JavaScript Exercises: Convert a Singly Linked list into an array

JavaScript Singly Linked List: Exercise-15 with Solution

Convert a SLL into an array

Write a JavaScript program to convert a Singly Linked list into an array.

Sample Solution:

JavaScript Code:

// Define a class representing a node in a singly linked list
class Node {
    constructor(data) {
        // Initialize the node with provided data
        this.data = data;
        // Initialize the next pointer to null
        this.next = null;
    }
}

// Define a class representing a singly linked list
class SinglyLinkedList {
    constructor(Head = null) {
        // Initialize the head of the list
        this.Head = Head;
    }

    // Method to add a new node to the end of the list
    add(newNode) {
        // Start traversal from the head node
        let node = this.Head;
        // If the list is empty, set the new node as the head and return
        if (node == null) {
            this.Head = newNode;
            return;
        }
        // Traverse the list until the last node
        while (node.next) {
            node = node.next;
        }
        // Set the next pointer of the last node to the new node
        node.next = newNode;
    }

    // Method to convert the linked list to an array
    to_array() {
        // Initialize an empty array to store the elements of the list
        let current = this.Head;
        let arr = [];
        // Traverse the list and push each element to the array
        while (current) {
            arr.push(current.data);
            current = current.next;
        }
        return arr;
    }

    // Method to display the elements of the list
    displayList() {
        // Start traversal from the head node
        let node = this.Head;
        // Initialize an empty string to store the elements of the list
        var str = "";
        // Traverse the list and concatenate each element to the string
        while (node) {
            str += node.data + "->";
            node = node.next;
        }
        // Append "NULL" to indicate the end of the list
        str += "NULL";
        // Print the string containing the list elements
        console.log(str);
    }
}

// Create an instance of the SinglyLinkedList class
let numList = new SinglyLinkedList();
// Add nodes with data values to the list
numList.add(new Node(12));
numList.add(new Node(13));
numList.add(new Node(14));
numList.add(new Node(15));
numList.add(new Node(14));
// Display the elements of the list
console.log("Singly Linked list:");
numList.displayList();
// Convert the linked list to an array
console.log("Converts the said Singly Linked Lists into an array");
result = numList.to_array();
console.log(result);

// Create a new instance of the SinglyLinkedList class
let numList1 = new SinglyLinkedList();
// Display the elements of the empty list
console.log("New Singly Linked list:");
numList1.displayList();
// Convert the empty linked list to an array
console.log("Converts the said Singly Linked Lists into an array");
result = numList1.to_array();
console.log(result);

Output:

Singly Linked list:
12->13->14->15->14->NULL
Converts the said Singly Linked Lists into an array
[12,13,14,15,14]
New Singly Linked list:
NULL
Converts the said Singly Linked Lists into an array
[]

Flowchart:

Live Demo:

See the Pen javascript-singly-linked-list-exercise-15 by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript function that traverses a singly linked list and pushes each node’s value into a new array.
• Write a JavaScript function that recursively converts a singly linked list into an array of node values.
• Write a JavaScript function that converts a singly linked list to an array and then prints the array as a comma-separated string.
• Write a JavaScript function that validates the linked list and returns an empty array if the list is null.

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