Add mediaquery selector

src/main.js

@@ -25,6 +25,12 @@ class StateSwitch extends LitElement {
     if(config.entity === 'hash') {
       window.addEventListener("location-changed", () => this.updated(new Map()));
     }
+    if(config.entity === 'mediaquery') {
+      for(const q in this.cards) {
+        console.log("Register " + q);
+        window.matchMedia(q).addEventListener("change", this.update_state.bind(this));
+      }
+    }
   }
 
   update_state() {
@@ -42,6 +48,17 @@ class StateSwitch extends LitElement {
       case "hash":
         newstate = location.hash.substr(1);
         break;
+      case "mediaquery":
+        for(const q in this.cards) {
+          console.log("Check " + q);
+          console.log(window.matchMedia(q));
+          if(window.matchMedia(q).matches) {
+            newstate = q;
+            console.log(newstate);
+            break;
+          }
+        }
+        break;
       default:
         newstate = this.hass.states[this._config.entity];
         newstate = newstate ? newstate.state : undefined;