add class for keyboard events

src/common/index.js

@@ -1,3 +1,4 @@
 export { backgroundLayout } from "./layouts";
 export { makeDragable, makeUnDragable } from "./dragAndDrop";
 export { getIntersection } from "./helpers";
+export { KeyBoardListener } from "./keyBoardEvents";

src/common/keyBoardEvents.js

@@ -0,0 +1,46 @@
+export class KeyBoardListener {
+    static _listenersKeyUp = {};
+    static _listenersKeyDown = {};
+    static ready = false;
+    static _listenCount = 0;
+    static init() {
+        document.addEventListener("keydown", (event) => {
+            for (const listener of Object.values(
+                KeyBoardListener._listenersKeyDown,
+            )) {
+                listener(event);
+            }
+        });
+        document.addEventListener("keyup", (event) => {
+            for (const listener of Object.values(
+                KeyBoardListener._listenersKeyUp,
+            )) {
+                listener(event);
+            }
+        });
+
+        KeyBoardListener.ready = true;
+    }
+
+    /* return id used to remove the listener */
+    static onKeyDown(callback) {
+        const id = KeyBoardListener._listenCount++;
+        KeyBoardListener._listenersKeyDown[id] = callback;
+        return id;
+    }
+
+    static offKeyDown(id) {
+        delete KeyBoardListener._listenersKeyDown[id];
+    }
+
+    /* return id used to remove the listener */
+    static onKeyUp(callback) {
+        const id = KeyBoardListener._listenCount++;
+        KeyBoardListener._listenersKeyUp[id] = callback;
+        return id;
+    }
+
+    static offKeyUp(id) {
+        delete KeyBoardListener._listenersKeyUp[id];
+    }
+}