Rename CacheElement; LRUCache Logic Fixes

Author: opti-jnguyen

packages/optimizely-sdk/lib/core/odp/lru_cache/LRUCacheElement.tests.ts renamed to packages/optimizely-sdk/lib/core/odp/lru_cache/CacheElement.tests.ts

@@ -15,20 +15,20 @@
  */
 
 import { assert } from 'chai'
-import { LRUCacheElement } from './LRUCacheElement';
+import { CacheElement } from './CacheElement';
 
 const sleep = async (ms: number) => {
     return await new Promise(r => setTimeout(r, ms))
 }
 
-describe('/odp/lru_cache/LRUCacheElement', () => {
-    let element: LRUCacheElement<string>
+describe('/odp/lru_cache/CacheElement', () => {
+    let element: CacheElement<string>
 
     beforeEach(() => {
-        element = new LRUCacheElement('foo')
+        element = new CacheElement('foo')
     })
 
-    it('should initialize a valid LRUCacheElement', () => {
+    it('should initialize a valid CacheElement', () => {
         assert.exists(element)
         assert.equal(element.value, 'foo')
         assert.isNotNull(element.time)

packages/optimizely-sdk/lib/core/odp/lru_cache/LRUCacheElement.ts renamed to packages/optimizely-sdk/lib/core/odp/lru_cache/CacheElement.ts

@@ -15,9 +15,9 @@
  */
 
 /**
- * LRUCacheElement represents an individual generic item within the LRUCache
+ * CacheElement represents an individual generic item within the LRUCache
  */
-export class LRUCacheElement<V> {
+export class CacheElement<V> {
     private _value: V | null
     private _time: number
 
@@ -35,4 +35,4 @@ export class LRUCacheElement<V> {
     }
 }
 
-export default LRUCacheElement
+export default CacheElement

packages/optimizely-sdk/lib/core/odp/lru_cache/LRUCache.tests.ts

@@ -182,9 +182,9 @@ describe('/lib/core/odp/lru_cache (Default)', () => {
 
             await sleep(150)
 
-            assert.isNull(cache.peek('a'))
-            assert.isNull(cache.peek('b'))
-            assert.isNull(cache.peek('c'))
+            assert.isNull(cache.lookup('a'))
+            assert.isNull(cache.lookup('b'))
+            assert.isNull(cache.lookup('c'))
 
             cache.save({ key: 'd', value: 400 })            // { d: 400 }
             cache.save({ key: 'a', value: 101 })            // { d: 400, a: 101 }

packages/optimizely-sdk/lib/core/odp/lru_cache/LRUCache.ts

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-import LRUCacheElement from "./LRUCacheElement"
+import CacheElement from "./CacheElement"
 
 /**
  * Least-Recently Used Cache (LRU Cache) Implementation with Generic Key-Value Pairs
@@ -23,17 +23,17 @@ import LRUCacheElement from "./LRUCacheElement"
  * - Removes stale elements (entries older than their timeout) from the cache.
  */
 export class LRUCache<K, V> {
-    private _map: Map<K, LRUCacheElement<V>> = new Map()
-    private _maxSize = 100 // Defines maximum size of _map
-    private _timeout = 1000 * 600 // Milliseconds each entry has before it becomes stale
+    private _map: Map<K, CacheElement<V>> = new Map()
+    private _maxSize // Defines maximum size of _map
+    private _timeout // Milliseconds each entry has before it becomes stale
 
-    get map(): Map<K, LRUCacheElement<V>> { return this._map }
+    get map(): Map<K, CacheElement<V>> { return this._map }
     get maxSize(): number { return this._maxSize }
     get timeout(): number { return this._timeout }
 
-    constructor({ maxSize, timeout }: { maxSize?: number, timeout?: number }) {
-        if (maxSize != undefined) this._maxSize = maxSize
-        if (timeout != undefined) this._timeout = timeout
+    constructor({ maxSize, timeout }: { maxSize: number, timeout: number }) {
+        this._maxSize = maxSize
+        this._timeout = timeout
     }
 
     /**
@@ -43,19 +43,18 @@ export class LRUCache<K, V> {
     public lookup(key: K): V | null {
         if (this._maxSize <= 0) { return null }
 
-        const element: LRUCacheElement<V> | undefined = this._map.get(key)
+        const element: CacheElement<V> | undefined = this._map.get(key)
 
         if (!element) return null
 
-        this._map.delete(key)
-        this._map.set(key, element)
-
-
         if (element.is_stale(this._timeout)) {
             this._map.delete(key)
             return null
         }
 
+        this._map.delete(key)
+        this._map.set(key, element)
+
         return element.value
     }
 
@@ -66,9 +65,9 @@ export class LRUCache<K, V> {
     public save({ key, value }: { key: K, value: V }): void {
         if (this._maxSize <= 0) return
 
-        const element: LRUCacheElement<V> | undefined = this._map.get(key)
+        const element: CacheElement<V> | undefined = this._map.get(key)
         if (element) this._map.delete(key)
-        this._map.set(key, new LRUCacheElement(value))
+        this._map.set(key, new CacheElement(value))
 
         if (this._map.size > this._maxSize) {
             const firstMapEntryKey = this._map.keys().next().value
@@ -87,18 +86,12 @@ export class LRUCache<K, V> {
 
     /**
      * Reads value from specified key without moving elements in the LRU Cache.
-     * Removes the element if it is stale.
      * @param {K} key
      */
     public peek(key: K): V | null {
         if (this._maxSize <= 0) return null
 
-        const element: LRUCacheElement<V> | undefined = this._map.get(key)
-
-        if (element?.is_stale(this._timeout)) {
-            this._map.delete(key)
-            return null
-        }
+        const element: CacheElement<V> | undefined = this._map.get(key)
 
         return element?.value ?? null
     }