feat(rr-cache): add hit ratio measurement

zhibirc · Nov 30, 2023 · 5e52778 · 5e52778
1 parent 39547fc
commit 5e52778
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Showing 4 changed files with 26 additions and 8 deletions.
diff --git a/rr-cache/index.d.ts b/rr-cache/index.d.ts
@@ -2,10 +2,11 @@ type TStats = {
     size: number;
     capacity: number;
     locked: boolean;
+    hitRatio: number;
 };
 interface IRRCache {
     get stats(): TStats;
-    set locked(state: boolean);
+    set lock(state: boolean);
     read: (key: any) => any;
     add: (key: any, value: any) => void;
     has: (key: any) => boolean;
@@ -27,8 +28,9 @@ declare class RRCache implements IRRCache {
         size: number;
         capacity: number;
         locked: boolean;
+        hitRatio: number;
     };
-    set locked(state: boolean);
+    set lock(state: boolean);
     /**
      * Read value stored in cache by assosiated key.
      * @param {*} key - cache record's key

diff --git a/rr-cache/index.js b/rr-cache/index.js
@@ -1,4 +1,6 @@
 class RRCache {
+    #hits;
+    #misses;
     #capacity;
     #locked;
     #keys;
@@ -8,6 +10,8 @@ class RRCache {
         const { capacity } = options;
         if (!Number.isInteger(capacity) || capacity <= 0)
             throw new Error('invalid "capacity": positive integer expected');
+        this.#hits = 0;
+        this.#misses = 0;
         this.#capacity = capacity;
         this.#locked = false;
         this.#keys = new Array(capacity);
@@ -18,10 +22,11 @@ class RRCache {
         return {
             size: this.#store.size,
             capacity: this.#capacity,
-            locked: this.#locked
+            locked: this.#locked,
+            hitRatio: this.#hits / (this.#hits + this.#misses)
         };
     }
-    set locked(state) {
+    set lock(state) {
         this.#locked = state;
     }
     /**
@@ -31,8 +36,10 @@ class RRCache {
      */
     read(key) {
         if (this.#store.has(key)) {
+            this.#hits += 1;
             return this.#store.get(key).value;
         }
+        this.#misses += 1;
         return null;
     }
     add(key, value) {

diff --git a/rr-cache/index.ts b/rr-cache/index.ts
@@ -5,14 +5,16 @@ type TStats = {
     capacity: number;
     // represent if cache is locked currently
     locked: boolean;
+    // measures how effective a cache is at fulfilling requests
+    hitRatio: number;
     // @todo: may contain other props like cache misses, etc.
 }
 
 interface IRRCache {
     // get cache statistics
     get stats(): TStats;
     // set lock state, if locked cache isn't growing
-    set locked(state: boolean);
+    set lock(state: boolean);
     // read value from cache by its key
     read: (key: any) => any;
     // add value to cache by corresponding key
@@ -35,6 +37,8 @@ type TConfigOptions = {
 }
 
 class RRCache implements IRRCache {
+    #hits: number;
+    #misses: number;
     #capacity: number;
     #locked: boolean;
     #keys: Array<any>;
@@ -46,6 +50,8 @@ class RRCache implements IRRCache {
 
         if (!Number.isInteger(capacity) || capacity <= 0) throw new Error('invalid "capacity": positive integer expected');
 
+        this.#hits = 0;
+        this.#misses = 0;
         this.#capacity = capacity;
         this.#locked = false;
         this.#keys = new Array(capacity);
@@ -57,11 +63,12 @@ class RRCache implements IRRCache {
         return {
             size: this.#store.size,
             capacity: this.#capacity,
-            locked: this.#locked
+            locked: this.#locked,
+            hitRatio: this.#hits / (this.#hits + this.#misses)
         };
     }
 
-    set locked (state: boolean) {
+    set lock (state: boolean) {
         this.#locked = state;
     }
 
@@ -72,9 +79,11 @@ class RRCache implements IRRCache {
      */
     read (key: any) {
         if (this.#store.has(key)) {
+            this.#hits += 1;
             return this.#store.get(key).value;
         }
 
+        this.#misses += 1;
         return null;
     }
 

diff --git a/rr-cache/readme.md b/rr-cache/readme.md
@@ -7,7 +7,7 @@
 | Operation  | Time complexity | Space complexity | Description                               |
 |------------|-----------------|------------------|-------------------------------------------|
 | `stats`    | $O(1)$          | $O(1)$           | Get cache statistics.                     |
-| `locked`   | $O(1)$          | $O(1)$           | Set lock state.                           |
+| `lock`     | $O(1)$          | $O(1)$           | Set lock state.                           |
 | `read`     | $O(1)$          | $O(1)$           | Read value by its key.                    |
 | `add`      | $O(1)$          | $O(1)$           | Add value by corresponding key.           |
 | `has`      | $O(1)$          | $O(1)$           | Check if there is a value by given key.   |