linkedList.js

class LinkedListNode {
  constructor(value) {
    this.value = value;
    this.next = null;
  }
}

const head = Symbol("linked list's head");

class LinkedList {
  constructor() {
    this[head] = null;
  }

  size() {
    let count = 0;
    let current = this[head];
    while (current) {
      current = current.next;
      count++;
    }
    return count;
  }

  add(value) {
    let lastNode = this[head];
    let newNode = new LinkedListNode(value);
    if (lastNode === null) {
      return (this[head] = newNode);
    }

    while (lastNode.next) {
      lastNode = lastNode.next;
    }
    lastNode.next = newNode;
  }
  remove(index) {
    if (index < 0 || this[head] === null) {
      throw new RangeError(`Index ${index} does not exist in the list.`);
    }

    if (index === 0) {
      this[head] = this[head].next;
    }

    let i = 0;
    let current = this[head];
    let previous = null;
    while (current && i < index) {
      previous = current;
      current = current.next;
      i++;
    }
    if (current) {
      previous.next = current.next;
      return current.value;
    }
    throw new RangeError(`Index ${index} does not exist in the list.`);
  }
  get(index) {
    if (index < 0) return undefined;
    let i = 0;
    let current = this[head];
    while (current && i < index) {
      current = current.next;
      i++;
    }

    return current !== null ? current.value : undefined;
  }
  clear() {
    this[head] = null;
    return true;
  }
  *values() {
    let current = this[head];

    while (current !== null) {
      yield current.value;
      current = current.next;
    }
  }
  [Symbol.iterator]() {
    return this.values();
  }
}

let linkedList = new LinkedList();
linkedList.add(0);
linkedList.add(1);
linkedList.add(2);
console.log("remove", linkedList.remove(1));
console.log('size', linkedList.size());

console.log([...linkedList])