feature: added return of removed element when queue is full

hbarcelos · hbarcelos · commit 96d968044141 · 2020-02-05T13:35:54.000-03:00
diff --git a/round-linked-queue.js b/round-linked-queue.js
@@ -30,6 +30,8 @@ class RoundLinkedQueue {
       next: null,
     };
 
+    let removedElement;
+
     if (this.length < this.maxLength) {
       if (!this._first) {
         this._first = node;
@@ -38,11 +40,14 @@ class RoundLinkedQueue {
 
       this._length += 1;
     } else {
+      removedElement = this._first.data;
       this._first = this._first.next;
     }
 
     this._last.next = node;
     this._last = node;
+
+    return removedElement;
   }
 }
 
diff --git a/round-linked-queue.test.js b/round-linked-queue.test.js
@@ -70,5 +70,24 @@ describe("Round-Queue", () => {
       // Length should still be the same
       expect(queue.length).to.equal(3, "length not properly set");
     });
+
+    it("Should return the removed element from a full queue", () => {
+      const queue = new RoundQueue(3);
+      queue.add(1);
+      queue.add(2);
+      queue.add(3);
+
+      const result = queue.add(4);
+
+      expect(result).to.equal(1, "removed wrong element");
+    });
+
+    it("Should return undefined when the queue is not full", () => {
+      const queue = new RoundQueue(3);
+
+      const result = queue.add(1);
+
+      expect(result).to.equal(undefined, "should not return an element");
+    });
   });
 });

Original file line number	Diff line number	Diff line change
`@@ -30,6 +30,8 @@ class RoundLinkedQueue {`
`30`	`30`	`next: null,`
`31`	`31`	`};`
`32`	`32`
	`33`	`+ let removedElement;`
	`34`	`+`
`33`	`35`	`if (this.length < this.maxLength) {`
`34`	`36`	`if (!this._first) {`
`35`	`37`	`this._first = node;`
`@@ -38,11 +40,14 @@ class RoundLinkedQueue {`
`38`	`40`
`39`	`41`	`this._length += 1;`
`40`	`42`	`} else {`
	`43`	`+ removedElement = this._first.data;`
`41`	`44`	`this._first = this._first.next;`
`42`	`45`	`}`
`43`	`46`
`44`	`47`	`this._last.next = node;`
`45`	`48`	`this._last = node;`
	`49`	`+`
	`50`	`+ return removedElement;`
`46`	`51`	`}`
`47`	`52`	`}`
`48`	`53`