Add prototype TimedCache

helpers/timed_cache.js

@@ -0,0 +1,33 @@
+// Keeps items for up to 10 seconds. Items are tagged by a key, which will
+// be used to avoid duplicates.
+export class TimedCache {
+    constructor(maxAge = 10) {
+        this.cache = new Map();
+        this.maxAge = maxAge;
+    }
+
+    addOrUpdate(key, value) {
+        this.cache.set(key, { value: value, age: 0 });
+    }
+
+    tick() {
+        let toRemove = [];
+        this.cache.forEach((val, key) => {
+            val.age += 1;
+            if (val.age > this.maxAge) {
+                toRemove.push(key);
+            }
+        });
+        toRemove.forEach((key) => {
+            this.cache.delete(key)
+        });
+    }
+
+    get() {
+        let result = [];
+        this.cache.forEach((val) => {
+            result.push(val.value);
+        })
+        return result;
+    }
+}