JavaScript Exercises: Get index of an given element in a Singly Linked list

JavaScript Singly Linked List: Exercise-17 with Solution

Write a JavaScript program to get the index of an element in a Singly Linked list.

Sample Solution:

JavaScript Code:

class Node {
    constructor(data) {
        this.data = data;
        this.next = null;               
    }
}
class SinglyLinkedList {
    constructor(Head = null) {
        this.Head = Head;
    }  
add(newNode){
    let node = this.Head;
    if(node==null){
        this.Head = newNode;
        return;
    }
    while (node.next) {
        node = node.next;
    }
    node.next = newNode;
}
  
 index_of(el) {
  let index = 0;
  let node = this.Head; 
  while (node) {
    if (node.data === el) {
      return index;
    }
    node = node.next;
    index++;
  }
  return -1;
 } 
 displayList(){
    let node = this.Head;
    var str = ""
    while (node) {
        str += node.data + "->";
        node = node.next;
    }
    str += "NULL"
    console.log(str);  
  }
}
let numList = new SinglyLinkedList();
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));
numList.add(new Node(16));
console.log("Singly Linked list:")
numList.displayList();
result = numList.index_of(12);
console.log("Index of 12 in the said link list: "+result);
result = numList.index_of(13);
console.log("Index of 13 in the said link list: "+result);
result = numList.index_of(14);
console.log("Index of 14 in the said link list: "+result);
result = numList.index_of(16);
console.log("Index of 16 in the said link list: "+result);

Sample Output:

Singly Linked list:
12->13->14->15->14->16->NULL
Index of 12 in the said link list: 0
Index of 13 in the said link list: 1
Index of 14 in the said link list: 2
Index of 16 in the said link list: 5

Flowchart:

Live Demo:

See the Pen javascript-singly-linked-list-exercise-17 by w3resource (@w3resource) on CodePen.

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