Merge pull request #62 from oslabs-beta/refactor_and_add_redis_types

refactor: small code changes and added redis types

deno.json

@@ -6,6 +6,7 @@
     "oak": "https://deno.land/x/oak@v17.1.4/mod.ts",
     "oak/application": "https://deno.land/x/oak@v17.1.4/application.ts",
     "redis": "https://deno.land/x/redis@v0.37.1/mod.ts",
+    "redis/command": "https://deno.land/x/redis@v0.37.1/command.ts",
     "cors": "https://deno.land/x/cors@v1.2.2/mod.ts"
   }
 }

src/doublyLinkedLists.ts

@@ -13,7 +13,13 @@ export class Node {
   timeStamp: Date;
   parent?: FreqNode;
 
-  constructor(key: string, value: cacheValue, byteSize: number, timeStamp: Date, parent?: FreqNode){
+  constructor(
+      key: string,
+      value: cacheValue,
+      byteSize: number,
+      timeStamp: Date,
+      parent?: FreqNode
+  ) {
     this.next = null;
     this.prev = null;
     this.value = value;
@@ -34,7 +40,13 @@ export class ValueDoublyLinkedList {
     this.tail = null;
   }
 
-  public addHead(key: string, value: cacheValue, byteSize: number, timeStamp: Date, parent?: FreqNode){
+  public addHead(
+      key: string,
+      value: cacheValue,
+      byteSize: number,
+      timeStamp: Date,
+      parent?: FreqNode
+  ) {
     const node = new Node(key, value, byteSize, timeStamp, parent);
     if (!this.head) {
       this.head = node;
@@ -47,25 +59,47 @@ export class ValueDoublyLinkedList {
     return this.head;
   }
 
-  public delete(node: Node | null){
-    if (!node) return;
-    node.prev ?
-      node.prev.next = node.next
-      : this.head = node.next;
-    node.next ?
-      node.next.prev = node.prev
-      : this.tail = node.prev;
+  public delete(node: Node | null) {
+    if (!node) {
+      return;
+    }
+
+    if (node.prev) {
+      node.prev.next = node.next;
+    } else {
+      this.head = node.next;
+    }
+
+    if (node.next) {
+      node.next.prev = node.prev;
+    } else {
+      this.tail = node.prev;
+    }
+
     return node;
   }
 
-  public deleteTail(){
+  public deleteTail(): Node | null {
+    if (!this.tail) {
+        return null;
+    }
+
     const deleted = this.tail;
     if (this.head === this.tail) {
-      this.head = this.tail = null;
-    } else if (this.tail) {
-      this.tail = this.tail.prev
-      if (this.tail) this.tail.next = null;
+        // handle single-node case
+        this.head = this.tail = null;
+    } else {
+        // handle multiple-node case
+        this.tail = this.tail.prev;
+        if (this.tail) {
+            this.tail.next = null;
+        }
     }
+
+    // cleanup for deleted node's references
+    deleted.prev = null;
+    deleted.next = null;
+
     return deleted;
   }
 }
@@ -79,7 +113,7 @@ export class FreqNode {
   next: FreqNode | null;
   prev: FreqNode | null;
 
-  constructor(freqValue: number){
+  constructor(freqValue: number) {
     this.freqValue = freqValue;
     this.valList = new ValueDoublyLinkedList();
     this.next = null;
@@ -92,13 +126,13 @@ export class FreqDoublyLinkedList {
   head: FreqNode | null;
   tail: FreqNode | null;
 
-  constructor(){
+  constructor() {
     //head being lowest freq item, tail being highest.
     this.head = null;
     this.tail = null;
   }
 
-  public addNewFreq(key: string, value: cacheValue, byteSize: number, timeStamp: Date){
+  public addNewFreq(key: string, value: cacheValue, byteSize: number, timeStamp: Date) {
     if (!this.head) {
       this.head = new FreqNode(1);
       this.tail = this.head;
@@ -112,8 +146,11 @@ export class FreqDoublyLinkedList {
     return this.head.valList.addHead(key, value, byteSize, timeStamp, this.head);
   }
 
-  public increaseFreq(node: Node){
-    if (!node.parent) return;
+  public increaseFreq(node: Node) {
+    if (!node.parent) {
+        return;
+    }
+
     const { key, value, byteSize, timeStamp, parent } = node;
 
     //is highest freq
@@ -142,22 +179,37 @@ export class FreqDoublyLinkedList {
     this.deleteValNode(this.head.valList.tail)
     : undefined;
 
-  public deleteValNode(node: Node | null){
-    if (!node || !node.parent) return;
+  public deleteValNode(node: Node | null) {
+    if (!node || !node.parent) {
+        return;
+    }
+
     const { valList } = node.parent;
     valList.delete(node);
-    if (!valList.head) this.delete(node.parent);
+    if (!valList.head) {
+        this.delete(node.parent);
+    }
+
     return node;
   }
 
-  public delete(freqNode: FreqNode | null){
-    if (!freqNode) return;
-    freqNode.prev ?
-      freqNode.prev.next = freqNode.next
-      : this.head = freqNode.next;
-    freqNode.next ?
-      freqNode.next.prev = freqNode.prev
-      : this.tail = freqNode.prev;
+  public delete(freqNode: FreqNode | null) {
+    if (!freqNode) {
+      return;
+    }
+
+    if (freqNode.prev) {
+      freqNode.prev.next = freqNode.next;
+    } else {
+        this.head = freqNode.next;
+    }
+
+    if (freqNode.next) {
+      freqNode.next.prev = freqNode.prev;
+    } else {
+        this.tail = freqNode.prev;
+    }
+
     return freqNode;
   }
 }

src/lfu.ts

@@ -16,7 +16,7 @@ class LFU {
   expire: number;
   metrics: PerfMetrics;
 
-  constructor(expire: number, metrics: PerfMetrics, capacity: number){
+  constructor(expire: number, metrics: PerfMetrics, capacity: number) {
     this.freqList = new FreqDoublyLinkedList();
     this.cache = {};
     this.length = 0;
@@ -31,7 +31,7 @@ class LFU {
    * @param value
    * @returns
    */
-  public put(key: string, value: cacheValue, byteSize: number){
+  public put(key: string, value: cacheValue, byteSize: number) {
     if (this.cache[key]){
       this.metrics.decreaseBytes(this.cache[key].byteSize);
       this.metrics.increaseBytes(byteSize);
@@ -45,17 +45,19 @@ class LFU {
 
     if (this.length < this.capacity) {
       this.length++;
-    } else {
-      const deletedNode: Node | undefined = this.freqList.deleteLeastFreq();
-      if (!deletedNode) throw new Error('Node is null. Ensure cache capcity is greater than 0.');
-      delete this.cache[deletedNode.key];
-      this.metrics.decreaseBytes(deletedNode.byteSize);
+      return;
+    }
+
+    const deletedNode: Node | undefined = this.freqList.deleteLeastFreq();
+    if (!deletedNode) {
+        throw new Error('Node is null. Ensure cache capcity is greater than 0.');
     }
 
-    return;
+    delete this.cache[deletedNode.key];
+    this.metrics.decreaseBytes(deletedNode.byteSize);
   }
 
-  public get(key: string){
+  public get(key: string) {
     if (!this.cache[key]) return;
     //if entry is stale, deletes and exits
     const currentTime = new Date();
@@ -74,7 +76,7 @@ class LFU {
     }
   }
 
-  public delete(key: string){
+  public delete(key: string) {
     const node = this.cache[key];
     if (!node) return;
 
@@ -86,7 +88,7 @@ class LFU {
     return node;
   }
 
-  public clear(){
+  public clear() {
     this.freqList = new FreqDoublyLinkedList();
     this.cache = {};
     this.length = 0;

src/lru.ts

@@ -21,7 +21,6 @@ class LRU {
     this.capacity = capacity;
     this.expire = expire;
     this.metrics = metrics;
-
     this.get = this.get.bind(this);
     this.put = this.put.bind(this);
     this.delete = this.delete.bind(this);
@@ -34,7 +33,7 @@ class LRU {
    * @param value
    * @returns
    */
-  public put (key: string, value: cacheValue, byteSize: number)  {
+  public put(key: string, value: cacheValue, byteSize: number) {
     //if key alreadys exits in cache, replace key value with new value, and move to list head.
     if (this.cache[key]){
       this.metrics.decreaseBytes(this.cache[key].byteSize);
@@ -51,22 +50,24 @@ class LRU {
     //evalutes if least recently used item should be evicted.
     if (this.length < this.capacity) {
       this.length++;
-    } else {
-      const deletedNode: Node | null = this.list.deleteTail();
-      if (deletedNode === null) throw new Error('Node is null. Ensure cache capcity is greater than 0.');
-      delete this.cache[deletedNode.key];
-      this.metrics.decreaseBytes(deletedNode.byteSize);
+      return;
     }
 
-    return;
+    const deletedNode: Node | null = this.list.deleteTail();
+    if (deletedNode === null) {
+      throw new Error('Node is null. Ensure cache capcity is greater than 0.');
+    }
+
+    delete this.cache[deletedNode.key];
+    this.metrics.decreaseBytes(deletedNode.byteSize);
   }
 
   /**
    * Gets item from cache and moves to head -- most recently used.
    * @param key
    * @returns
    */
-  public get (key: string) {
+  public get(key: string) {
     //If no matching cache value (cache miss), return next();
     if (!this.cache[key]) return undefined;
 
@@ -80,7 +81,9 @@ class LRU {
     }
 
     // if current key is already node at head of list, return immediately.
-    if (this.cache[key] === this.list.head) return this.list.head.value;
+    if (this.cache[key] === this.list.head) {
+        return this.list.head.value;
+    }
 
     //create new node, then delete node at current key, to replace at list head.
     const node = this.cache[key];
@@ -97,7 +100,7 @@ class LRU {
    * @param key
    * @returns
    */
-  public delete (key: string) {
+  public delete(key: string) {
     const node = this.cache[key];
     if (!node) return;
 
@@ -111,7 +114,7 @@ class LRU {
   /**
    * Clears entire cache contents.
    */
-  public clear () {
+  public clear() {
     this.list = new ValueDoublyLinkedList();
     this.cache = {};
     this.length = 0;

src/performanceMetrics.ts

@@ -42,6 +42,7 @@ class PerfMetrics {
       this.currentMissLatency = latency;
       return;
     }
+
     throw new TypeError('Hit or miss not specified');
   };
 }

zoic.ts

@@ -15,7 +15,7 @@ import LFU from './src/lfu.ts'
   *
   * ```ts
   *
-  * import { Zoic } from "https://deno.land/x/ozoic/zoic.ts"
+  * import { Zoic } from "https://deno.land/x/zoic"
   *
   * const cache = new Zoic({
   *   cache: 'LRU',