DataStructure_JavaScript/Stack_Linkedlist.js at master · getsalman/DataStructure_JavaScript · GitHub

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//-> Stack using Linked List:-
class Stack {
  constructor() {
    this.top = null;
    this.bottom = null;
    this.length = 0;
  }

  peek() {
    return this.top;
  }

  push(value) {
    const newNode = {
      value: value,
      next: null,
    };
    if (this.length === 0) {
      this.top = newNode;
      this.bottom = newNode;
    } else {
      const holdingPointer = this.top;
      this.top = newNode;
      this.top.next = holdingPointer;
    }
    this.length++;
    return this;
  }

  pop() {
    if (!this.top) {
      return null;
    }
    if (this.top === this.bottom) {
      this.bottom = null;
    }
    this.top = this.top.next;
    this.length--;
    return this;
  }
}

const myStack = new Stack();
myStack.push("google");
myStack.push("udemy");
myStack.push("yahoo india");
myStack.peek();
myStack.pop();
myStack.pop();
myStack.pop();