first step on loading a tileset from a script

front/src/Api/Events/TilesetEvent.ts

@@ -0,0 +1,15 @@
+import * as tg from "generic-type-guard";
+
+export const isTilesetEvent =
+    new tg.IsInterface().withProperties({
+        name : tg.isString,
+        imgUrl : tg.isString,
+        tilewidth : tg.isNumber,
+        tileheight : tg.isNumber,
+        margin : tg.isNumber,
+        spacing : tg.isNumber,
+    }).get();
+/**
+ * A message sent from the iFrame to the game to show/hide a layer.
+ */
+export type TilesetEvent = tg.GuardedType<typeof isTilesetEvent>;