Data Structures In JavaScript

Stack

Definition

• linear data structure
• Last in first out (LIFO) or first in last out (first in last out)
• operations on only one end
• push add element to stack
• pop remove element from stack

Extended Definition

• peek return the last value added to the stack without changing the stack
• size return the size of the stack

Stack Implementation in JavaScript

Array as a Stack

There are many ways the definition of a stack can be implemented in JavaScript we will start with a sufficient implementation the build in array method.

let stack = []

stack.push("a")
stack.push("b")
stack.push("c")
console.log(stack) // ['a', 'b', 'c']

stack.pop() // 'c'
console.log(stack) // ['a', 'b']

By constraining how we used the array object we can leverage it as a stack. This is useful when using a stack and it's properties is ideal for solving a challenge.

for example reverse a string;

function reverse(str) {
  let stack = []
  for (let i = 0; i < str.length; i++) {
    stack.push(str[i])
  }
  let reverseStr = ""
  for (let j = 0; j < str.length; j++) {
    reverseStr += stack.pop()
  }
  return reverseStr
}

reverse("hello world") // dlrow olleh

Class Implementation Stack One

class Stack {
  constructor() {}
}