBe('https://ziggy.dev/posts/0');
     });
 
+    test('can handle an object parameter with a falsy value for the segment name', () => {
+        expect(route('posts.show', { post: 0 })).toBe('https://ziggy.dev/posts/0');
+    });
+
     test('can accept a custom Ziggy configuration object', () => {
         const config = {
             url: 'http://notYourAverage.dev',