Add annotations to Queue.

src/data-structures/queue/Queue.js

@@ -5,10 +5,16 @@ export default class Queue {
     this.linkedList = new LinkedList();
   }
 
+  /**
+   * @return {boolean}
+   */
   isEmpty() {
     return !this.linkedList.tail;
   }
 
+  /**
+   * @return {*}
+   */
   peek() {
     if (!this.linkedList.head) {
       return null;
@@ -17,15 +23,25 @@ export default class Queue {
     return this.linkedList.head.value;
   }
 
+  /**
+   * @param {*} value
+   */
   enqueue(value) {
     this.linkedList.append(value);
   }
 
+  /**
+   * @return {*}
+   */
   dequeue() {
     const removedHead = this.linkedList.deleteHead();
     return removedHead ? removedHead.value : null;
   }
 
+  /**
+   * @param [callback]
+   * @return {string}
+   */
   toString(callback) {
     return this.linkedList.toString(callback);
   }