linked list

linkedList.js

function Linkedlist(){
this.head = null;


}
Linkedlist.prototype.isEmpty = function(){
return this.head === null;
};
//////////////////////////////////////
Linkedlist.prototype.size = function(){
  let current = this.head;
  let count = 0;
  while(current !== 0){
    count ++;
    current = current.next;
  }
  return current;
};
//////////////////////////////////////////
Linkedlist.prototype.prepend = function(x){

let newNode = {
  data: x ,
  next: this.head 

}
this.head = newNode // to be the first one in the list 
}
//////////////////////////////////////////////
Linkedlist.prototype.append = function(x){
  let newNode = {
    data:x,
    next: null // the last one in the list 
  }
  if (this.isEmpty()){
    this.head = newNode;
    return;
  }
  let current = this.head
while (current.next !== null) {
// stop at the the one before the last , becuase the last is null which is the newNode

 current = current.next;

}
current.next = newNode;
}

///////////////////////////
Linkedlist.prototype.contains =function(x){
  let current= this.head;
  while(current !== null){
    if ( current.data === x){
    return true;
    }
    else{
      current= current.next;
    }
    }
    return false;
}

//////////////////////////////

Linkedlist.prototype.remove = function(x){
      
  if (!this.contains(x)){
      return; /// there is no x inside 
  }
  if ( this.head.data === x){
    this.head = this.head.next
    return ;
  }
  let previous = null;
  let current = this.head;
  while(current.data !== x){
  previous = current;
  current = current.next
  }
  prevois.next = current.next
};
//////////////////////
Linkedlist.prototype.print = function(){
  let output = "[";
  current= this.head;
  while(current !== null){
   output += current.data;
   if(current.next !== null ){
   output += ",";
   }
   current= current.next
  }
 output += "]";
 console.log(output)
}



let list = new Linkedlist();
list.prepend(10);
list.append(30);
list.append(24);
list.append(67);
list.append(77);
list.print();