stack.ts

class Stack {
  #stack = [];

  push(item) {
    this.#stack.unshift(item);
    return this;
  }

  peep() {
    return this.#stack;
  }

  size() {
    return this.#stack.length;
  }

  isEmpty() {
    return this.#stack.length === 0;
  }

  empty() {
    this.#stack = [];
  }

  pop() {
    this.#stack = this.#stack.slice(1);
  } 

  head() {
    return this.#stack[0];
  }
  
  tail() {
    return this.#stack[this.#stack.length - 1];
  }
}