get rid of flow hack

Author: yyx990803

package.json

@@ -49,7 +49,7 @@
     "eslint-plugin-html": "^1.5.2",
     "express": "^4.14.0",
     "express-urlrewrite": "^1.2.0",
-    "flow-bin": "^0.32.0",
+    "flow-bin": "^0.33.0",
     "gitbook-plugin-edit-link": "^2.0.2",
     "gitbook-plugin-github": "^2.0.0",
     "jasmine": "2.4.1",

src/history/base.js

@@ -108,14 +108,6 @@ export class History {
       hook && hook(route, prev)
     })
   }
-
-  /**
-   * Dummy method to make flow happy...
-   * otherwise it won't let me call `this.history.onHashChange`
-   * inside a `switch case`...
-   * Advices on how to remove this method are much appreciated.
-   */
-  onHashChange () {}
 }
 
 function normalizeBase (base: ?string): string {

src/index.js

@@ -65,20 +65,19 @@ export default class VueRouter {
 
     this.app = app
 
-    switch (this.mode) {
-      case 'history':
-        this.history.transitionTo(getLocation(this.history.base))
-        break
-      case 'hash':
-        this.history.transitionTo(getHash(), () => {
-          window.addEventListener('hashchange', () => {
-            this.history.onHashChange()
-          })
+    const history = this.history
+
+    if (history instanceof HTML5History) {
+      history.transitionTo(getLocation(history.base))
+    } else if (history instanceof HashHistory) {
+      history.transitionTo(getHash(), () => {
+        window.addEventListener('hashchange', () => {
+          history.onHashChange()
         })
-        break
+      })
     }
 
-    this.history.listen(route => {
+    history.listen(route => {
       this.app._route = route
     })
   }