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frontend/src/composables/ticker.ts

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+import { onMounted, onUnmounted, ref, shallowRef } from 'vue'
+
+export function useNow(update_ms: number) {
+    const handle = shallowRef<number | undefined>(undefined);
+    const now = ref(Date.now());
+
+    onMounted(() => {
+        handle.value = setInterval(() => {
+            now.value = Date.now();
+        }, update_ms);
+    });
+    onUnmounted(() => {
+        if (handle.value) {
+            clearInterval(handle.value);
+        }
+    });
+
+    return now;
+}