InputHandler: prevent default for relavant keys

src/app.ts

@@ -11,6 +11,16 @@ import MapContext from './control/MapContext';
 import MapData from './model/MapData';
 import InputHandler from './view/InputHandler';
 
+import * as util from './util';
+
+
+var relevantKeys = [
+        InputHandler.Up,
+        InputHandler.Right,
+        InputHandler.Down,
+        InputHandler.Left,
+];
+
 
 var mapContext: MapContext;
 
@@ -19,7 +29,7 @@ window.onload = () => {
 
         xhr.onload = function() {
                 var mapDef = new MapData(JSON.parse(this.responseText));
-                var inputHandler = new InputHandler();
+                var inputHandler = new InputHandler(util.numberArrayToMap(relevantKeys));
                 mapContext = new MapContext(mapDef, inputHandler);
         }
 

src/util.ts

@@ -11,3 +11,12 @@ export function mapPromises<T>(promises: {[key: string]: Promise<T>}): Promise<{
 
         return Promise.all(p).then(() => ret);
 }
+
+export function numberArrayToMap(arr: number[]): {[key: number]: boolean} {
+        var ret: {[key: number]: boolean} = {};
+
+        for (let v of arr)
+                ret[v] = true;
+
+        return ret;
+}

src/view/InputHandler.ts

@@ -13,8 +13,13 @@ class InputHandler {
                 this.listeners.forEach(l => l());
         }
 
-        constructor() {
+        constructor(private relevantKeys: {[key: number]: boolean}) {
                 window.addEventListener('keydown', (ev) => {
+                        if (!relevantKeys[ev.keyCode])
+                                return;
+
+                        ev.preventDefault();
+
                         if (!this.keys[ev.keyCode]) {
                                 this.keys[ev.keyCode] = true;
                                 this.callListeners();
@@ -22,6 +27,11 @@ class InputHandler {
                 });
 
                 window.addEventListener('keyup', (ev) => {
+                        if (!relevantKeys[ev.keyCode])
+                                return;
+
+                        ev.preventDefault();
+
                         if (this.keys[ev.keyCode]) {
                                 delete this.keys[ev.keyCode];
                                 this.callListeners();