1 files changed, 37 insertions, 0 deletions
diff --git a/source/js/darkmode.ts b/source/js/darkmode.ts
new file mode 100644
index 0000000..db24d0a
--- /dev/null
+++ b/source/js/darkmode.ts
@@ -0,0 +1,37 @@
+// Darkmode Listener
+enum SystemDarkmodePrefrence {
+    dark = 0,
+    light = 1
+};
+
+class DarkmodeListener {
+    private _mode: SystemDarkmodePrefrence;
+    private _handlers: ((mode: SystemDarkmodePrefrence)=>void)[];
+
+    public constructor() {
+        let darking = window.matchMedia('(prefers-color-scheme: dark)').matches;
+        this._mode = darking ? SystemDarkmodePrefrence.dark : SystemDarkmodePrefrence.light;
+        this._handlers = [];
+        this._listen();
+    }
+
+    private _listen(): void {
+        let media = window.matchMedia('(prefers-color-scheme: dark)');
+        let callback = (event: MediaQueryListEvent) => {
+            let mode = event.matches ? SystemDarkmodePrefrence.dark : SystemDarkmodePrefrence.light;
+            this._handlers.forEach(handler => {
+                handler(mode);
+            });
+            this._mode = mode;
+        };
+        media.addEventListener("change", callback);
+    }
+
+    public add(callback: (mode: SystemDarkmodePrefrence)=>void): void {
+        this._handlers.push(callback);
+    }
+
+    public mode(): SystemDarkmodePrefrence {
+        return this._mode;
+    }
+};