added dismount lifecycle

src/lifecycle.ts

@@ -0,0 +1,36 @@
+const CLEANUP_KEY = Symbol('cleanup_func');
+
+export function onDismount(el: Node, fn: () => void) {
+  const element = el as any;
+  if (!element[CLEANUP_KEY]) {
+    element[CLEANUP_KEY] = [];
+  }
+
+  element[CLEANUP_KEY].push(fn);
+}
+
+const observer = new MutationObserver((mutations) => {
+  mutations.forEach(mutation => {
+    mutation.removedNodes.forEach(node => {
+      deepCleanup(node);
+    })
+  })
+})
+
+observer.observe(document.body, {
+  childList: true,
+  subtree: true
+});
+
+function deepCleanup(node: Node) {
+  const el = node as any;
+
+  if (el[CLEANUP_KEY]) {
+    el[CLEANUP_KEY].forEach((fn: () => void) => fn());
+    el[CLEANUP_KEY] = null;
+  }
+
+  if (node.hasChildNodes()) {
+    node.childNodes.forEach(deepCleanup)
+  }
+}

src/router.ts

@@ -6,9 +6,11 @@ export interface RouteContext {
   query: QueryParams
 }
 
-type NextFunction = () => void;
-type RouteHandler = (ctx: RouteContext) => void;
-type RouteGuard = (ctx: RouteContext, next: NextFunction) => void;
+export type NextFunction = () => void;
+export type RouteHandler = (ctx: RouteContext) => HTMLElement;
+export type RouteGuard = (ctx: RouteContext, next: NextFunction) => void;
+
+export type LayoutHandler = () => { view: HTMLElement, slot: HTMLElement }
 
 interface Route {
   path: string;
@@ -16,6 +18,7 @@ interface Route {
   keys: string[],
   handler: RouteHandler;
   guards: RouteGuard[];
+  layout?: LayoutHandler
 }
 
 export class Router {
@@ -24,6 +27,9 @@ export class Router {
   private rootElement: HTMLElement | null = null;
   private isTransitioning = false;
 
+  private currentLayout: LayoutHandler | null = null;
+  private currentSlot: HTMLElement | null = null;
+
   private static instance: Router | null = null;
 
   constructor(rootId: string) {
@@ -41,7 +47,7 @@ export class Router {
     }
   }
 
-  public addRoute(path: string, handler: RouteHandler, guards: RouteGuard[] = []) {
+  public addRoute(path: string, handler: RouteHandler, guards: RouteGuard[] = [], layout?: LayoutHandler) {
     const keys: string[] = [];
     const regexpPath = path.replace(/:(\w+)/g, (_, key) => {
       keys.push(key);
@@ -51,7 +57,7 @@ export class Router {
     this.routes.push({
       path,
       regex: new RegExp(`^${regexpPath}$`),
-      keys, handler, guards
+      keys, handler, guards, layout
     })
   }
 
@@ -76,9 +82,33 @@ export class Router {
         const ctx: RouteContext = { params, query };
 
         this.runGuards(route.guards, ctx, () => {
+          const pageElement = route.handler(ctx);
+
+          const layoutChanged = route.layout !== this.currentLayout;
+          const transitionTarget = layoutChanged ? this.rootElement : this.currentSlot
+
+
           this.performTransition(() => {
-            route.handler(ctx);
-          })
+            if (layoutChanged) {
+              if (route.layout) {
+                const { view, slot } = route.layout();
+                this.rootElement!.innerHTML = '';
+                this.rootElement!.appendChild(view);
+                this.currentSlot = slot;
+                this.currentLayout = route.layout;
+              } else {
+                this.rootElement!.innerHTML = '';
+                this.currentSlot = this.rootElement;
+                this.currentLayout = null;
+              }
+            }
+
+            if (this.currentSlot) {
+              this.currentSlot.innerHTML = ''
+              this.currentSlot.appendChild(pageElement);
+            }
+
+          }, transitionTarget)
         });
         return;
       }
@@ -100,14 +130,15 @@ export class Router {
     next();
   }
 
-  private performTransition(updateDomFn: () => void) {
-    if (!this.rootElement) {
+  private performTransition(updateDomFn: () => void, targetElement: HTMLElement | null) {
+    const el = targetElement || this.rootElement;
+
+    if (!el) {
       updateDomFn();
       return;
     }
 
     this.isTransitioning = true;
-
     this.rootElement.classList.add('fading');
 
     setTimeout(() => {