Stack.js

//lets make a function the returns Hello would 
const add = (a, b) => {
    if(a && b){
        return a + b
    }
   return 'No Numbers'
}
const subtract = (a, b) => {
    if(a, b){
        return a - b
    }
   return 'No Numbers '
}

const addAndSubtract = (a, b) => {
   let num1 = add(a, b)//=> 1500
   let num2 = subtract(a, b)//=> -500
   return num1 + num2 /// 1500 + (-500) = 1000
}

addAndSubtract(500, 1000)
//=> 1000

//so the call stack would look like this.
|addAndSubtract|
//addAndSubtract is placed on the stack, then if we step inside this function the stack will look like this:
|add           | 
|addAndsubtract|
//after execution, it will go to the next line of code and execute subtract.
|subtract      | 
|addAndsubtract|
// once there is no code left inside the function we return a number and the function is poped of the stack.
|addAndSubtract|
// not paused
  
//=> The first function that gets call is addAndSubtract function, we then set inside the function scope and we get two new functions added to the stack.