Linked List Implementation

linkedlist-es6.js

// LINKEDLIST NODE 
class Node {
  constructor(data){
    this.data = data;
    this.next = null;
  }
}

// LINKEDLIST IMPLEMENTATION
class LinkedList {
  
  constructor(){
    this.head = null;
    this.size = 0;
  }
  
  add(data) {
    let node = new Node(data);
    
    if(this.head === null) {
      this.head = node;
    }
    else {
      let curr = this.head;
      while(curr.next != null) {
        curr = curr.next;
      }
      curr.next = node;
    }
    this.size++;
  }
  
  //
  insertAt(data, location) {
    if(location > 0 && location > this.size) {
      return false;
    }
    else {
      let curr, prev;
      let node = new Node(data);
      
      if(location === 0) {
        node.next = this.head;
        this.head = node;
      }
      else {
        curr = this.head;
        let i = 0;
        while(i < location){
          i++;
          prev = curr;
          curr = curr.next;
        }
        prev.next = node;
        node.next = curr;
      }
    }
    this.size++;
  }
  
  removeFrom(location) {
    if(location > 0 && location > this.size) {
      return false;
    }
    else {
      let curr = this.head, prev;
      if(location === 0) {
        this.head = curr.next;
      }
      else {
        curr = this.head;
        let i = 0;
        while(i < location){
          i++;
          prev = curr;
          curr = curr.next;
        }
        prev.next = curr.next;
      }
      this.size--;
      return curr.data;
    }
    
  }
  
  removeElement(data) {
    let curr = this.head,
        prev = null;
    while(curr !== null) {
      if(curr.data === data) {
        if(prev === null) {
          this.head = curr.next;
        }
        else {
          prev.next = curr.next;
        }
        this.size--;
        return curr.data;
      }
      prev = curr;
      curr = curr.next;
    }
    
    return -1;
  }
  
  printList() {
    var curr = this.head;
    while(curr !== null) {
      console.log(curr.data);
      curr = curr.next;
    }
  }
  
  getSize() {
    return this.size;
  }
  
  isEmpty() {
    return this.size === 0;
  }
  
}

// LINKEDLIST USAGE
let llist = new LinkedList();
console.log('is Empty :: ' + llist.isEmpty());
console.log('Size :: '+ llist.getSize());
llist.add(1);
llist.add(3);
llist.add(4);
llist.add(5);
llist.add(6);

llist.insertAt(2, 1);

console.log('removed :: ' + llist.removeFrom(5));
console.log('removed :: ' + llist.removeElement(1));
console.log('is Empty :: ' + llist.isEmpty());
console.log('Size ::' + llist.getSize());
llist.printList();

output.txt

"is Empty :: true"
"Size :: 0"
"removed :: 6"
"removed :: 1"
"is Empty :: false"
"Size ::4"
2
3
4
5