LinkedList.ts
For the full content of this gist, refer to https://gist.github.com/CodingAbdullah/2dbf6f1b59833f1712a24e1db72b94e2
McMaster. Software Engineer with a keen interest in blockchain and web3.
// Recursive data which segments each Node with value
// Next node is given a reference to the previous node connecting it
class Node<T> {
next: Node<T> | null = null;
value: T
// Set data of current node and set next reference to null
constructor(data: T){
this.value = data;
this.next = null;
}
}
export default class LinkedList<T> {
headNode: Node<T> | null
constructor() {
this.headNode = null
}
insert(data: T): void {
// If list is empty, initialize it with value
if (this.headNode === null) {
this.headNode = new Node(data);
}
else {
// If head node exists, start at there and work your way down
let currentNode = this.headNode;
// Keep iterating until you reach the tail (or when next reference is null)
while (currentNode.next !== null) {
currentNode = currentNode.next;
}
currentNode.next = new Node(data); // Append node to end of list
}
}
delete(data: T): T | null {
let currentNode = this.headNode;
if (currentNode === null){
return null;
}
else if (currentNode.value === data) {
this.headNode = currentNode.next; // Delete the first node from list
return data;
}
else {
let precedingNode = currentNode;
currentNode = currentNode.next;
// Traverse through the linked list to find value
while (currentNode) {
if (currentNode?.value === data) {
let nodeValue = currentNode.value;
precedingNode.next = currentNode.next;
return nodeValue;
}
precedingNode = currentNode;
currentNode = currentNode.next; // Node is deleted
}
return null; // If after traversing through the entire list and no value is found, return null
}
}
// Recursively iterate through the list to find values and append for display
print(): void {
let listDisplay = '';
let currentNode = this.headNode;
// Appending list values while iterating through Linked List
while (currentNode) {
listDisplay += '{ ';
listDisplay += currentNode.value;
listDisplay += ' }';
currentNode = currentNode.next;
}
// Finally print Linked List to console
console.log(listDisplay);
}
}
let ll = new LinkedList();
ll.insert(5);
ll.print();
ll.insert(21);
ll.print();
ll.insert(34);
ll.print();
ll.delete(6);
ll.print();
ll.delete(21);
ll.print();