view: add simple input handlers

1 files changed, 39 insertions, 0 deletions

diff --git a/src/view/input/InputHandler.ts b/src/view/input/InputHandler.ts
new file mode 100644
index 0000000..a6f1293
--- /dev/null
+++ b/src/view/input/InputHandler.ts
@@ -0,0 +1,39 @@
+import {Listenable} from '../../util';
+
+export default class InputHandler extends Listenable<[]> {
+	private readonly keys: Set<number> = new Set();
+
+	constructor(relevantKeys: Set<number>) {
+		super();
+
+		window.addEventListener('keydown', (ev) => {
+			if (!relevantKeys.has(ev.keyCode))
+				return;
+
+			ev.preventDefault();
+
+			if (this.keys.has(ev.keyCode))
+				return;
+
+			this.keys.add(ev.keyCode);
+			this.runListeners();
+		});
+
+		window.addEventListener('keyup', (ev) => {
+			if (!relevantKeys.has(ev.keyCode))
+				return;
+
+			ev.preventDefault();
+
+			if (!this.keys.has(ev.keyCode))
+				return;
+
+			this.keys.delete(ev.keyCode);
+			this.runListeners();
+		});
+	}
+
+	public has(key: number): boolean {
+		return this.keys.has(key);
+	}
+}