Method peek

src/data-structures/stack/Stack.js:22–30

* @return {*}

()

   * @return {*}
   */
  peek() {
    if (this.isEmpty()) {
      // If the linked list is empty then there is nothing to peek from.
      return null;
    }

    // Just read the value from the start of linked list without deleting it.
    return this.linkedList.head.value;
  }

  /**
   * @param {*} value