---
title: Create a Stack Class
---
# Create a Stack Class

---
## Problem Explanation
- Stack is an abstract data structure.
- Stack follows LIFO/FILO principle.
- In this challenge, we need to add `.push()`, `.pop()`, `.peek()`, `.isEmpty()` and `.clear()` methods to the class.
- 
  - `push()` method pushes value to the stack.
  - `pop()` method pops the first value from the stack.
  - `peek()` method returns the first value from the stack.
  - `isEmpty()` method checks if ths stack is empty.
  - `.clear()` method removes all the elements from the stack.
-
| DS    | Access | Search | Insert | Delete |
| ----- | ------ | ------ | ------ | ------ |
| Stack |   n    |    n   |   1    |    1   |


---
## Solutions

<details><summary>Solution 1 (Click to Show/Hide)</summary>

```js
function Stack() {
  var collection = [];
  this.print = function() {
    console.log(collection);
  };
  this.push = function(val) {
    return collection.push(val);
  };
  this.pop = function() {
    return collection.pop();
  };
  this.peek = function() {
    return collection[collection.length - 1];
  };
  this.isEmpty = function() {
    return collection.length === 0;
  };
  this.clear = function() {
    collection.length = 0;
  };
}
```
</details>

<details><summary>Solution 2 (Click to Show/Hide)</summary>

```js
class Stack {
  constructor() {
    this.collection = [];
  }
  print() {
    console.log(this.collection);
  }
  push(val) {
    return this.collection.push(val);
  }
  pop() {
    return this.collection.pop();
  }
  peek() {
    return this.collection[this.collection.length - 1];
  }
  isEmpty() {
    return this.collection.length === 0;
  }
  clear() {
    return (this.collection.length = 0);
  }
}
```
 #### Relevant Links
 
- [Wikipedia](https://en.wikipedia.org/wiki/Stack_(abstract_data_type))
</details>