feat(RouterEngine)!: Rename noMatches to fallback and make resolvedHash public

AGENTS.md

@@ -52,7 +52,7 @@ Where `RouteInfo` contains:
 
 #### Reactive Properties
 - `routeStatus`: Per-route match status and extracted parameters
-- `noMatches`: Boolean indicating NO routes matched (excluding `ignoreForFallback` routes)
+- `fallback`: Boolean indicating NO routes matched (excluding `ignoreForFallback` routes)
 
 ### Component Architecture
 
@@ -72,12 +72,12 @@ universe they belong to.
 #### Fallback Component
 - Shows content when no routes match
 - Props:
-  - `when?: WhenPredicate`: Override default `noMatches` behavior
+  - `when?: WhenPredicate`: Override default `fallback` behavior
   - `children`: Content snippet
 
 Render logic:
 ```svelte
-{#if (router && when?.(router.routeStatus, router.noMatches)) || (!when && router?.noMatches)}
+{#if (router && when?.(router.routeStatus, router.fallback)) || (!when && router?.fallback)}
   {@render children?.(router.state, router.routeStatus)}
 {/if}
 ```
@@ -224,8 +224,8 @@ test("Should hide content when routes match.", () => {
 });
 
 // ❌ Bad - Test internal implementation
-test("Should call router.noMatches.", () => {
-    const spy = vi.spyOn(router, 'noMatches');
+test("Should call router.fallback.", () => {
+    const spy = vi.spyOn(router, 'fallback');
     render(Component, { props, context });
     expect(spy).toHaveBeenCalled(); // Testing implementation detail
 });
@@ -240,7 +240,7 @@ test("Component renders when condition is met.", () => {
 });
 
 // ✅ Router tests focus on router logic (separate file)
-test("Router calculates noMatches correctly.", () => {
+test("Router calculates fallback correctly.", () => {
     // Test router's internal logic
 });
 ```
@@ -691,7 +691,7 @@ test("Should react to state changes.", () => {
 **Purpose**: Render content when no routes match, with override capability
 
 **Key behaviors to test**:
-1. Shows when `router.noMatches` is true
+1. Shows when `router.fallback` is true
 2. Hides when routes are matching  
 3. Respects `when` predicate override
 4. Works across all routing universes

src/lib/Fallback/Fallback.svelte

@@ -53,8 +53,8 @@
 		/**
 		 * Renders the children of the component.
 		 *
-		 * This rendering is conditioned to the parent router engine's `noMatches` property being `true`.  This means
-		 * that the children will only be rendered when no route matches the current location.
+		 * This rendering is conditioned to the parent router engine's `fallback` property being `true`.  This means
+		 * that the children will only be rendered when no routes match the current location.
 		 * @param context The component's context available to children.
 		 */
 		children?: Snippet<[RouterChildrenContext]>;
@@ -68,6 +68,6 @@
 	const router = getRouterContext(resolvedHash);
 </script>
 
-{#if (router && when?.(router.routeStatus, router.noMatches)) || (!when && router?.noMatches)}
+{#if (router && when?.(router.routeStatus, router.fallback)) || (!when && router?.fallback)}
 	{@render children?.({ state: router.state, rs: router.routeStatus })}
 {/if}

src/lib/Fallback/README.md

@@ -3,7 +3,7 @@
 The `Fallback` component can be thought about as a `Route` component that only render its children if there are no 
 other routes in the parent router engine that match.
 
-Internally, it checks the parent router engine's `noMatches` value, which is a reactive value calculated when all other 
+Internally, it checks the parent router engine's `fallback` value, which is a reactive value calculated when all other 
 route status data is calculated.
 
 ## Props

src/lib/kernel/RouterEngine.svelte.test.ts

@@ -666,13 +666,13 @@ ROUTING_UNIVERSES.forEach(universe => {
             });
         });
 
-        describe('noMatches', () => {
+        describe('fallback', () => {
             test("Should be true whenever there are no routes registered.", () => {
                 // Act.
                 const router = new RouterEngine({ hash: universe.hash });
 
                 // Assert.
-                expect(router.noMatches).toBe(true);
+                expect(router.fallback).toBe(true);
             });
 
             test("Should be true whenever there are no matching routes.", () => {
@@ -686,7 +686,7 @@ ROUTING_UNIVERSES.forEach(universe => {
                 };
 
                 // Assert.
-                expect(router.noMatches).toBe(true);
+                expect(router.fallback).toBe(true);
             });
 
             test.each([
@@ -714,7 +714,7 @@ ROUTING_UNIVERSES.forEach(universe => {
                 addRoutes(router, { matching: routeCount, nonMatching: nonMatchingCount });
 
                 // Assert.
-                expect(router.noMatches).toBe(false);
+                expect(router.fallback).toBe(false);
             });
 
             test.each([
@@ -732,7 +732,7 @@ ROUTING_UNIVERSES.forEach(universe => {
                 });
 
                 // Assert.
-                expect(router.noMatches).toBe(true);
+                expect(router.fallback).toBe(true);
             });
         });
     });

src/lib/kernel/RouterEngine.svelte.ts

@@ -47,7 +47,7 @@ export class RouterEngine {
     #routeHelper;
     #cleanup = false;
     #parent: RouterEngine | undefined;
-    #resolvedHash: Hash;
+    resolvedHash: Hash;
     /**
      * Gets or sets the router's identifier.  This is displayed by the `RouterTracer` component.
      */
@@ -86,17 +86,17 @@ export class RouterEngine {
 
     #routeStatusData = $derived.by(() => {
         const routeStatus = {} as Record<string, RouteStatus>;
-        let noMatches = true;
+        let fallback = true;
         for (let routeKey of Object.keys(this.routes)) {
             const pattern = this.#routePatterns.get(routeKey)!;
             const [match, routeParams] = this.#routeHelper.testRoute(pattern);
-            noMatches = noMatches && (pattern.ignoreForFallback ? true : !match);
+            fallback = fallback && (pattern.ignoreForFallback ? true : !match);
             routeStatus[routeKey] = {
                 match,
                 routeParams,
             };
         }
-        return [routeStatus, noMatches] as const;
+        return [routeStatus, fallback] as const;
     });
     /**
      * Gets a a record of route statuses where the keys are the route keys, and the values are 
@@ -105,9 +105,9 @@ export class RouterEngine {
     routeStatus = $derived(this.#routeStatusData[0]);
     /**
      * Gets a boolean value that indicates whether the current URL matches none of the route 
-     * patterns.
+     * patterns, therefore enabling fallback behavior.
      */
-    noMatches = $derived(this.#routeStatusData[1]);
+    fallback = $derived(this.#routeStatusData[1]);
     /**
      * Initializes a new instance of this class with the specified options.
      */
@@ -121,24 +121,24 @@ export class RouterEngine {
             throw new Error("The routing library hasn't been initialized.  Execute init() before creating routers.");
         }
         if (isRouterEngine(parentOrOpts)) {
-            this.#resolvedHash = parentOrOpts.#resolvedHash;
+            this.resolvedHash = parentOrOpts.resolvedHash;
             this.#parent = parentOrOpts;
         }
         else {
             this.#parent = parentOrOpts?.parent;
-            this.#resolvedHash = this.#parent && parentOrOpts?.hash === undefined ? this.#parent.#resolvedHash : resolveHashValue(parentOrOpts?.hash);
-            if (this.#parent && this.#resolvedHash !== this.#parent.#resolvedHash) {
+            this.resolvedHash = this.#parent && parentOrOpts?.hash === undefined ? this.#parent.resolvedHash : resolveHashValue(parentOrOpts?.hash);
+            if (this.#parent && this.resolvedHash !== this.#parent.resolvedHash) {
                 throw new Error("The parent router's hash mode must match the child router's hash mode.");
             }
-            if (routingOptions.hashMode === 'multi' && this.#resolvedHash && typeof this.#resolvedHash !== 'string') {
+            if (routingOptions.hashMode === 'multi' && this.resolvedHash && typeof this.resolvedHash !== 'string') {
                 throw new Error("The specified hash value is not valid for the 'multi' hash mode.  Either don't specify a hash for path routing, or correct the hash value.");
             }
-            if (routingOptions.hashMode !== 'multi' && typeof this.#resolvedHash === 'string') {
+            if (routingOptions.hashMode !== 'multi' && typeof this.resolvedHash === 'string') {
                 throw new Error("A hash path ID was given, but is only allowed when the library's hash mode has been set to 'multi'.");
             }
         }
-        assertAllowedRoutingMode(this.#resolvedHash);
-        this.#routeHelper = new RouteHelper(this.#resolvedHash);
+        assertAllowedRoutingMode(this.resolvedHash);
+        this.#routeHelper = new RouteHelper(this.resolvedHash);
         if (traceOptions.routerHierarchy) {
             registerRouter(this);
             this.#cleanup = true;
@@ -158,7 +158,7 @@ export class RouterEngine {
      * This is a shortcut for `location.state`.
      */
     get state() {
-        return location.getState(this.#resolvedHash);
+        return location.getState(this.resolvedHash);
     }
     /**
      * Gets or sets the router's base path.

src/lib/types.ts

@@ -428,10 +428,10 @@ export type ActiveState = {
  * Defines the type of function accepted by the `Fallback` component via its `when` property.
  * 
  * @param routeStatus The current route status data from the parent router.
- * @param noMatches The value that the parent router has calculated as per standard fallback logic.
+ * @param fallback The value that the parent router has calculated as per standard fallback logic.
  * @returns `true` if the fallback content should be shown; `false` to prevent content from being shown.
  */
-export type WhenPredicate = (routeStatus: Record<string, RouteStatus>, noMatches: boolean) => boolean;
+export type WhenPredicate = (routeStatus: Record<string, RouteStatus>, fallback: boolean) => boolean;
 
 /**
  * Defines the shape of logger objects that can be given to this library during initialization.