feat: get method

src/DataStructures/LinkedList.js

@@ -1,5 +1,3 @@
-import { isValidNumber } from "../Maths";
-
 export class Node {
 	constructor(value) {
 		this.value = value;
@@ -9,7 +7,7 @@ export class Node {
 
 export class LinkedList {
 	constructor(value) {
-		if (isValidNumber(value)) {
+		if (value !== undefined) {
 			const newNode = new Node(value);
 			this.head = newNode;
 			this.tail = newNode;
@@ -37,6 +35,20 @@ export class LinkedList {
 		return this;
 	}
 
+	get(index) {
+		if (index < 0 || index >= this.size) return undefined;
+
+		let count = 0;
+		let temp = this.head;
+		while (temp !== null) {
+			if (count === index) return temp.value;
+			temp = temp.next;
+			count++;
+		}
+
+		return temp; // Should never reach here
+	}
+
 	// ADD a new value to the END of the list
 	push(value) {
 		const newNode = new Node(value);

tests/DataStructures/LinkedList.test.js

@@ -40,6 +40,50 @@ describe("LinkedList.js", () => {
 			});
 		});
 
+		describe("get()", () => {
+			it("should return value by the passed index", () => {
+				const ll = new LinkedList(100);
+				ll.push(20);
+				ll.push(30);
+
+				expect(ll.get(0)).toBe(100);
+				expect(ll.get(1)).toBe(20);
+				expect(ll.get(2)).toBe(30);
+			});
+
+			it("should return undefined in a empty list", () => {
+				const ll = new LinkedList();
+				expect(ll.get(0)).toBe(undefined);
+				expect(ll.get(1)).toBe(undefined);
+				expect(ll.get(10)).toBe(undefined);
+			});
+
+			it("should return undefined in a empty list", () => {
+				const ll = new LinkedList();
+				expect(ll.get(0)).toBe(undefined);
+				expect(ll.get(1)).toBe(undefined);
+				expect(ll.get(10)).toBe(undefined);
+			});
+
+			it("should return undefined if try to get a index less than 0 or greater than the list size", () => {
+				const ll = new LinkedList();
+				expect(ll.get(-1)).toBe(undefined);
+				expect(ll.get(-10)).toBe(undefined);
+			});
+
+			it("should return undefined if try to get a index greater than the list size", () => {
+				const ll = new LinkedList(10);
+				expect(ll.get(0)).toBe(10);
+				expect(ll.get(1)).toBe(undefined);
+				expect(ll.get(2)).toBe(undefined);
+
+				ll.push(25);
+				expect(ll.get(1)).toBe(25);
+				expect(ll.get(2)).toBe(undefined);
+				expect(ll.get(10)).toBe(undefined);
+			});
+		});
+
 		describe("push()", () => {
 			it("adds items to the end of the linked list", () => {
 				const ll = new LinkedList(100);