feat(filters): choose filter in one-hit-wonder decorator

libs/decorators/detect-one-hit-wonder.ts

@@ -1,15 +1,36 @@
 /**
  * Detect one-hit-wonder objects.
  */
+
+import BloomFilter from '../filters/bloom';
+import CuckooFilter from '../filters/cuckoo';
+
+const TYPE_FILTER_MAP = Symbol('TYPE_FILTER_MAP');
+const TYPE_FILTER_BLOOM = Symbol('TYPE_FILTER_BLOOM');
+const TYPE_FILTER_CUCKOO = Symbol('TYPE_FILTER_CUCKOO');
+
 const detectOneHitWonder = (() => {
-    const hitCount = new Map();
+    let filter;
 
-    return (threshold: number = 1) => {
+    return (threshold: number = 1, filterType: symbol = TYPE_FILTER_MAP) => {
         return function (originalMethod: any, _context: ClassMethodDecoratorContext) {
             function replacementMethod(this: any, key: any, value?: any) {
-                let n = hitCount.get(key) ?? 0;
+                const { capacity } = this.stats;
+
+                switch (filterType) {
+                    case TYPE_FILTER_MAP:
+                        filter = new Map();
+                        break;
+                    case TYPE_FILTER_BLOOM:
+                        filter = new BloomFilter(capacity);
+                        break;
+                    case TYPE_FILTER_CUCKOO:
+                        filter = new CuckooFilter(capacity);
+                        break;
+                }
+                let n = filter.get(key) ?? 0;
 
-                hitCount.set(key, ++n);
+                filter.set(key, ++n);
 
                 switch (originalMethod.name) {
                     case 'read':
@@ -27,4 +48,9 @@ const detectOneHitWonder = (() => {
 })();
 
 
+export {
+    TYPE_FILTER_MAP,
+    TYPE_FILTER_BLOOM,
+    TYPE_FILTER_CUCKOO
+};
 export default detectOneHitWonder;

libs/filters/bloom/index.ts

@@ -0,0 +1,18 @@
+class BloomFilter {
+    #store;
+
+    constructor(capacity: number) {
+        if (!Number.isInteger(capacity) || capacity <= 0) {
+            throw new Error('invalid "capacity": positive integer expected');
+        }
+
+        this.#store = new Uint8Array(capacity);
+    }
+
+    set(key: string) {}
+
+    get(key: string) {}
+}
+
+
+export default BloomFilter;

libs/filters/cuckoo/index.ts

@@ -0,0 +1,14 @@
+class CuckooFilter {
+    constructor(capacity: number) {
+        if (!Number.isInteger(capacity) || capacity <= 0) {
+            throw new Error('invalid "capacity": positive integer expected');
+        }
+    }
+
+    set(key: string) {}
+
+    get(key: string) {}
+}
+
+
+export default CuckooFilter;