separate queue example into own file

Author: zacjones93

queues/index.js

@@ -26,15 +26,4 @@ function createQueue() {
   }
 }
 
-
-const q = createQueue()
-
-q.enqueue('Make an egghead lesson')
-q.enqueue('Help others learn')
-q.enqueue('Be happy')
-
-q.dequeue()
-q.dequeue()
-console.log(q.peek())
-
 exports.createQueue = createQueue

queues/package.json

@@ -2,7 +2,7 @@
   "name": "intro-to-data-structures-and-algorithms",
   "version": "1.0.0",
   "description": "An egghead course to introduce data structures and algorithms in JavaScript",
-  "main": "index.js",
+  "main": "queues.js",
   "scripts": {
     "test": "jest",
     "test:watch": "jest --watch"

queues/queues.js

@@ -0,0 +1,40 @@
+function createQueue() {
+  const queue = []
+
+  return {
+    enqueue(x) {
+      queue.unshift(x)
+    },
+    dequeue() {
+      if (queue.length === 0) {
+        return undefined
+      }
+      return queue.pop()
+    },
+    peek() {
+      if (queue.length === 0) {
+        return undefined
+      }
+      return queue[queue.length - 1]
+    },
+    get length() {
+      return queue.length
+    },
+    isEmpty() {
+      return queue.length === 0
+    }
+  }
+}
+
+
+const q = createQueue()
+
+q.enqueue('Make an egghead lesson')
+q.enqueue('Help others learn')
+q.enqueue('Be happy')
+
+q.dequeue()
+q.dequeue()
+console.log(q.peek())
+
+exports.createQueue = createQueue