Fix compile errors in TS code

These errors don't actually appear until bazel is upgraded.

Change-Id: I57886ce83432c4083f2d03bea60c658dd4f61ddb
diff --git a/tsconfig.json b/tsconfig.json
index 91093d3..d330268 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -2,7 +2,9 @@
   "compilerOptions": {
     "experimentalDecorators": true,
     "strict": true,
-    "noImplicitAny": false
+    "noImplicitAny": false,
+    "target": "es6",
+    "lib": ["es6", "dom"]
   },
   "bazelOptions": {
     "workspaceName": "971-Robot-Code"
diff --git a/y2019/vision/server/www/main.ts b/y2019/vision/server/www/main.ts
index 5647d7b..9e90563 100644
--- a/y2019/vision/server/www/main.ts
+++ b/y2019/vision/server/www/main.ts
@@ -16,7 +16,7 @@
   private targetX = 0;
   private targetY = 0;
   private targetTheta = 0;
-  private cameraFrames : Frame[];
+  private cameraFrames : Frame[] = [];
 
   private wrist: number = -1;
   private elevator: number = -1;
@@ -42,12 +42,13 @@
 
     const server = location.host;
     this.initWebSocket(server);
-    window.requestAnimationFrame(() => this.draw(ctx));
+    if (!!ctx) {
+      window.requestAnimationFrame(() => this.draw(ctx));
+    }
   }
 
   initWebSocket(server: string): void {
     const socket = new WebSocket(`ws://${server}/ws`);
-    this.cameraFrames = [];
 
     socket.addEventListener('message', (event) => {
       const j = JSON.parse(event.data);