fix(history-browser): browser history state not empty on new entries in IE/Edge

Necessary for PR aurelia/router/history-state-consolidation

Author: jwx

src/index.js

@@ -51,7 +51,8 @@ export class BrowserHistory extends History {
     this.root = ('/' + this.options.root + '/').replace(rootStripper, '/');
 
     this._wantsHashChange = this.options.hashChange !== false;
-    this._hasPushState = !!(this.options.pushState && this.history && this.history.pushState);
+    this._hasPushState = !!(this.history && this.history.pushState);
+    this._usePushState = !!(this._hasPushState && this.options.pushState);
 
     // Determine how we check the URL state.
     let eventName;
@@ -72,15 +73,15 @@ export class BrowserHistory extends History {
 
       // If we've started off with a route from a `pushState`-enabled
       // browser, but we're currently in a browser that doesn't support it...
-      if (!this._hasPushState && !atRoot) {
+      if (!this._usePushState && !atRoot) {
         this.fragment = this._getFragment(null, true);
         this.location.replace(this.root + this.location.search + '#' + this.fragment);
         // Return immediately as browser will do redirect to new url
         return true;
 
         // Or if we've started out with a hash-based route, but we're currently
         // in a browser where it could be `pushState`-based instead...
-      } else if (this._hasPushState && atRoot && loc.hash) {
+      } else if (this._usePushState && atRoot && loc.hash) {
         this.fragment = this._getHash().replace(routeStripper, '');
         this.history.replaceState({}, DOM.title, this.root + this.fragment + loc.search);
       }
@@ -151,6 +152,9 @@ export class BrowserHistory extends History {
     // If pushState is available, we use it to set the fragment as a real URL.
     if (this._hasPushState) {
       url = url.replace('//', '/');
+      if (!this._usePushState) {
+        url = '#' + url;
+      }
       this.history[replace ? 'replaceState' : 'pushState']({}, DOM.title, url);
     } else if (this._wantsHashChange) {
       // If hash changes haven't been explicitly disabled, update the hash
@@ -189,7 +193,7 @@ export class BrowserHistory extends History {
     let root;
 
     if (!fragment) {
-      if (this._hasPushState || !this._wantsHashChange || forcePushState) {
+      if (this._usePushState || !this._wantsHashChange || forcePushState) {
         fragment = this.location.pathname + this.location.search;
         root = this.root.replace(trailingSlash, '');
         if (!fragment.indexOf(root)) {
@@ -203,9 +207,12 @@ export class BrowserHistory extends History {
     return '/' + fragment.replace(routeStripper, '');
   }
 
-  _checkUrl(): boolean {
+  _checkUrl(event: any): boolean {
     let current = this._getFragment();
     if (current !== this.fragment) {
+      if (event.type === "popstate") {
+        this.history.replaceState(event.state, null);
+      }
       this._loadUrl();
     }
   }